Imperial Japanese rule (1910–1945)

Imperial Japan severely diminished the influence of China over Korea in the First Sino-Japanese War (1894–95), ushering in the short-lived Korean Empire.^[57] A decade later, after defeating Imperial Russia in the Russo-Japanese War (1904–05), Japan made the Korean Empire its protectorate with the Eulsa Treaty in 1905, then annexed it with the Japan–Korea Annexation Treaty in 1910. After that, the Korean Empire fell, and Korea was directly ruled by Japan from 1910 to 1945.^[58]

Many Korean nationalists fled the country. The Provisional Government of the Republic of Korea was founded in 1919 in Nationalist China. It failed to achieve international recognition, failed to unite the various nationalist groups, and had a fractious relationship with its U.S.-based founding president, Syngman Rhee.^[59] From 1919 to 1925 and beyond, Korean communists led internal and external warfare against the Japanese.^[60][61]

In China, the nationalist National Revolutionary Army and the communist People's Liberation Army (PLA) helped organize Korean refugees against the Japanese military, which had also occupied parts of China. The Nationalist-backed Koreans, led by Yi Pom-Sok, fought in the Burma campaign (December 1941 – August 1945). The communists, led by, among others, Kim Il Sung, fought the Japanese in Korea and Manchuria.^[62]

At the Cairo Conference in November 1943, China, the United Kingdom and the United States all decided that "in due course Korea shall become free and independent".^[63]

Korea divided (1945–1949)

At the Tehran Conference in November 1943 and the Yalta Conference in February 1945, the Soviet Union promised to join its allies in the Pacific War within three months of the victory in Europe. Germany officially surrendered on 8 May 1945, and the USSR declared war on Japan and invaded Manchuria on 8 August 1945, three months later. This was three days after the atomic bombing of Hiroshima.^[61][64] By 10 August, the Red Army had begun to occupy the north of Korea.^[65]

On the night of 10 August in Washington, U.S. Colonels Dean Rusk and Charles H. Bonesteel III were assigned to divide Korea into Soviet and U.S. occupation zones and proposed the 38th parallel as the dividing line. This was incorporated into the U.S. General Order No. 1, which responded to the Japanese surrender on 15 August. Explaining the choice of the 38th parallel, Rusk observed, "even though it was further north than could be realistically reached by U. S. [sic] forces in the event of Soviet disagreement ... we felt it important to include the capital of Korea in the area of responsibility of American troops". He noted that he was "faced with the scarcity of U.S. forces immediately available and time and space factors which would make it difficult to reach very far north before Soviet troops could enter the area".^[66][67] As Rusk's comments indicate, the U.S. doubted whether the Soviet government would agree to this.^{[68][69][70][71]} Soviet leader Joseph Stalin, however, maintained his wartime policy of co-operation, and on 16 August the Red Army halted at the 38th parallel for three weeks to await the arrival of U.S. forces in the south.^[65]

On 7 September 1945, General Douglas MacArthur issued Proclamation No. 1 to the people of Korea, announcing U.S. military control over Korea south of the 38th parallel and establishing English as the official language during military control.^[72] On 8 September U.S. Lieutenant General John R. Hodge arrived in Incheon to accept the Japanese surrender south of the 38th parallel.^[69] Appointed as military governor, Hodge directly controlled South Korea as head of the United States Army Military Government in Korea (USAMGIK 1945–48).^[73]

In December 1945, Korea was administered by a U.S.–Soviet Union Joint Commission, as agreed at the Moscow Conference, with the aim of granting independence after a five-year trusteeship.^[74][75] The idea (to have to wait 5 years for independence) was not popular among Koreans, and riots broke out.^[58] To contain them, the USAMGIK banned strikes on 8 December and outlawed the PRK Revolutionary Government and the PRK People's Committees on 12 December.^[76] Following further large-scale civilian unrest,^[77] the USAMGIK declared martial law.

Citing the inability of the Joint Commission to make progress, the U.S. government decided to hold an election under United Nations auspices with the aim of creating an independent Korea. The Soviet authorities and the Korean communists refused to co-operate on the grounds that it would not be fair, and many South Korean politicians boycotted it.^[78][79] A general election was held in the South on 10 May 1948.^[80][81] North Korea held parliamentary elections three months later on 25 August.^[82] The resultant South Korean government promulgated a national political constitution on 17 July and elected Syngman Rhee as president on 20 July. The Republic of Korea (South Korea) was established on 15 August 1948. In the Soviet Korean Zone of Occupation, the Soviet Union agreed to the establishment of a communist government^[80] led by Kim Il Sung.^[83]

The Soviet Union withdrew its forces from Korea in 1948, and U.S. troops withdrew in 1949.^[84][85]

Chinese Civil War (1945–1949)

With the end of the war with Japan, the Chinese Civil War resumed in earnest between the Communists and the Nationalist-led government. While the Communists were struggling for supremacy in Manchuria, they were supported by the North Korean government with matériel and manpower.^[86] According to Chinese sources, the North Koreans donated 2,000 railway cars worth of supplies while thousands of Koreans served in the Chinese PLA during the war.^[87] North Korea also provided the Chinese Communists in Manchuria with a safe refuge for non-combatants and communications with the rest of China.^[86]

The North Korean contributions to the Chinese Communist victory were not forgotten after the creation of the People's Republic of China (PRC) in 1949. As a token of gratitude, between 50,000 and 70,000 Korean veterans that served in the PLA were sent back along with their weapons, and they later played a significant role in the initial invasion of South Korea.^[86] China promised to support the North Koreans in the event of a war against South Korea.^[88]

Communist insurgency in South Korea (1948–1950)

By 1948, a large-scale, North Korea-backed insurgency had broken out in the southern half of the peninsula. This was exacerbated by the ongoing undeclared border war between the Koreas, which saw division-level engagements and thousands of deaths on both sides.^[89] The ROK in this time was almost entirely trained and focused on counterinsurgency, rather than conventional warfare. They were equipped and advised by a force of a few hundred American officers, who were largely successful in helping the ROKA to subdue guerrillas and hold its own against North Korean military (Korean People's Army, KPA) forces along the 38th parallel.^[90] Approximately 8,000 South Korean soldiers and police died in the insurgent war and border clashes.^[91]

The first socialist uprising occurred without direct North Korean participation, though the guerrillas still professed support for the northern government. Beginning in April 1948 on the isolated island of Jeju, the campaign saw mass arrests and repression by the South Korean government in the fight against the South Korean Labor Party, resulting in a total of 30,000 violent deaths, among them 14,373 civilians (of whom ~2,000 were killed by rebels and ~12,000 by ROK security forces). The Yeosu–Suncheon rebellion overlapped with it, as several thousand army defectors waving red flags massacred right-leaning families. This resulted in another brutal suppression by the government and between 2,976 and 3,392 deaths. By May 1949, both uprisings had been crushed.

Insurgency reignited in the spring of 1949 when attacks by guerrillas in the mountainous regions (buttressed by army defectors and North Korean agents) increased. Insurgent activity peaked in late 1949 as the ROKA engaged so-called People's Guerrilla Units. Organized and armed by the North Korean government, and backed up by 2,400 KPA commandos who had infiltrated through the border, these guerrillas launched a large offensive in September aimed at undermining the South Korean government and preparing the country for the KPA's arrival in force. This offensive failed.^[92] However, by this point, the guerrillas were firmly entrenched in the Taebaek-san region of the North Gyeongsang Province (around Taegu), as well as in the border areas of the Gangwon Province.^[93]

While the insurgency was ongoing, the ROKA and KPA engaged in multiple battalion-sized battles along the border, starting in May 1949.^[90] Serious border clashes between South and North continued on 4 August 1949, when thousands of North Korean troops attacked South Korean troops occupying territory north of the 38th parallel. The 2nd and 18th ROK Infantry Regiments repulsed initial attacks in Kuksa-bong (above the 38th parallel),^[94] and at the end of the clashes ROK troops were "completely routed".^[95] Border incidents decreased significantly by the start of 1950.^[93]

Meanwhile, counterinsurgency efforts in the South Korean interior intensified; persistent operations, paired with worsening weather conditions, eventually denied the guerrillas sanctuary and wore away their fighting strength. North Korea responded by sending more troops to link up with existing insurgents and build more partisan cadres; the number of North Korean infiltrators had reached 3,000 soldiers in 12 units by the start of 1950, but all of these units were destroyed or scattered by the ROKA.^[96] On 1 October 1949, the ROKA launched a three-pronged assault on the insurgents in South Cholla and Taegu. By March 1950, the ROKA claimed 5,621 guerrillas killed or captured and 1,066 small arms seized. This operation crippled the insurgency. Soon after, the North Koreans made two final attempts to keep the uprising active, sending two battalion-sized units of infiltrators under the commands of Kim Sang-ho and Kim Moo-hyon. The first battalion was reduced in annihilation to a single man over the course of several engagements by the ROKA 8th Division. The second battalion was annihilated by a two-battalion hammer-and-anvil maneuver by units of the ROKA 6th Division, resulting in a loss toll of 584 KPA guerrillas (480 killed, 104 captured) and 69 ROKA troops killed, plus 184 wounded.^[97] By spring of 1950, guerrilla activity had mostly subsided; the border, too, was calm.^[98]

Prelude to war (1950)

By 1949, South Korean and U.S. military actions had reduced the active number of indigenous communist guerrillas in the South from 5,000 to 1,000. However, Kim Il Sung believed that widespread uprisings had weakened the South Korean military and that a North Korean invasion would be welcomed by much of the South Korean population. Kim began seeking Stalin's support for an invasion in March 1949, traveling to Moscow to attempt to persuade him.^[99]

Stalin initially did not think the time was right for a war in Korea. PLA forces were still embroiled in the Chinese Civil War, while U.S. forces remained stationed in South Korea.^[100] By spring 1950, he believed that the strategic situation had changed: PLA forces under Mao Zedong had secured final victory in China, U.S. forces had withdrawn from Korea, and the Soviets had detonated their first nuclear bomb, breaking the U.S. atomic monopoly. As the U.S. had not directly intervened to stop the communist victory in China, Stalin calculated that they would be even less willing to fight in Korea, which had much less strategic significance.^[101] The Soviets had also cracked the codes used by the U.S. to communicate with their embassy in Moscow, and reading these dispatches convinced Stalin that Korea did not have the importance to the U.S. that would warrant a nuclear confrontation.^[101] Stalin began a more aggressive strategy in Asia based on these developments, including promising economic and military aid to China through the Sino-Soviet Treaty of Friendship, Alliance, and Mutual Assistance.^[102]

In April 1950, Stalin gave Kim permission to attack the government in the South under the condition that Mao would agree to send reinforcements if needed.^[103] For Kim, this was the fulfilment of his goal to unite Korea after its division by foreign powers. Stalin made it clear that Soviet forces would not openly engage in combat, to avoid a direct war with the U.S.^[103] Kim met with Mao in May 1950 and differing historical interpretations of the outcome of the meeting have been put forward. According to Barbara Barnouin and Yu Changgeng, Mao agreed to support Kim despite concerns of American intervention, as China desperately needed the economic and military aid promised by the Soviets.^[104] Kathryn Weathersby cites Soviet documents which said Kim secured Mao's support.^[105] Along with Mark O'Neill, she says this accelerated Kim's war preparations.^[106][107] Chen Jian argues Mao never seriously challenged Kim’s plans and that Kim had every reason to inform Stalin that he had obtained Mao's support.^[108]: 112 Citing recent scholarship, Zhao Suisheng contends Mao did not approve of Kim's war proposal and requested verification from Stalin which he provided via a telegram.^{[109]: 28–9} Mao accepted the decision made by Kim and Stalin to unify the Koreas but cautioned Kim over possible US intervention.^[109]: 30

