Korean War
  • June, 1950
  • July, 1950
  • August, 1950
  • September, 1950
  • October, 1950
  • November, 1950
  • December, 1950
  • January, 1951
  • February, 1951
  • March, 1951
  • April, 1951
  • May, 1951
  • June, 1951
  • July, 1951

25 June 1950- 25 June 1951


Korean Peninsula


South Korea liberated all of North Korea, re-establishment of Korean Republic

  • South Korea 600,000
  • United States 210,000
  • United Kingdom 15,000
  • Canada 8000
  • others 9750
  • Total: 842,750
  • Flag of the People's Republic of China 670,000
  • North Korea 275,000
  • Soviet Union 5000
  • Total: 950,000
Casualties and Losses

Total Dead: 80,450
Total Wounded: 150,000

Total Dead: 260,730
Total Wounded: 560,000


The Korean War was a major engagement between North Korea and South Korea, and the first hot war of the Cold War. It began as a result of World War II, which resulted in the defeat of the Empire of Japan, the liberation of the Korean Peninsula, and the division of Korea between a democratic South Korea and a Communist North Korea.


The Korean Peninsula had existed in a state of East Asian peace since the 1300s, under the Joseon Dynasty which ruled the unified peninsula. Then, it became a Japanese puppet following the 1st Sino-Japanese War, and later was annexed as part of Japan during the immediate build-up to World War II. After Japan's defeat, it was divided between American and Soviet spheres, which would eventually come into conflict in the Korean War.

Korean History

In 918, a powerful dynasty, the Goryeo Dynasty, grew to power in Korea. Under this dynasty, Korea was unified, and it was under a relatively peaceful time, until its fall in 1392. Internal fighting and other factors led to the dynasty's downfall, but an equally powerful successor state came about - the Joseon Dynasty.

This dynasty, which was the longest ruling Confucian dynasty in history, peacefully ruled the Korean Peninsula from 1392 to 1897. Japan then controlled the Korean Empire, from 1897-1910 until they outright annexed Korea.

World War II

Korean nationalists fought against Japan during World War II. Many Koreans fought notably in Burma, and Communist Koreans (under Kim Il-Sung) fought in Korea and Manchuria.

Japan also forced 2.3 million Koreans into wartime production labor, and provided 32% of Japan's labor. Troops were conscripted and rationing was severe. In Hiroshima and Nagasaki, 25% of people killed were Korean.

Division of Korea

During the Cairo Conference of 1943, allied leaders agreed that Korea should be free, unified and independent. This was agreed upon by the US, UK and Republic of China.

However, in 1945 the Soviets were granted spheres of influence which included satellite puppets to serve as buffer states. While Korea was not specifically mentioned, China and Manchuria were, as part of the Soviet sphere.

Later in 1945, the Potsdam Conference unilaterally divided Korea at the 38th Parallel, between Soviet and American spheres of influence. The USSR was out of Korea by 1948, and the US was out by 1949.

Warfare Pre-Atomic Bomb

Kim, Mao, and Stalin

Mao-Kim 1954

Kim Il-Sung and Mao Zedong (from left)

Kim Il-Sung of North Korea worked extensively to gain the approval of both Joseph Stalin of the USSR, and Mao Zedong of the People's Republic of China, before he launched the invasion. At this time, Soviets drew up plans for the invasion on behalf of Kim, and eventually decided to give Kim approval, so long as Mao and the PRC sent their military to aid the North Koreans, to avoid a war between the US and USSR.

Following the end of the First Chinese Civil War, Korean troops who had fought under China were sent back to North Korea so they could be integrated into the North Korean armed forces. In addition, many tanks, aircraft and other weapons were sent to Kim Il-sung's armies.

Mao gave his approval to begin the invasion of South Korea. As Soviet generals drew up war plans, Kim Il-Sung sent diplomats to South Korea to negotiate more favorable terms for North Korea - an offer he knew South Korea would reject. On 6-2-5, June 25, 1950, the North Korean Army crossed the 38th Parallel.

North Korean Mobilize

Korean People's Army (North Koreans) Advances

Communist Surge

The first fighting began at dawn on June 25th, 1950. It is generally agreed upon that North Korea attacked first along the Ongjin Peninsula, but the South Koreans took Haeju early on in the fighting. Within an hour, North Korean heavy artillery and armored vehicles crossed the border throughout all of the 38th Parallel.

The South Koreans were extremely under-prepared, and lacked adequate anti-tank defences. By June 27th, Syngman Rhee and his top-level government officials fled Seoul in secret. Even with the bombing of a bridge over the Han River, Seoul fell on June 28th. By the end of June, only 23% of all South Korean troops could be accounted for.

US Engagement

President Truman of the United States debated