Soviet generals with extensive combat experience from the Second World War were sent to North Korea as the Soviet Advisory Group. These generals completed the plans for the attack by May.^[110] The original plans called for a skirmish to be initiated in the Ongjin Peninsula on the west coast of Korea. The North Koreans would then launch an attack that would capture Seoul and encircle and destroy the ROK. The final stage would involve destroying South Korean government remnants and capturing the rest of South Korea, including the ports.^[111]

On 7 June 1950, Kim called for a Korea-wide election on 5–8 August 1950 and a consultative conference in Haeju on 15–17 June. On 11 June, the North sent three diplomats to the South as a peace overture which Rhee rejected outright.^[103] On 21 June, Kim revised his war plan to involve a general attack across the 38th parallel, rather than a limited operation in the Ongjin Peninsula. Kim was concerned that South Korean agents had learned about the plans and that South Korean forces were strengthening their defenses. Stalin agreed to this change of plan.^[112]

While these preparations were underway in the North, there were frequent clashes along the 38th parallel, especially at Kaesong and Ongjin, many initiated by the South.^[37][38] The ROK was being trained by the U.S. Korean Military Advisory Group (KMAG). On the eve of war, KMAG commander General William Lynn Roberts voiced utmost confidence in the ROK and boasted that any North Korean invasion would merely provide "target practice".^[113] For his part, Syngman Rhee repeatedly expressed his desire to conquer the North, including when U.S. diplomat John Foster Dulles visited Korea on 18 June.^[114]

Although some South Korean and U.S. intelligence officers predicted an attack from the North, similar predictions had been made before and nothing had happened.^[115] The Central Intelligence Agency noted the southward movement by the KPA but assessed this as a "defensive measure" and concluded an invasion was "unlikely".^[116] On 23 June UN observers inspected the border and did not detect that war was imminent.^[117]

Comparison of forces

Throughout 1949 and 1950, the Soviets continued arming North Korea. After the communist victory in the Chinese Civil War, ethnic Korean units in the PLA were sent to North Korea.^[118] Chinese involvement was extensive from the beginning, building on previous collaboration between the Chinese and Korean communists during the Chinese Civil War. In the fall of 1949, two PLA divisions composed mainly of Korean-Chinese troops (the 164th and 166th) entered North Korea, followed by smaller units throughout the rest of 1949; these troops brought with them not only their experience and training, but also their weapons and other equipment, changing little but their uniforms. The reinforcement of the KPA with PLA veterans continued into 1950, with the 156th Division and several other units of the former Fourth Field Army arriving (also with their equipment) in February; the PLA 156th Division was reorganized as the KPA 7th Division. By mid-1950, between 50,000 and 70,000 former PLA troops had entered North Korea, forming a significant part of the KPA's strength on the eve of the war's beginning.^[119] Several generals, such as Lee Kwon-mu, were PLA veterans born to ethnic Koreans in China. The combat veterans and equipment from China, the tanks, artillery and aircraft supplied by the Soviets, and rigorous training increased North Korea's military superiority over the South, armed by the U.S. military with mostly small arms, but no heavy weaponry such as tanks.^[120] While older histories of the conflict often referred to these ethnic Korean PLA veterans as being sent from northern Korea to fight in the Chinese Civil War before being sent back, recent Chinese archival sources studied by Kim Donggill indicate that this was not the case. Rather, the soldiers were indigenous to China (part of China's longstanding ethnic Korean community) and were recruited to the PLA in the same way as any other Chinese citizen.^[121]

According to the first official census in 1949, the population of North Korea numbered 9,620,000,^[122] and by mid-1950, North Korean forces numbered between 150,000 and 200,000 troops, organized into 10 infantry divisions, one tank division, and one air force division, with 210 fighter planes and 280 tanks, who captured scheduled objectives and territory, among them Kaesong, Chuncheon, Uijeongbu and Ongjin. Their forces included 274 T-34-85 tanks, 200 artillery pieces, 110 attack bombers, and some 150 Yak fighter planes, and 35 reconnaissance aircraft. In addition to the invasion force, the North had 114 fighters, 78 bombers, 105 T-34-85 tanks, and some 30,000 soldiers stationed in reserve in North Korea.^[69] Although each navy consisted of only several small warships, the North and South Korean navies fought in the war as seaborne artillery for their armies.

In contrast, the South Korean population was estimated at 20 million,^[123] but its army was unprepared and ill-equipped. As of 25 June 1950, the ROK had 98,000 soldiers (65,000 combat, 33,000 support), no tanks (they had been requested from the U.S. military, but requests were denied), and a 22-plane air force comprising 12 liaison-type and 10 AT-6 advanced-trainer airplanes. Large U.S. garrisons and air forces were in Japan,^[124] but only 200–300 U.S. troops were in Korea.^[125]

Operation Pokpung

At dawn on 25 June 1950, the KPA crossed the 38th parallel behind artillery fire.^[126] The KPA justified its assault with the claim that ROK troops attacked first and that the KPA were aiming to arrest and execute the "bandit traitor Syngman Rhee".^[127] Fighting began on the strategic Ongjin Peninsula in the west.^[128][129] There were initial South Korean claims that the 17th Regiment had counterattacked at Haeju; some scholars argue the claimed counterattack was instead the instigating attack, and therefore that the South Koreans may have fired first.^[128][130] However, the report that contained the Haeju claim also contained numerous other errors and outright falsehoods.^[131]

Whoever fired the first shots in Ongjin, KPA forces attacked all along the 38th parallel within an hour. The KPA had a combined arms force including tanks supported by heavy artillery. The ROK had no tanks, anti-tank weapons or heavy artillery to stop such an attack. In addition, the South Koreans committed their forces in a piecemeal fashion, and these were routed in a few days.^[132]

On 27 June, Rhee evacuated Seoul with some of the government. At 02:00 on 28 June the ROK blew up the Hangang Bridge across the Han River in an attempt to stop the KPA. The bridge was detonated while 4,000 refugees were crossing it, and hundreds were killed.^[133][134] Destroying the bridge also trapped many ROK units north of the Han River.^[132] In spite of such desperate measures, Seoul fell that same day. A number of South Korean National Assemblymen remained in Seoul when it fell, and 48 subsequently pledged allegiance to the North.^[135]

On 28 June, Rhee ordered the massacre of suspected political opponents in his own country.^[136] In five days, the ROK, which had 95,000 troops on 25 June, was down to less than 22,000 troops. In early July, when U.S. forces arrived, what was left of the ROK was placed under U.S. operational command of the United Nations Command.^[137]

Factors in U.S. intervention

The Truman administration was unprepared for the invasion. Korea was not included in the strategic Asian Defense Perimeter outlined by United States Secretary of State Dean Acheson.^[138] Military strategists were more concerned with the security of Europe against the Soviet Union than East Asia.^[139] At the same time, the administration was worried that a war in Korea could quickly escalate without American intervention. Said diplomat John Foster Dulles in a cable: "To sit by while Korea is overrun by unprovoked armed attack would start a disastrous chain of events leading most probably to world war."^[140]

While there was initial hesitance by some in the U.S. government to get involved in the war, considerations about Japan played a part in the ultimate decision to engage on behalf of South Korea. Especially after the fall of China to the communists, U.S. experts on East Asia saw Japan as the critical counterweight to the Soviet Union and China in the region. While there was no U.S. policy dealing with South Korea directly as a national interest, its proximity to Japan increased the importance of South Korea. Said Kim: "The recognition that the security of Japan required a non-hostile Korea led directly to President Truman's decision to intervene ... The essential point ... is that the American response to the North Korean attack stemmed from considerations of U.S. policy toward Japan."^[141][142]

Another major consideration was the possible Soviet reaction if the U.S. intervened. The Truman administration was fearful that a war in Korea was a diversionary assault that would escalate to a general war in Europe once the United States committed in Korea. At the same time, "[t]here was no suggestion from anyone that the United Nations or the United States could back away from [the conflict]".^[143] Yugoslavia—a possible Soviet target because of the Tito-Stalin split—was vital to the defense of Italy and Greece, and the country was first on the list of the National Security Council's post-North Korea invasion list of "chief danger spots".^[144] Truman believed if aggression went unchecked, a chain reaction would be initiated that would marginalize the UN and encourage communist aggression elsewhere. The UN Security Council approved the use of force to help the South Koreans, and the U.S. immediately began using air and naval forces that were in the area to that end. The Truman administration still refrained from committing troops on the ground because some advisers believed the North Koreans could be stopped by air and naval power alone.^[145]

The Truman administration was still uncertain if the attack was a ploy by the Soviet Union or just a test of U.S. resolve. The decision to commit ground troops became viable when a communiqué was received on 27 June indicating the Soviet Union would not move against U.S. forces in Korea.^[146] The Truman administration believed it could intervene in Korea without undermining its commitments elsewhere.

United Nations Security Council resolutions

On 25 June 1950, the United Nations Security Council unanimously condemned the North Korean invasion of South Korea with UN Security Council Resolution 82. The Soviet Union, a veto-wielding power, had boycotted the Council meetings since January 1950, protesting Taiwan's occupation of China's permanent seat in the UN Security Council.^[147] After debating the matter, the Security Council, on 27 June 1950, published Resolution 83 recommending member states provide military assistance to the Republic of Korea. On 27 June President Truman ordered U.S. air and sea forces to help South Korea. On 4 July the Soviet deputy foreign minister accused the U.S. of starting armed intervention on behalf of South Korea.^[148]

The Soviet Union challenged the legitimacy of the war for several reasons. The ROK intelligence upon which Resolution 83 was based came from U.S. Intelligence; North Korea was not invited as a sitting temporary member of the UN, which violated UN Charter Article 32; and the fighting was beyond the UN Charter's scope, because the initial north–south border fighting was classed as a civil war. Because the Soviet Union was boycotting the Security Council at the time, legal scholars posited that deciding upon an action of this type required the unanimous vote of all the five permanent members including the Soviet Union.^[149][150]

Within days of the invasion, masses of ROK soldiers—of dubious loyalty to the Syngman Rhee regime—were retreating southwards or defecting en masse to the northern side, the KPA.^[60]

United States' response (July–August 1950)

A U.S. howitzer position near the Kum River, 15 July

Man of the Year, the American soldier on Time magazine cover, 1951

As soon as word of the attack was received,^[151] Acheson informed President Truman that the North Koreans had invaded South Korea.^[152][153] Truman and Acheson discussed a U.S. invasion response and agreed that the U.S. was obligated to act, comparing the North Korean invasion with Adolf Hitler's aggressions in the 1930s, with the conclusion being that the mistake of appeasement must not be repeated.^[154] Several U.S. industries were mobilized to supply materials, labor, capital, production facilities, and other services necessary to support the military objectives of the Korean War.^[155] Truman later explained that he believed fighting the invasion was essential to the U.S. goal of the global containment of communism as outlined in the National Security Council Report 68 (NSC 68) (declassified in 1975):

Communism was acting in Korea, just as Hitler, Mussolini and the Japanese had ten, fifteen, and twenty years earlier. I felt certain that if South Korea was allowed to fall, Communist leaders would be emboldened to override nations closer to our own shores. If the Communists were permitted to force their way into the Republic of Korea without opposition from the free world, no small nation would have the courage to resist threat and aggression by stronger Communist neighbors.^[156]

In August 1950, Truman and Acheson obtained the consent of Congress to appropriate $12 billion for military action in Korea, equivalent to $146 billion in 2022.^[153] Because of the extensive defense cuts and the emphasis placed on building a nuclear bomber force, none of the services were in a position to make a robust response with conventional military strength. General Omar Bradley, Chairman of the Joint Chiefs of Staff, was faced with reorganizing and deploying a U.S. military force that was a shadow of its World War II counterpart.^[157][158]

Acting on Acheson's recommendation, Truman ordered Supreme Commander for the Allied Powers in Japan General Douglas MacArthur to transfer matériel to the South Korean military while giving air cover to the evacuation of U.S. nationals. Truman disagreed with advisers who recommended unilateral bombing of the North Korean forces and ordered the U.S. Seventh Fleet to protect the Republic of China (Taiwan), whose government asked to fight in Korea. The United States denied Taiwan's request for combat, lest it provoke a PRC retaliation.^[159] Because the United States had sent the Seventh Fleet to "neutralize" the Taiwan Strait, Chinese Premier Zhou Enlai criticized both the UN and U.S. initiatives as "armed aggression on Chinese territory".^[160]

The drive south and Pusan (July–September 1950)

G.I. comforting a grieving infantryman

Crew of an M-24 tank along the Nakdong River front, August 1950

The Battle of Osan, the first significant U.S. engagement of the Korean War, involved the 540-soldier Task Force Smith, which was a small forward element of the 24th Infantry Division which had been flown in from Japan.^[161] On 5 July 1950, Task Force Smith attacked the KPA at Osan but without weapons capable of destroying the KPA tanks. The KPA defeated the U.S. soldiers; the result was 180 American casualties. The KPA progressed southwards, pushing back U.S. forces at Pyongtaek, Chonan, and Chochiwon, forcing the 24th Division's retreat to Taejeon, which the KPA captured in the Battle of Taejon; the 24th Division suffered 3,602 dead and wounded and 2,962 captured, including its commander, Major General William F. Dean.^[162]

By August, the KPA steadily pushed back the ROK and the Eighth United States Army southwards.^[163] The impact of the Truman administration's defense budget cutbacks was now keenly felt, as U.S. troops fought a series of costly rearguard actions. Facing a veteran and well-led KPA force, and lacking sufficient anti-tank weapons, artillery or armor, the Americans retreated and the KPA advanced down the Korean Peninsula.^[164][165] During their advance, the KPA purged South Korea's intelligentsia by killing civil servants and intellectuals. On 20 August, MacArthur warned Kim Il Sung that he would be held responsible for the KPA's atrocities.^[166] By September, UN forces were hemmed into a small corner of southeast Korea, near Pusan. This 230-kilometre (140-mile) perimeter enclosed about 10% of Korea, in a line partially defined by the Nakdong River.

Although Kim's early successes led him to predict he would end the war by the end of August, Chinese leaders were more pessimistic. To counter a possible U.S. deployment, Zhou secured a Soviet commitment to have the Soviet Union support Chinese forces with air cover, and he deployed 260,000 soldiers along the Korean border, under the command of Gao Gang. Zhou authorized a topographical survey of Korea and directed Lei Yingfu, Zhou's military adviser in Korea, to analyze the military situation in Korea. Lei concluded that MacArthur would most likely attempt a landing at Incheon.^[167][168] After conferring with Mao that this would be MacArthur's most likely strategy, Zhou briefed Soviet and North Korean advisers of Lei's findings, and issued orders to PLA commanders deployed on the Korean border to prepare for U.S. naval activity in the Korea Strait.^[169]

In the resulting Battle of Pusan Perimeter (August–September 1950), the UN forces withstood KPA attacks meant to capture the city at the Naktong Bulge, P'ohang-dong, and Taegu. The United States Air Force (USAF) interrupted KPA logistics with 40 daily ground support sorties, which destroyed 32 bridges, halting most daytime road and rail traffic. KPA forces were forced to hide in tunnels by day and move only at night.^[170] To deny military equipment and supplies to the KPA, the USAF destroyed logistics depots, petroleum refineries, and harbors, while the U.S. Navy aircraft attacked transport hubs. Consequently, the overextended KPA could not be supplied throughout the south.^[171] On 27 August, 67th Fighter Squadron aircraft mistakenly attacked facilities in Chinese territory, and the Soviet Union called the UN Security Council's attention to China's complaint about the incident.^[172] The U.S. proposed that a commission of India and Sweden determine what the U.S. should pay in compensation, but the Soviets vetoed the U.S. proposal.^[173][174]

Meanwhile, U.S. garrisons in Japan continually dispatched soldiers and military supplies to reinforce defenders in the Pusan Perimeter.^[175] MacArthur went so far as to call for Japan's rearmament.^[176] Tank battalions deployed to Korea directly from the U.S. mainland from the port of San Francisco to the port of Pusan, the largest Korean port. By late August, the Pusan Perimeter had some 500 medium tanks battle-ready.^[177] In early September 1950, UN forces outnumbered the KPA 180,000 to 100,000 soldiers.^[57][178]

Battle of Incheon (September 1950)

General Douglas MacArthur, UN Command CiC (seated), observes the naval shelling of Incheon from USS Mount McKinley, 15 September 1950

Combat in the streets of Seoul

Pershing tanks in downtown Seoul during the Second Battle of Seoul in September 1950. In the foreground, United Nations troops round up North Korean prisoners-of-war.

Against the rested and rearmed Pusan Perimeter defenders and their reinforcements, the KPA were undermanned and poorly supplied; unlike the UN forces, they lacked naval and air support.^[179] To relieve the Pusan Perimeter, MacArthur recommended an amphibious landing at Incheon, near Seoul and well over 160 km (100 mi) behind the KPA lines.^[180] On 6 July, he ordered Major General Hobart R. Gay, commander of the U.S. 1st Cavalry Division, to plan the division's amphibious landing at Incheon; on 12–14 July, the 1st Cavalry Division embarked from Yokohama, Japan, to reinforce the 24th Infantry Division inside the Pusan Perimeter.^[181]

Soon after the war began, MacArthur began planning a landing at Incheon, but the Pentagon opposed him.^[180] When authorized, he activated a combined U.S. Army and Marine Corps, and ROK force. The X Corps, led by Major General Edward Almond, consisted of 40,000 troops of the 1st Marine Division, the 7th Infantry Division and around 8,600 ROK soldiers.^[182] By 15 September, the amphibious assault force faced few KPA defenders at Incheon: military intelligence, psychological warfare, guerrilla reconnaissance, and protracted bombardment facilitated a relatively light battle. However, the bombardment destroyed most of Incheon.^[183]

Breakout from the Pusan Perimeter

On 16 September Eighth Army began its breakout from the Pusan Perimeter. Task Force Lynch,^[184][185] 3rd Battalion, 7th Cavalry Regiment, and two 70th Tank Battalion units (Charlie Company and the Intelligence–Reconnaissance Platoon) advanced through 171.2 km (106.4 mi) of KPA territory to join the 7th Infantry Division at Osan on 27 September.^[181] X Corps rapidly defeated the KPA defenders around Seoul, thus threatening to trap the main KPA force in southern Korea.^[186]

On 18 September, Stalin dispatched General H. M. Zakharov to North Korea to advise Kim to halt his offensive around the Pusan Perimeter and to redeploy his forces to defend Seoul. Chinese commanders were not briefed on North Korean troop numbers or operational plans. As the overall commander of Chinese forces, Zhou suggested that the North Koreans should attempt to eliminate the UN forces at Incheon only if they had reserves of at least 100,000 men; otherwise, he advised the North Koreans to withdraw their forces north.^[187]

On 25 September, Seoul was recaptured by UN forces. U.S. air raids caused heavy damage to the KPA, destroying most of its tanks and much of its artillery. KPA troops in the south, instead of effectively withdrawing north, rapidly disintegrated, leaving Pyongyang vulnerable.^[187] During the general retreat, only 25,000 to 30,000 KPA soldiers managed to reach the KPA lines.^[188][189] On 27 September, Stalin convened an emergency session of the Politburo, in which he condemned the incompetence of the KPA command and held Soviet military advisers responsible for the defeat.^[187]

UN forces invade North Korea (September–October 1950)

On 27 September, MacArthur received the top secret National Security Council Memorandum 81/1 from Truman reminding him that operations north of the 38th parallel were authorized only if "at the time of such operation there was no entry into North Korea by major Soviet or Chinese Communist forces, no announcements of intended entry, nor a threat to counter our operations militarily".^[190] On 29 September, MacArthur restored the government of the Republic of Korea under Syngman Rhee.^[187] The Joint Chiefs of Staff on 27 September sent to MacArthur a comprehensive directive to govern his future actions: the directive stated that the primary goal was the destruction of the KPA, with unification of the Korean Peninsula under Rhee as a secondary objective "if possible"; the Joint Chiefs added that this objective was dependent on whether the Chinese and Soviets would intervene, and was subject to changing conditions.^[191]

U.S. Air Force attacking railroads south of Wonsan on the eastern coast of North Korea

On 30 September, Zhou warned the U.S. that China was prepared to intervene in Korea if the U.S. crossed the 38th parallel. Zhou attempted to advise KPA commanders on how to conduct a general withdrawal by using the same tactics that allowed Chinese communist forces to successfully escape Chiang Kai-shek's encirclement campaigns in the 1930s, but by some accounts, KPA commanders did not use these tactics effectively.^[192] Historian Bruce Cumings argues, however, that the KPA's rapid withdrawal was strategic, with troops melting into the mountains from where they could launch guerrilla raids on the UN forces spread out on the coasts.^[193]

Refugees flee over the top of a broken bridge in Pyongyang (4 December 1950)

By 1 October the UN Command had repelled the KPA northwards past the 38th parallel; the ROK advanced after them into North Korea.^[194] MacArthur made a statement demanding the KPA's unconditional surrender.^[195] Six days later, on 7 October, with UN authorization, the UN Command forces followed the ROK forces northwards.^[196] The Eighth U.S. Army drove up western Korea and captured Pyongyang on 19 October.^[197] The 187th Airborne Regimental Combat Team made their first of two combat jumps during the Korean War on 20 October at Sunchon and Sukchon. The mission was to cut the road north going to China, preventing North Korean leaders from escaping from Pyongyang; and to rescue U.S. prisoners of war.

At month's end, UN forces held 135,000 KPA prisoners of war. As they neared the Sino-Korean border, the UN forces in the west were divided from those in the east by 80–161 km (50–100 mi) of mountainous terrain.^[198] In addition to the 135,000 captured, the KPA had also suffered some 200,000 soldiers killed or wounded for a total of 335,000 casualties since the end of June 1950, and had lost 313 tanks (mostly T-34/85 models). A mere 25,000 KPA regulars retreated across the 38th parallel, as their military had entirely collapsed. The UN forces on the peninsula numbered 229,722 combat troops (including 125,126 Americans and 82,786 South Koreans), 119,559 rear area troops, and 36,667 U.S. Air Force personnel.^[199] Taking advantage of the UN Command's strategic momentum against the communists, MacArthur believed it necessary to extend the Korean War into China to destroy depots supplying the North Korean war effort. Truman disagreed and ordered caution at the Sino-Korean border.^[200]

China intervenes (October–December 1950)

Chinese forces cross the frozen Yalu River.

On 3 October 1950, China attempted to warn the United States by way of its embassy in India that it would intervene if UN forces crossed the Yalu River.^{[201]: 42 [108]: 169} The United States did not respond as policymakers in Washington, including Truman, considered the warning to be a bluff.^{[201]: 42 [108]: 169 [202]: 57}

On 15 October Truman and MacArthur met at Wake Island. This meeting was much publicized because of MacArthur's discourteous refusal to meet the president in the continental United States.^[203] To Truman, MacArthur speculated there was little risk of Chinese intervention in Korea,^[204] and that the PRC's opportunity for aiding the KPA had lapsed. He believed the PRC had some 300,000 soldiers in Manchuria and some 100,000–125,000 soldiers at the Yalu River. He further concluded that, although half of those forces might cross south, "if the Chinese tried to get down to Pyongyang, there would be the greatest slaughter" without Soviet air force protection.^[188][205]

Meanwhile on 13 October, the Politburo decided that China would intervene even in the absence of Soviet air support, basing its decision on a belief that superior morale could defeat an enemy that had superior equipment.^[206] To that end, 200,000 People's Volunteer Army (PVA) troops crossed the Yalu into North Korea.^[207] UN aerial reconnaissance had difficulty sighting PVA units in daytime, because their march and bivouac discipline minimized aerial detection.^[208] The PVA marched "dark-to-dark" (19:00–03:00), and aerial camouflage (concealing soldiers, pack animals, and equipment) was deployed by 05:30. Meanwhile, daylight advance parties scouted for the next bivouac site. During daylight activity or marching, soldiers were to remain motionless if an aircraft appeared, until it flew away;^[208] PVA officers were under order to shoot security violators. Such battlefield discipline allowed a three-division army to march the 460 km (286 mi) from An-tung, Manchuria, to the combat zone in some 19 days. Another division night-marched a circuitous mountain route, averaging 29 km (18 mi) daily for 18 days.^[69]

Soldiers from the US 2nd Infantry Division in action near the Ch'ongch'on River (20 November 1950).

Map of the UN retreat in the wake of Chinese intervention.

After secretly crossing the Yalu River on 19 October, the PVA 13th Army Group launched the First Phase Offensive on 25 October, attacking the advancing UN forces near the Sino-Korean border. This military decision made solely by China changed the attitude of the Soviet Union. Twelve days after PVA troops entered the war, Stalin allowed the Soviet Air Forces to provide air cover and supported more aid to China.^[209] After inflicting heavy losses on the ROK II Corps at the Battle of Onjong, the first confrontation between Chinese and U.S. military occurred on 1 November 1950. Deep in North Korea, thousands of soldiers from the PVA 39th Army encircled and attacked the U.S. 8th Cavalry Regiment with three-prong assaults—from the north, northwest, and west—and overran the defensive position flanks in the Battle of Unsan.^[210]

On 13 November, Mao appointed Zhou the overall commander and coordinator of the war effort, with Peng Dehuai as field commander.^[207] On 25 November, on the Korean western front, the PVA 13th Army Group attacked and overran the ROK II Corps at the Battle of the Ch'ongch'on River, and then inflicted heavy losses on the U.S. 2nd Infantry Division on the UN forces' right flank.^[211] Believing that they could not hold against the PVA, the Eighth Army began to retreat from North Korea crossing the 38th parallel in mid-December.^[212]

In the east, on 27 November, the PVA 9th Army Group initiated the Battle of Chosin Reservoir. Here, the UN forces fared comparatively better: like the Eighth Army, the surprise attack also forced X Corps to retreat from northeast Korea, but they were, in the process, able to break out from the attempted encirclement by the PVA and execute a successful tactical withdrawal. X Corps managed to establish a defensive perimeter at the port city of Hungnam on 11 December and were able to evacuate by 24 December to reinforce the badly depleted Eighth Army to the south.^[213][214] During the evacuation, about 193 shiploads of UN forces and matériel (approximately 105,000 soldiers, 98,000 civilians, 17,500 vehicles, and 350,000 tons of supplies) were evacuated to Pusan.^[215] The SS Meredith Victory was noted for evacuating 14,000 refugees, the largest rescue operation by a single ship, even though it was designed to hold 12 passengers. Before escaping, the UN forces razed most of Hungnam city, with particular attention to the port facilities.^[188][216]

In early December UN forces, including the British Army's 29th Infantry Brigade, evacuated Pyongyang along with large numbers of refugees.^[217] Around 4.5 million North Koreans are estimated to have fled from North Korea to either the South or elsewhere abroad.^[218] On 16 December Truman declared a national state of emergency with Presidential Proclamation No. 2914, 3 C.F.R. 99 (1953),^[219] which remained in force until 14 September 1978.^{[lower-alpha 4]} The next day, 17 December, Kim Il Sung was deprived of the right of command of KPA by China.^[220]

Fighting around the 38th parallel (January–June 1951)

A ceasefire presented by the UN to the PRC shortly after the Battle of the Ch'ongch'on River on 11 December was rejected by the Chinese government, which was convinced of the PVA's invincibility after its victory in that battle and the wider Second Phase Offensive.^[221][222] With Lieutenant General Matthew Ridgway assuming the command of the Eighth Army on 26 December, the PVA and the KPA launched their Third Phase Offensive (also known as the "Chinese New Year's Offensive") on New Year's Eve of 1950/51. Utilizing night attacks in which UN fighting positions were encircled and then assaulted by numerically superior troops who had the element of surprise, the attacks were accompanied by loud trumpets and gongs, which fulfilled the double purpose of facilitating tactical communication and mentally disorienting the enemy. UN forces initially had no familiarity with this tactic, and as a result, some soldiers panicked, abandoning their weapons and retreating to the south.^[223] The offensive overwhelmed UN forces, allowing the PVA and KPA to capture Seoul for the second time on 4 January 1951.

B-26 Invaders bomb logistics depots in Wonsan, North Korea, 1951

These setbacks prompted General MacArthur to consider using nuclear weapons against the Chinese or North Korean interiors, intending radioactive fallout zones to interrupt the Chinese supply chains.^[224] However, upon the arrival of the charismatic General Ridgway, the esprit de corps of the bloodied Eighth Army immediately began to revive.^[225]

UN forces retreated to Suwon in the west, Wonju in the center, and the territory north of Samcheok in the east, where the battlefront stabilized and held.^[223] The PVA had outrun its logistics capability and thus were unable to press on beyond Seoul as food, ammunition, and matériel were carried nightly, on foot and bicycle, from the border at the Yalu River to the three battle lines.^[226] On 25 late January, upon finding that the PVA had abandoned their battle lines, Ridgway ordered a reconnaissance-in-force, which became Operation Thunderbolt.^[227] A full-scale advance fully exploited the UN's air superiority,^[228] concluding with the UN forces reaching the Han River and recapturing Wonju.^[227]

Following the failure of ceasefire negotiations in January, the United Nations General Assembly passed Resolution 498 on 1 February, condemning the PRC as an aggressor, and called upon its forces to withdraw from Korea.^[229][230]

In early February, the ROK 11th Division ran an operation to destroy guerrillas and pro-DPRK sympathizers in the South Gyeongsang Province.^[231] During the operation, the division and police committed the Geochang and Sancheong–Hamyang massacres.^[231] In mid-February, the PVA counterattacked with the Fourth Phase Offensive and achieved initial victory at Hoengseong. However, the offensive was blunted by U.S. IX Corps at Chipyong-ni in the center.^[227] The U.S. 23rd Regimental Combat Team and the French Battalion fought a short but desperate battle that broke the attack's momentum.^[227] The battle is sometimes known as the "Gettysburg of the Korean War": 5,600 U.S., and French troops were surrounded on all sides by 25,000 PVA. UN forces had previously retreated in the face of large PVA/KPA forces instead of getting cut off, but this time, they stood and fought, and won.^[232]

U.S. Marines move out over rugged mountain terrain while closing with North Korean forces.

In the last two weeks of February 1951, Operation Thunderbolt was followed by Operation Killer, carried out by the revitalized Eighth Army. It was a full-scale, battlefront-length attack staged for maximum exploitation of firepower to kill as many KPA and PVA troops as possible.^[227] Operation Killer concluded with U.S. I Corps re-occupying the territory south of the Han River, and IX Corps capturing Hoengseong.^[233] On 7 March the Eighth Army attacked with Operation Ripper, expelling the PVA and the KPA from Seoul on 14 March. This was the fourth and final conquest of the city in a year's time, leaving it a ruin; the 1.5 million pre-war population was down to 200,000, and people were suffering from severe food shortages.^[233][189]

On 1 March Mao sent a cable to Stalin emphasizing the difficulties faced by Chinese forces and the need for air cover, especially over supply lines. Apparently impressed by the Chinese war effort, Stalin agreed to supply two air force divisions, three anti-aircraft divisions, and 6,000 trucks. PVA troops in Korea continued to suffer severe logistical problems throughout the war.

In late April, Peng sent his deputy, Hong Xuezhi, to brief Zhou in Beijing. What Chinese soldiers feared, Hong said, was not the enemy, but having no food, bullets, or trucks to transport them to the rear when they were wounded. Zhou attempted to respond to the PVA's logistical concerns by increasing Chinese production and improving supply methods, but these efforts were never sufficient. At the same time, large-scale air defense training programs were carried out, and the People's Liberation Army Air Force (PLAAF) began participating in the war from September 1951 onward.^[234] The Fourth Phase Offensive had catastrophically failed, in contrast to the success of the Second Phase Offensive and limited gains of the Third Phase Offensive. The UN forces, after earlier defeats and subsequent retraining, proved much harder to infiltrate by Chinese light infantry than they had been in previous months. From 31 January to 21 April, the Chinese had suffered 53,000 casualties.^[235]

On 11 April Truman relieved General MacArthur as supreme commander in Korea.^[236] There were several reasons for the dismissal. MacArthur had crossed the 38th parallel in the mistaken belief that the Chinese would not enter the war, leading to major allied losses. He believed that the use of nuclear weapons should be his decision, not the president's.^[237] MacArthur threatened to destroy China unless it surrendered. While MacArthur felt total victory was the only honorable outcome, Truman was more pessimistic about his chances once involved in a larger war, feeling that a truce and orderly withdrawal from Korea could be a valid solution.^[238] MacArthur was the subject of congressional hearings in May and June 1951, which determined that he had defied the orders of the president and thus had violated the U.S. Constitution.^[239] A popular criticism of MacArthur was that he never spent a night in Korea and directed the war from the safety of Tokyo.^[240]

British UN troops advance alongside a Centurion tank, March 1951

Ridgway was appointed supreme commander in Korea, and he regrouped the UN forces for successful counterattacks,^[241] while General James Van Fleet assumed command of the Eighth Army.^[242] Further attacks slowly depleted the PVA and KPA forces; Operations Courageous (23–28 March) and Tomahawk (23 March) (a combat jump by the 187th Airborne Regimental Combat Team) were joint ground and airborne infiltrations meant to trap PVA forces between Kaesong and Seoul. UN forces advanced to the Kansas Line, north of the 38th parallel.^[243]

The PVA counterattacked in April 1951, with the Fifth Phase Offensive, with three field armies (approximately 700,000 men).^[244] The first thrust of the offensive fell upon I Corps, which fiercely resisted in the Battle of the Imjin River (22–25 April) and the Battle of Kapyong (22–25 April), blunting the impetus of the offensive, which was halted at the No-name Line north of Seoul.^[245] Casualty ratios were grievously disproportionate; Peng had expected a 1:1 or 2:1 ratio, but instead, Chinese combat casualties from 22 to 29 April totaled between 40,000 and 60,000 compared to only 4,000 for the UN —a casualty ratio between 10:1 and 15:1.^[246] By the time Peng had called off the attack in the western sector on 29 April, the three participating armies had lost a third of their front-line combat strength within a week.^[247] Additional casualties were incurred on 30 April. On 15 May the PVA commenced the second impulse of the spring offensive and attacked the ROK and U.S. X Corps in the east at the Soyang River. Approximately 370,000 PVA and 114,000 KPA troops had been mobilized, with the bulk attacking in the eastern sector with about a quarter attempting to pin the I Corps and IX Corps in the western sector. After initial success, they were halted by 20 May and repulsed over the following days, with Western histories generally designating 22 May as the end of the offensive.^[248][249]

At month's end, the Chinese planned the third step of the Fifth Phase Offensive (withdrawal), which they estimated would take 10 to 15 days to complete for their 340,000 remaining men, and set the retreat date for the night of 23 May. They were caught off guard when the Eighth Army counterattacked and regained the Kansas Line on the morning of 12 May, 23 hours before the expected withdrawal.^[250][251] The surprise attack turned the retreat into "the most severe loss since our forces had entered Korea"; from 16 May to 23 May, the PVA suffered another 45,000 to 60,000 casualties before their remaining soldiers managed to evacuate back north.^[251] Per official Chinese statistics, the Fifth Phase Offensive as a whole had cost the PVA 102,000 soldiers (85,000 killed/wounded, 17,000 captured), with unknown but significant losses for the KPA.^[252]

The end of the Fifth Phase Offensive preceded the start of the UN May–June 1951 counteroffensive. During the counteroffensive, the U.S.-led coalition captured land up to about 10 km (6 mi) north of the 38th parallel, with most forces stopping at the Kansas Line and a minority going further to the Wyoming Line. PVA and KPA forces suffered greatly during this offensive, especially in the Chuncheon sector and at Chiam-ni and Hwacheon; in the latter sector alone the PVA/KPA suffered over 73,207 casualties, including 8,749 captured, compared to 2,647 total casualties of the IX Corps which engaged them.^[253]

The halt at the Kansas Line and subsequent offensive action stand-down began the stalemate that lasted until the armistice of 1953. The disastrous failure of the Fifth Phase Offensive (which Peng later recalled as one of only four mistakes he made in his military career) "led Chinese leaders to change their goal from driving the UNF out of Korea to merely defending China's security and ending the war through negotiations".^[254]

Stalemate (July 1951–July 1953)

For the remainder of the war, the UN and the PVA/KPA fought but exchanged little territory, as the stalemate held. Large-scale bombing of North Korea continued, and protracted armistice negotiations began on 10 July 1951 at Kaesong in the North.^[255] On the Chinese side, Zhou directed peace talks, and Li Kenong and Qiao Guanghua headed the negotiation team.^[234] Combat continued while the belligerents negotiated; the goal of the UN forces was to recapture all of South Korea and to avoid losing territory.^[256] The PVA and the KPA attempted similar operations and later effected military and psychological operations to test the UN Command's resolve to continue the war.

The two sides constantly traded artillery fire along the front, with American-led forces possessing a large firepower advantage over the Chinese-led forces. For example, in the last three months of 1952 the UN fired 3,553,518 field gun shells and 2,569,941 mortar shells, while the communists fired 377,782 field gun shells and 672,194 mortar shells: an overall 5.83:1 ratio in the UN's favor.^[257] The communist insurgency, reinvigorated by North Korean support and scattered bands of KPA stragglers, also resurged in the south.

In the autumn of 1951, Eighth Army Commander General James Van Fleet ordered Major General Paik Sun-yup to break the back of guerrilla activity. From December 1951 to March 1952, ROK security forces claimed to have killed 11,090 partisans and sympathizers and captured 9,916 more.^[91]

U.S. M46 Patton tanks, painted with tiger heads thought to demoralize Chinese forces

PVA troops suffered from deficient military equipment, serious logistical problems, overextended communication and supply lines, and the constant threat of UN bombers. All of these factors generally led to a rate of Chinese casualties that was far greater than the casualties suffered by UN troops. The situation became so serious that in November 1951 Zhou called a conference in Shenyang to discuss the PVA's logistical problems. At the meeting, it was decided to accelerate the construction of railways and airfields in the area to increase the number of trucks available to the army, and to improve air defense by any means possible. These commitments did little to address the problems directly that confronted PVA troops.^[258]

New Zealand artillery crew in action, 1952

In the months after the Shenyang conference, Peng went to Beijing several times to brief Mao and Zhou about the heavy casualties suffered by Chinese troops and the increasing difficulty of keeping the front lines supplied with basic necessities. Peng was convinced that the war would be protracted and that neither side would be able to achieve victory in the near future. On 24 February 1952, the Military Commission, presided over by Zhou, discussed the PVA's logistical problems with members of various government agencies involved in the war effort. After the government representatives emphasized their inability to meet the demands of the war, Peng, in an angry outburst, shouted: "You have this and that problem... You should go to the front and see with your own eyes what food and clothing the soldiers have! Not to speak of the casualties! For what are they giving their lives? We have no aircraft. We have only a few guns. Transports are not protected. More and more soldiers are dying of starvation. Can't you overcome some of your difficulties?" The atmosphere became so tense that Zhou was forced to adjourn the conference. Zhou subsequently called a series of meetings, where it was agreed that the PVA would be divided into three groups, to be dispatched to Korea in shifts; to accelerate the training of Chinese pilots; to provide more anti-aircraft guns to the front lines; to purchase more military equipment and ammunition from the Soviet Union; to provide the army with more food and clothing; and to transfer the responsibility of logistics to the central government.^[259]

With peace negotiations ongoing, the Chinese attempted one final offensive in the final weeks of the war to capture territory: on 10 June, 30,000 Chinese troops struck two South Korean and one U.S. divisions on a 13 km (8 mi) front, and on 13 July, 80,000 Chinese soldiers struck the east-central Kumsong sector, with the brunt of their attack falling on four South Korean divisions. In both cases, the Chinese had some success in penetrating South Korean lines but failed to capitalize, particularly when the U.S. forces present responded with overwhelming firepower. Chinese casualties in their final major offensive of the war (above normal wastage for the front) were about 72,000, including 25,000 killed in action compared to 14,000 for the UN (the vast majority of these deaths were South Koreans, though 1,611 were Americans).^[260]

Armistice (July 1953–November 1954)

Men from the Royal Australian Regiment, June 1953

The on-again, off-again armistice negotiations continued for two years,^[261] first at Kaesong then at the neighboring village of Panmunjom.^[262] A major problematic negotiation point was prisoner of war (POW) repatriation.^[263] The PVA, KPA and UN Command could not agree on a system of repatriation because many PVA and KPA soldiers refused to be repatriated back to the north,^[264] which was unacceptable to the Chinese and North Koreans.^[265] A Neutral Nations Repatriation Commission, under the chairman Indian General K. S. Thimayya, was subsequently set up to handle the matter.^[266]

On 29 November 1952 U.S. President-Elect Dwight D. Eisenhower went to Korea to learn what might end the Korean War.^[267] Eisenhower took office on 20 January 1953. Stalin died a few weeks later on 5 March. The new Soviet leaders, engaged in their internal power struggle, had no desire to continue supporting China's efforts in Korea and issued a statement calling for an end to the hostilities.^[268] China could not continue the war without Soviet aid, and North Korea was no longer a major player. Armistice talks entered a new phase. With the United Nations' acceptance of India's proposed Korean War armistice,^[269] the KPA, the PVA and the UN Command signed the armistice agreement on 27 July 1953. South Korean president Syngman Rhee refused to sign the agreement. The war is considered to have ended at this point, even though there was no peace treaty.^[270] North Korea nevertheless claims that it won the Korean War.^[271][272]

Under the agreement, the belligerents established the Korean Demilitarized Zone (DMZ) along the front line, which vaguely follows the 38th parallel. In the eastern part, the DMZ runs north of the 38th parallel; to the west, it travels south of it. Kaesong, site of the initial armistice negotiations, was originally in pre-war South Korea but now is part of North Korea. The DMZ has since been patrolled by the KPA and the ROK, with the U.S. still operating as the UN Command.

After the war, Operation Glory was conducted from July to November 1954, to allow combatant countries to exchange their dead. The remains of 4,167 U.S. Army and U.S. Marine Corps dead were exchanged for 13,528 KPA and PVA dead, and 546 civilians dead in UN prisoner-of-war camps were delivered to the South Korean government.^[273] After Operation Glory, 416 Korean War unknown soldiers were buried in the National Memorial Cemetery of the Pacific (The Punchbowl), on the island of Oahu, Hawaii. Defense Prisoner of War/Missing Personnel Office (DPMO) records indicate that the PRC and North Korea transmitted 1,394 names, of which 858 were correct. From 4,167 containers of returned remains, forensic examination identified 4,219 individuals. Of these, 2,944 were identified as from the U.S., and all but 416 were identified by name.^[274] From 1996 to 2006, North Korea recovered 220 remains near the Sino-Korean border.^[275]

Continued division (1954–present)

Delegates sign the Korean Armistice Agreement in P'anmunjŏm.

The Korean Armistice Agreement provided for monitoring by an international commission. Since 1953, the Neutral Nations Supervisory Commission, composed of members from the Swiss^[276] and Swedish^[277] armed forces, has been stationed near the DMZ.

In April 1975, South Vietnam's capital of Saigon was captured by the People's Army of Vietnam. Encouraged by the success of the communist revolution in Indochina, Kim Il Sung saw it as an opportunity to invade South Korea. Kim visited China in April 1975 and met with Mao and Zhou to ask for military aid. Despite Pyongyang's expectations, however, Beijing refused to help North Korea for another war in Korea.^[278]

A U.S. Army officer confers with South Korean soldiers at Observation Post (OP) Ouellette, viewing northward, in April 2008

The DMZ as seen from the north, 2005

Since the armistice, there have been numerous incursions and acts of aggression by North Korea. From 1966 to 1969, a large number of cross-border incursions took place in what has been referred to as the Korean DMZ Conflict or the Second Korean War. In 1968, a North Korean commando team unsuccessfully attempted to assassinate South Korean president Park Chung Hee in the Blue House Raid. In 1976, the axe murder incident was widely publicized. Since 1974, four incursion tunnels leading to Seoul have been uncovered. In 2010, a North Korean submarine torpedoed and sank the South Korean corvette ROKS Cheonan, resulting in the deaths of 46 sailors.^[279] Again in 2010, North Korea fired artillery shells on Yeonpyeong island, killing two military personnel and two civilians.^[280]

After a new wave of UN sanctions, on 11 March 2013, North Korea claimed that the armistice had become invalid.^[281] On 13 March 2013, North Korea confirmed it ended the 1953 Armistice and declared North Korea "is not restrained by the North-South declaration on non-aggression".^[282] On 30 March 2013, North Korea stated that it entered a "state of war" with South Korea and declared that "The long-standing situation of the Korean peninsula being neither at peace nor at war is finally over".^[283] Speaking on 4 April 2013, U.S. Secretary of Defense Chuck Hagel informed the press that Pyongyang "formally informed" the Pentagon that it "ratified" the potential use of a nuclear weapon against South Korea, Japan and the United States of America, including Guam and Hawaii.^[284] Hagel also stated the U.S. would deploy the Terminal High Altitude Area Defense anti-ballistic missile system to Guam because of a credible and realistic nuclear threat from North Korea.^[285]

In 2016, it was revealed that North Korea approached the United States about conducting formal peace talks to end the war officially. While the White House agreed to secret peace talks, the plan was rejected because North Korea refused to discuss nuclear disarmament as part of the terms of the treaty.^[286]

On 27 April 2018, it was announced that North Korea and South Korea agreed to talks to end the ongoing 65-year conflict. They committed themselves to the complete denuclearization of the Korean Peninsula.^[287] North Korean leader Kim Jong Un and South Korean President Moon Jae-In signed the Panmunjom Declaration for Peace, Prosperity and Reunification of the Korean Peninsula.^[288] On 22 September 2021, Moon reiterated his call to end the Korean War formally, in his speech at the UN General Assembly.^[289]

Casualties

Approximately 3 million people died in the Korean War, the majority of whom were civilians, making it perhaps the deadliest conflict of the Cold War era.^{[34][35][290][291][292]} Samuel S. Kim lists the Korean War as the deadliest conflict in East Asia—the region most affected by armed conflict related to the Cold War.^[290] Although only rough estimates of civilian fatalities are available, scholars from Guenter Lewy to Bruce Cumings have noted that the percentage of civilian casualties in Korea was higher than in World War II or the Vietnam War, with Cumings putting civilian casualties at 2 million and Lewy estimating civilian deaths in the range of 2 million to 3 million.^[34][35]

Cumings states that civilians represent at least half of the war's casualties, while Lewy suggests that the civilian portion of the death toll may have gone as high as 70%, compared to Lewy's estimates of 42% in World War II and 30%–46% in the Vietnam War.^[34][35] Data compiled by the Peace Research Institute Oslo lists just under 1 million battle deaths over the course of the Korean War (with a range of 644,696 to 1.5 million) and a mid-value estimate of 3 million total deaths (with a range of 1.5 million to 4.5 million), attributing the difference to excess mortality among civilians from one-sided massacres, starvation, and disease.^[293] Compounding this devastation for Korean civilians, virtually all major cities on the Korean Peninsula were destroyed as a result of the war.^[35] In both per capita and absolute terms, North Korea was the country most devastated by the war. According to Charles K. Armstrong, the war resulted in the death of an estimated 12%–15% of the North Korean population (c. 10 million), "a figure close to or surpassing the proportion of Soviet citizens killed in World War II".^[123]

Military

Korean War memorials are found in every UN Command Korean War participant country; this one is in Pretoria, South Africa.

See also: Australia, Belgium, Canada, Colombia, Ethiopia, France, Greece, Luxembourg, Netherlands, New Zealand, Philippines, Thailand, Turkey, South Africa, United Kingdom, and United States

See also: China, North Korea, and Soviet Union

South Korea reported some 137,899 military deaths and 24,495 missing, 450,742 wounded, 8,343 POW.^[22]

According to the data from the US Department of Defense, the US suffered 33,686 battle deaths, 7,586 missing,^[294] along with 2,830 non-battle deaths. There were 17,730 other non-battle US military deaths that occurred outside Korea during the same period that were erroneously included as Korean War deaths until 2000.^[295][296] In addition, the U.S. suffered 103,284 wounded in action.^[297] The United Nations losses, excluding those of the United States or South Korea, amounted to 4,141 dead and 12,044 wounded in action.

American combat casualties were over 90% of non-Korean UN losses. US battle deaths were 8,516 up to their first engagement with the Chinese on 1 November 1950.^[298] The first four months prior to the Chinese intervention (which started near the end of October) were by far the bloodiest per day for the US forces as they engaged and destroyed the comparatively well-equipped KPA in intense fighting. American medical records show that from July to October 1950, the US Army sustained 31% of the combat deaths it ultimately incurred in the entire 37-month war.^[299] The US spent US$30 billion on the war.^[300] Some 1,789,000 American soldiers served in the Korean War, accounting for 31% of the 5,720,000 Americans who served on active duty worldwide from June 1950 to July 1953.^[27]

Deaths from the other non-American UN militaries totaled 3,730, with another 379 missing.^[22]

Details

•  United Kingdom:
  1,109 dead^[301]
  2,674 wounded^[301]
  179 MIA^[22]
  977 POW^[22]
•  Turkey:^[22]
  741 dead
  2,068 wounded
  163 MIA
  244 POW
•  Canada:
  516 dead^[302]
  1,042 wounded^[303]
  1 MIA^[22]
  33 POW^[304]
•  Australia:^[305]
  339 dead
  1,216 wounded
  43 MIA
  26 POW
•  France:^[22]
  262 dead
  1,008 wounded
  7 MIA
  12 POW
•  Greece^[22]
  192 dead
  543 wounded
  3 POW
•  Colombia:^[22]
  163 dead
  448 wounded
  28 POW
•  Thailand:^[22]
  129 dead
  1,139 wounded
  5 MIA
•  Ethiopia^[22]
  121 dead
  536 wounded
•  Netherlands:^[22]
  122 dead
  645 wounded
  3 MIA
•  Belgium:^[22]
  101 dead
  478 wounded
  5 MIA
  1 POW
•  Philippines:^[306]
  92 dead
  299 wounded
  97 MIA/POW
•  Japan:^[8]
  79 dead
•  South Africa:^[22]
  34 dead
  9 POW
•  New Zealand:^[306]
  34 dead
  299 wounded
  1 MIA/POW
•  Norway:^[22]
  3 dead
•  Luxembourg:^[22]
  2 dead
  13 wounded
•  India:^[307]
  1 dead

Data from official Chinese sources reported that the PVA had suffered 114,000 battle deaths, 21,000 deaths from wounds, 13,000 deaths from illness, 340,000 wounded, and 7,600 missing. 7,110 Chinese POWs were repatriated to China.^[33] In 2010, the Chinese government revised their official tally of war losses to 183,108 dead (114,084 in combat, 70,000 deaths from wounds, illness and other causes) and 25,621 missing.^[308] Overall, 73% of Chinese infantry troops served in Korea (25 of 34 armies, or 79 of 109 infantry divisions, were rotated in). More than 52% of the Chinese air force, 55% of the tank units, 67% of the artillery divisions, and 100% of the railroad engineering divisions were sent to Korea as well.^[309] Chinese soldiers who served in Korea faced a greater chance of being killed than those who served in World War II or the Chinese Civil War.^[310] In terms of financial cost, China spent over 10 billion yuan on the war (roughly US$3.3 billion), not counting USSR aid that had been donated or forgiven.^[311] This included $1.3 billion in money owed to the Soviet Union by the end of it. This was a relatively large cost, as China had only 4% of the national income of the United States.^[33] Spending on the Korean War constituted 34–43% of China's annual government budget from 1950 to 1953, depending on the year.^[311] Despite its underdeveloped economy, Chinese military spending was the world's fourth largest globally for most of the war after that of the United States, the Soviet Union, and the United Kingdom; however, by 1953, with the winding down of the Korean War and the escalation of the First Indochina War (which reached its peak in 1953–1954), French spending also surpassed Chinese spending by about a third.^[312]

According to the South Korean Ministry of National Defense, North Korean military losses totaled 294,151 dead, 91,206 missing, and 229,849 wounded, giving North Korea the highest military deaths of any belligerent in both absolute and relative terms.^[313] The PRIO Battle Deaths Dataset gave a similar figure for North Korean military deaths of 316,579.^[314] Chinese sources reported similar figures for the North Korean military of 290,000 "casualties" and 90,000 captured.^[33] The financial cost of the war for North Korea is unknown but was known to be massive in terms of both direct losses and lost economic activity; the country was devastated both by the cost of the war itself and the American strategic bombing campaign, which, among other things, destroyed 85% of North Korea's buildings and 95% of its power generation capacity.^[315] The Soviet Union suffered 299 dead, with 335 planes lost.^[316]

The Chinese and North Koreans estimated that about 390,000 soldiers from the United States, 660,000 soldiers from South Korea and 29,000 other UN soldiers were "eliminated" from the battlefield.^[33] Western sources estimate the PVA suffered about 400,000 killed and 486,000 wounded, while the KPA suffered 215,000 killed, 303,000 wounded, and over 101,000 captured or missing.^[317] Cumings cites a much higher figure of 900,000 fatalities among Chinese soldiers.^[34]

U.S. unpreparedness

In a postwar analysis of the unpreparedness of U.S. Army forces deployed to Korea during the summer and fall of 1950, Army Major General Floyd L. Parks stated "Many who never lived to tell the tale had to fight the full range of ground warfare from offensive to delaying action, unit by unit, man by man ... [T]hat we were able to snatch victory from the jaws of defeat ... does not relieve us from the blame of having placed our own flesh and blood in such a predicament."^[318]

A soldier of the Dutch detachment of the UN forces in North Korea prepares to return sniper fire, 1952

By 1950, U.S. Secretary of Defense Louis A. Johnson had established a policy of faithfully following President Truman's defense economization plans and had aggressively attempted to implement it even in the face of steadily increasing external threats. He consequently received much of the blame for the initial setbacks in Korea and the widespread reports of ill-equipped and inadequately trained U.S. military forces in the war's early stages.^[319]

As an initial response to the invasion, Truman called for a naval blockade of North Korea and was shocked to learn that such a blockade could be imposed only "on paper" since the U.S. Navy no longer had the warships with which to carry out his request.^[319][320] Army officials, desperate for weaponry, recovered Sherman tanks and other equipment from Pacific War battlefields and reconditioned them for shipment to Korea.^[319] Army ordnance officials at Fort Knox pulled down M26 Pershing tanks from display pedestals around Fort Knox in order to equip the third company of the Army's hastily formed 70th Tank Battalion.^[321] Without adequate numbers of tactical fighter-bomber aircraft, the Air Force took F-51 (P-51) propeller-driven aircraft out of storage or from existing Air National Guard squadrons and rushed them into front-line service. A shortage of spare parts and qualified maintenance personnel resulted in improvised repairs and overhauls. A Navy helicopter pilot aboard an active duty warship recalled fixing damaged rotor blades with masking tape in the absence of spares.^[322]

U.S. Army Reserve and Army National Guard infantry soldiers and new inductees (called to duty to fill out understrength infantry divisions) found themselves short of nearly everything needed to repel the North Korean forces: artillery, ammunition, heavy tanks, ground-support aircraft, even effective anti-tank weapons such as the M20 3.5-inch (89 mm) "Super Bazooka".^[323] Some Army combat units sent to Korea were supplied with worn-out, "red-lined" M1 rifles or carbines in immediate need of ordnance depot overhaul or repair.^[324][325] Only the Marine Corps, whose commanders had stored and maintained their World War II surplus inventories of equipment and weapons, proved ready for deployment, though they still were woefully understrength,^[326] as well as in need of suitable landing craft to practice amphibious operations (Secretary of Defense Louis Johnson had transferred most of the remaining craft to the Navy and reserved them for use in training Army units).^[327]

Armored warfare

The initial assault by KPA forces was aided by the use of Soviet T-34-85 tanks.^[328] A KPA tank corps equipped with about 120 T-34s spearheaded the invasion. These faced an ROK that had few anti-tank weapons adequate to deal with the T-34s.^[329] Additional Soviet armor was added as the offensive progressed.^[330] The KPA tanks had a good deal of early successes against ROK infantry, Task Force Smith, and the U.S. M24 Chaffee light tanks that they encountered.^[331][332] Interdiction by ground attack aircraft was the only means of slowing the advancing KPA armor. The tide turned in favor of the UN forces in August 1950 when the KPA suffered major tank losses during a series of battles in which the UN forces brought heavier equipment to bear, including M4A3 Sherman and M26 medium tanks, as well as the British Centurion, Churchill and Cromwell tanks.^[333]

The Incheon landings on 15 September cut off the KPA supply lines, causing their armored forces and infantry to run out of fuel, ammunition, and other supplies. As a result of this and the Pusan perimeter breakout, the KPA had to retreat, and many of the T-34s and heavy weapons had to be abandoned. By the time the KPA withdrew from the South, 239 T-34s and 74 SU-76 self-propelled guns were lost.^[334] After November 1950, KPA armor was rarely encountered.^[335]

Following the initial assault by the North, the Korean War saw limited use of tanks and featured no large-scale tank battles. The mountainous, forested terrain, especially in the eastern central zone, was poor tank country, limiting their mobility. Through the last two years of the war in Korea, UN tanks served largely as infantry support and mobile artillery pieces.^[336]

Naval warfare

To disrupt North Korean communications, USS Missouri fires a salvo from its 16-inch guns at shore targets near Chongjin, North Korea, 21 October 1950

Because neither Korea had a significant navy, the war featured few naval battles. A skirmish between North Korea and the UN Command occurred on 2 July 1950; the U.S. Navy cruiser USS Juneau, the Royal Navy cruiser HMS Jamaica and the Royal Navy frigate HMS Black Swan fought four North Korean torpedo boats and two mortar gunboats, and sank them. USS Juneau later sank several ammunition ships that had been present. The last sea battle of the Korean War occurred days before the Battle of Incheon; the ROK ship PC-703 sank a North Korean minelayer in the Battle of Haeju Island, near Incheon. Three other supply ships were sunk by PC-703 two days later in the Yellow Sea.^[337]

During most of the war, the UN navies patrolled the west and east coasts of North Korea, sinking supply and ammunition ships and denying the North Koreans the ability to resupply from the sea. Aside from very occasional gunfire from North Korean shore batteries, the main threat to UN navy ships was from magnetic mines. During the war, five U.S. Navy ships were lost to mines: two minesweepers, two minesweeper escorts, and one ocean tug. Mines and gunfire from North Korean coastal artillery damaged another 87 U.S. warships, resulting in slight to moderate damage.^[338]

Aerial warfare

The war was the first in which jet aircraft played the central role in air combat. Once-formidable fighters such as the P-51 Mustang, F4U Corsair, and Hawker Sea Fury^[339]—all piston-engined, propeller-driven, and designed during World War II—relinquished their air-superiority roles to a new generation of faster, jet-powered fighters arriving in the theater. For the initial months of the war, the P-80 Shooting Star, F9F Panther, Gloster Meteor, and other jets under the UN flag dominated the Korean People's Air Force (KPAF) propeller-driven Soviet Yakovlev Yak-9 and Lavochkin La-9s.^[340][341] By early August 1950, the KPAF was reduced to only about 20 planes.^[342]

A USAF Lockheed P-80 Shooting Star dropping napalm in Korea, May 1952

The Chinese intervention in late October 1950 bolstered the KPAF with the MiG-15, one of the world's most advanced jet fighters.^[340] The USAF countered the MiG-15 by sending over three squadrons of its most capable fighter, the F-86 Sabre. These arrived in December 1950.^[343][344] The Soviet Union denied the involvement of their personnel in anything other than an advisory role, but air combat quickly resulted in Soviet pilots dropping their code signals and speaking over the radio in Russian. This known direct Soviet participation was a casus belli that the UN Command deliberately overlooked, lest the war expand to include the Soviet Union and potentially escalate into atomic warfare.^[340]

After the war and to the present day, the USAF reported an inflated F-86 Sabre kill ratio in excess of 10:1, with 792 MiG-15s and 108 other aircraft shot down by Sabres, and 78 Sabres lost to enemy fire.^[345][346] The Soviet Air Force reported some 1,100 air-to-air victories and 335 MiG combat losses, while China's PLAAF reported 231 combat losses, mostly MiG-15s, and 168 other aircraft lost. The KPAF reported no data, but the UN Command estimates some 200 KPAF aircraft lost in the war's first stage, and 70 additional aircraft after the Chinese intervention. The USAF disputes Soviet and Chinese claims of 650 and 211 downed F-86s, respectively.^[347][348]

More modern estimates place the overall USAF kill ratio at around 1.8:1 with the ratio dropping to 1.3:1 against MiG-15s with Soviet pilots but increasing to a dominant 12:1 against Chinese and North Korean adversaries.^{[349][350][351]}

Reports by Lieutenant General Sidor Slyusarev, commander of Soviet air forces in Korea, are more favorable to the communist side. The 64th Corps claimed a total 1,097 enemy aircraft of all types during operations, for the loss of 335 aircraft (including lost to enemy ground fire, accidents, etc) and 110 pilots. Soviet reports put the overall kill ratio at 3.4:1 in favor of Soviet pilots.^[352] As reported, effectiveness of the Soviet fighters declined as the war progressed. from an overall kill ratio of 7.9:1 from November 1950 through January 1952, declining to 2.2:1 in later 1952 and 1.9:1 in 1953. This was because more advanced jet fighters appeared on the UN side as well as improved U.S. tactics.^[352]

Regardless of the actual ratio, American Sabres were very effective at controlling the skies over Korea. Since no other UN fighter could contend with the MiG-15, F-86s largely took over air combat once they arrived, relegating other aircraft to air-to-ground operations. Despite much greater numbers (the number of Sabres in theater never exceeded 150 while MiG-15s reached 900 at their peak), communist aircraft were seldom encountered south of Pyongyang. UN ground forces, supply lines, and infrastructure were not attacked from the air. Although North Korea had 75 airfields capable of supporting MiGs, after 1951, any serious effort to operate from them was abandoned. The MiGs were instead based across the Yalu River in the safety of China. This confined most air-to-air engagements to MiG Alley. UN aircraft had free rein to conduct strike missions over enemy territory with little fear of interception. Although jet dogfights are remembered as a prominent part of the Korean War, counter-air missions comprised just 12% of Far East Air Forces sorties, and four times as many sorties were performed for close air support and interdiction.^[342]

The war marked a major milestone not only for fixed-wing aircraft, but also for rotorcraft, featuring the first large-scale deployment of helicopters for medical evacuation (medevac).^[353] In 1944–45, during World War II, the YR-4 helicopter had seen limited ambulance duty. In Korea, where rough terrain prevented use of the jeep as a speedy medevac vehicle,^[354] helicopters like the Sikorsky H-19 were heavily used. This helped reduce fatal casualties to a dramatic degree when combined with complementary medical innovations such as Mobile Army Surgical Hospitals (MASH).^[355] As such, the medical evacuation and care system for the wounded was so effective for the UN forces that a wounded soldier who arrived at a MASH unit alive typically had a 97% chance of survival.^[356] The limitations of jet aircraft for close air support highlighted the helicopter's potential in the role, leading to the development of the helicopter gunships used in the Vietnam War.^[353]

U.S. threat of atomic warfare

Mark 4 bomb, seen on display, transferred to the 9th Bombardment Wing, Heavy

On 5 November 1950, the U.S. Joint Chiefs of Staff issued orders for the retaliatory atomic bombing of Manchurian PRC military bases, if either of their armies crossed into Korea or if PRC or KPA bombers attacked Korea from there. President Truman ordered the transfer of nine Mark 4 nuclear bombs "to the Air Force's Ninth Bomb Group, the designated carrier of the weapons ... [and] signed an order to use them against Chinese and Korean targets", which he never transmitted.^[357]

Many U.S. officials viewed the deployment of nuclear-capable (but not nuclear-armed) B-29 bombers to Britain as helping to resolve the Berlin Blockade of 1948–1949. Truman and Eisenhower both had military experience and viewed nuclear weapons as potentially usable components of their military. During Truman's first meeting to discuss the war on 25 June 1950, he ordered plans be prepared for attacking Soviet forces if they entered the war. By July, Truman approved another B-29 deployment to Britain, this time with bombs (but without their cores), to remind the Soviets of U.S. offensive ability. Deployment of a similar fleet to Guam was leaked to The New York Times. As UN forces retreated to Pusan, and the CIA reported that mainland China was building up forces for a possible invasion of Taiwan, the Pentagon believed that Congress and the public would demand using nuclear weapons if the situation in Korea required them.^[358]

As PVA forces pushed back the UN forces from the Yalu River, Truman stated during a 30 November 1950 press conference that using nuclear weapons was "always [under] active consideration", with control under the local military commander.^[358] Indian ambassador K. Madhava Panikkar reports "that Truman announced he was thinking of using the atom bomb in Korea. But the Chinese seemed unmoved by this threat ... The PRC's propaganda against the U.S. was stepped up. The 'Aid Korea to resist America' campaign was made the slogan for increased production, greater national integration, and more rigid control over anti-national activities. One could not help feeling that Truman's threat came in useful to the leaders of the Revolution, to enable them to keep up the tempo of their activities."^{[188][359][360]}

After his statement caused concern in Europe, Truman met on 4 December with UK Prime Minister and Commonwealth spokesman Clement Attlee, French Premier René Pleven, and French Foreign Minister Robert Schuman to discuss their worries about atomic warfare and its likely continental expansion. The U.S.' forgoing atomic warfare was not because of "a disinclination by the Soviet Union and People's Republic of China to escalate [the Korean War]", but because UN allies—notably the UK, the Commonwealth, and France—were concerned about a geopolitical imbalance rendering NATO defenseless while the U.S. fought China, who then might persuade the Soviet Union to conquer Western Europe.^[188][361] The Joint Chiefs of Staff advised Truman to tell Attlee that the U.S. would use nuclear weapons only if necessary to protect an evacuation of UN troops, or to prevent a "major military disaster".^[358]

On 6 December after the Chinese intervention repelled the UN armies from northern North Korea, General J. Lawton Collins (Army Chief of Staff), General MacArthur, Admiral C. Turner Joy, General Stratemeyer and staff officers Major General Doyle Hickey, Major General Charles A. Willoughby and Major General Edwin K. Wright met in Tokyo to plan strategy countering the Chinese intervention; they considered three potential atomic warfare scenarios encompassing the next weeks and months of warfare.^[188]

• In the first scenario: If the PVA continued attacking in full and the UN Command was forbidden to blockade and bomb China, and without Taiwanese reinforcements, and without an increase in U.S. forces until April 1951 (four National Guard divisions were due to arrive), then atomic bombs might be used in North Korea.^[188]
• In the second scenario: If the PVA continued full attacks and the UN Command blockaded China and had effective aerial reconnaissance and bombing of the Chinese interior, and the Taiwanese soldiers were maximally exploited, and tactical atomic bombing was to hand, then the UN forces could hold positions deep in North Korea.^[188]
• In the third scenario: if China agreed not to cross the 38th parallel border, MacArthur would recommend UN acceptance of an armistice disallowing PVA and KPA troops south of the parallel, and requiring PVA and KPA guerrillas to withdraw northwards. The Eighth Army would remain to protect the Seoul–Incheon area, while X Corps would retreat to Pusan. A UN commission should supervise implementation of the armistice.^[188]

Both the Pentagon and the State Department were cautious about using nuclear weapons because of the risk of general war with China and the diplomatic ramifications. Truman and his senior advisors agreed and never seriously considered using them in early December 1950 despite the poor military situation in Korea.^[358]

In 1951, the U.S. escalated closest to atomic warfare in Korea. Because China deployed new armies to the Sino-Korean frontier, ground crews at the Kadena Air Base, Okinawa, assembled atomic bombs for Korean warfare, "lacking only the essential pit nuclear cores." In October 1951, the United States effected Operation Hudson Harbor to establish a nuclear weapons capability. USAF B-29 bombers practiced individual bombing runs from Okinawa to North Korea (using dummy nuclear or conventional bombs), coordinated from Yokota Air Base in east-central Japan. Hudson Harbor tested "actual functioning of all activities which would be involved in an atomic strike, including weapons assembly and testing, leading, [and] ground control of bomb aiming". The bombing run data indicated that atomic bombs would be tactically ineffective against massed infantry, because the "timely identification of large masses of enemy troops was extremely rare".^{[362][363][364][365][366]}

Ridgway was authorized to use nuclear weapons if a major air attack originated from outside Korea. An envoy was sent to Hong Kong to deliver a warning to China. The message likely caused Chinese leaders to be more cautious about potential U.S. use of nuclear weapons, but whether they learned about the B-29 deployment is unclear, and the failure of the two major Chinese offensives that month likely was what caused them to shift to a defensive strategy in Korea. The B-29s returned to the United States in June.^[358]

Despite the greater destructive power that atomic weapons would bring to the war, their effects on determining the war's outcome would have likely been minimal. Tactically, given the dispersed nature of PVA/KPA forces, the relatively primitive infrastructure for staging and logistics centers, and the small number of bombs available (most would have been conserved for use against the Soviets), atomic attacks would have limited effects against the ability of China to mobilize and move forces. Strategically, attacking Chinese cities to destroy civilian industry and infrastructure would cause the immediate dispersion of the leadership away from such areas and give propaganda value for the communists to galvanize the support of Chinese civilians. Since the Soviets were not expected to intervene with their few primitive atomic weapons on China or North Korea's behalf, the threat of a possible nuclear exchange was unimportant in the decision not to deploy atomic bombs; their use offered little operational advantage and would undesirably lower the "threshold" for using atomic weapons against non-nuclear states in future conflicts.^[367]

When Eisenhower succeeded Truman in early 1953, he was similarly cautious about using nuclear weapons in Korea. The administration prepared contingency plans to use them against China, but like Truman, he feared that doing so would result in Soviet attacks on Japan. The war ended as it began, without U.S. nuclear weapons deployed near battle.^[358]

North Korea

As a result of the war, "North Korea had been virtually destroyed as an industrial society". After the armistice, Kim Il Sung requested Soviet economic and industrial assistance. In September 1953, the Soviet government agreed to "cancel or postpone repayment for all ... outstanding debts", and promised to grant North Korea one billion rubles in monetary aid, industrial equipment and consumer goods. Eastern European members of the Soviet Bloc also contributed with "logistical support, technical aid, [and] medical supplies". China canceled North Korea's war debts, provided 800 million yuan, promised trade cooperation and sent in thousands of troops to rebuild damaged infrastructure.^[376] Contemporary North Korea remains underdeveloped^[379] and continues to be a totalitarian dictatorship since the end of the war, with an elaborate cult of personality around the Kim dynasty.^{[380][381][382]}

The means of production are owned by the state through state-run enterprises and collectivized farms. Most services—such as healthcare, education, housing and food production—are subsidized or state-funded. Estimates based on the most recent North Korean census suggest that 240,000 to 420,000 people died as a result of the 1990s North Korean famine and that there were 600,000 to 850,000 unnatural deaths in North Korea from 1993 to 2008.^[383] A study by South Korean anthropologists of North Korean children who had defected to China found that 18-year-old males were 13 cm (5 in) shorter than South Koreans their age because of malnutrition.^[384]

The Korean Peninsula at night, shown in a 2017 composite photograph from NASA

Present-day North Korea follows Songun, or "military-first" policy and has the highest number of military and paramilitary personnel in the world, with 7,769,000 active, reserve and paramilitary personnel, or approximately 30% of its population. Its active-duty army of 1.28 million is the fourth largest in the world, after China, the United States and India; consisting of 4.9% of its population. North Korea possesses nuclear weapons. A 2014 UN inquiry into abuses of human rights in North Korea concluded that, "the gravity, scale and nature of these violations reveal a state that does not have any parallel in the contemporary world," with Amnesty International and Human Rights Watch holding similar views.^{[385][386][387][388]}

South Korea

Postwar recovery was different in the two Koreas. South Korea, which started from a far lower industrial base than North Korea (the latter contained 80% of Korea's heavy industry in 1945),^[48] stagnated in the first postwar decade. In 1953, South Korea and the United States signed a Mutual Defense Treaty.

South Korean anti-Americanism after the war was fueled by the presence and behavior of United States Forces Korea military personnel and U.S. support for Park's authoritarian regime, a fact still evident during the country's democratic transition in the 1980s.^[389] However, anti-Americanism has declined significantly in South Korea in recent years, from 46% favorable in 2003 to 74% favorable in 2011,^[390] making South Korea one of the most pro-U.S. countries in the world.^[391]

A large number of mixed-race "GI babies" (offspring of U.S. and other UN soldiers and Korean women) were filling up the country's orphanages. Because Korean traditional society places significant weight on paternal family ties, bloodlines, and purity of race, children of mixed race or those without fathers are not easily accepted in South Korean society. International adoption of Korean children began in 1954.^[392] The U.S. Immigration Act of 1952 legalized the naturalization of non-Blacks and non-Whites as U.S. citizens and made possible the entry of military spouses and children from South Korea. With the passage of the Immigration Act of 1965, which substantially changed U.S. immigration policy toward non-Europeans, Koreans became one of the fastest-growing Asian groups in the United States.^[393]

Communism

Mao Zedong's decision to take on the United States was a direct attempt to confront what the communist bloc viewed as the strongest anti-communist power in the world, undertaken at a time when the Chinese communist regime was still consolidating its own power after winning the Chinese Civil War. Mao supported intervention not to save North Korea, but because he believed that a military conflict with the U.S. was inevitable after the U.S. entered the war, and to appease the Soviet Union to secure military dispensation and achieve Mao's goal of making China a major world military power. Mao was equally ambitious in improving his own prestige inside the communist international community by demonstrating that his Marxist concerns were international. In his later years, Mao believed that Stalin only gained a positive opinion of him after China's entrance into the Korean War. Inside mainland China, the war improved the long-term prestige of Mao, Zhou, and Peng, allowing the Chinese Communist Party to increase its legitimacy while weakening anti-communist dissent.^[394]

North Koreans touring the Museum of American War Atrocities in 2009

The Chinese government has encouraged the viewpoint that the war was initiated by the United States and South Korea, though ComIntern documents have shown that Mao sought approval from Stalin to enter the war. In Chinese media, the Chinese war effort is considered as an example of China's engaging the strongest power in the world with an underequipped army, forcing it to retreat, and fighting it to a military stalemate. These successes were contrasted with China's historical humiliations by Japan and by Western powers over the previous hundred years, highlighting the abilities of the PLA and the Chinese Communist Party. The most significant negative long-term consequence of the war for China was that it led the United States to guarantee the safety of Chiang Kaishek's regime in Taiwan, effectively ensuring that Taiwan would remain outside of PRC control through the present day.^[394] Mao had also discovered the usefulness of large-scale mass movements in the war while implementing them among most of his ruling measures over PRC.^[395] Anti-U.S. sentiments, which were already a significant factor during the Chinese Civil War, were ingrained into Chinese culture during the communist propaganda campaigns of the Korean War.^[396]

The Korean War affected other participant combatants. Turkey, for example, entered NATO in 1952,^[397] and the foundation was laid for bilateral diplomatic and trade relations with South Korea.^[398] The war also played role in the refugee crisis in Turkey in 1950-1951.

War memorials

• Korean War Memorial Wall,^map Brampton, Ontario
• Korean War Veterans Memorial, Washington, D.C.
• Memorial of the War to Resist U.S. Aggression and Aid Korea, Dandong, Liaoning, China
• National War Memorial (New Zealand)
• Philadelphia Korean War Memorial
• United Nations Memorial Cemetery, Busan, Republic of Korea
• Memorial of Turks Who Fought in Korea, Ankara, Turkey
• Victorious War Museum, Pyongyang, North Korea
• War Memorial of Korea Yongsan-dong, Yongsan-gu, Seoul, South Korea

Citations

Bibliography

Historical

• THE KOREAN WAR (1) - ROK Ministry of National Defense Institute for Military History, 1997 (E-BOOK) Archived 9 July 2023 at the Wayback Machine
• THE KOREAN WAR (1) - ROK Ministry of National Defense Institute for Military History, 1997 (PDF) Archived 7 June 2023 at the Wayback Machine
• THE KOREAN WAR (2) - ROK Ministry of National Defense Institute for Military History, 1998 (E-BOOK) Archived 9 July 2023 at the Wayback Machine
• THE KOREAN WAR (2) - ROK Ministry of National Defense Institute for Military History, 1999 (PDF) Archived 7 June 2023 at the Wayback Machine
• THE KOREAN WAR (3) - ROK Ministry of National Defense Institute for Military History, 1999 (E-BOOK) Archived 9 July 2023 at the Wayback Machine
• THE KOREAN WAR (3) - ROK Ministry of National Defense Institute for Military History, 1998 (PDF) Archived 7 June 2023 at the Wayback Machine
• History of the Just Fatherland Liberation War of the Korean People (PDF) The Research Institute of History, Academy of Sciences of the Democratic People's Republic of Korea
• Anniversary of the Korean War Armistice: Truman on Acheson's Crucial Role in Going to War Archived 21 February 2015 at the Wayback Machine Shapell Manuscript Foundation
• Korean War resources, Dwight D. Eisenhower Presidential Library Archived 26 June 2014 at the Wayback Machine
• North Korea International Documentation Project
• Grand Valley State University Veteran's History Project digital collection
• The Forgotten War, Remembered – four testimonials in The New York Times
• Collection of Books and Research Materials on the Korean War Archived 27 April 2021 at the Wayback Machine an online collection of the United States Army Center of Military History
• Korean War, US Army Signal Corps Photograph Collection U.S. Army Heritage and Education Center, Carlisle, Pennsylvania
• The Korean War at History.com
• Koreanwar-educator.org
• The short film Film No. 927 is available for free viewing and download at the Internet Archive.

Media

• West Point Atlas of the Korean War Archived 16 March 2021 at the Wayback Machine
• The Korean War You Never Knew – slideshows by Life magazine
• U.S. Army Korea Media Center official Korean War online image archive
• Rare pictures of the Korean War from the U.S. Library of Congress and National Archives
• Land of the Morning Calm Canadians in Korea – multimedia project including veteran interviews
• Pathé Archived 6 January 2012 at the Wayback Machine Online newsreel archive featuring films on the war
• CBC Digital Archives – Forgotten Heroes: Canada and the Korean War
• Uncertain Enemies: Soviet Pilots in the Korean War. Air Power History. (Spring 1997). 44, 1, 32–45.

Organizations

• Korea Defense Veterans of America
• Korean War Ex-POW Association
• Korean War Veterans Association
• The Center for the Study of the Korean War

Memorials

• Korean Children's War Memorial
• Chinese 50th Anniversary Korean War Memorial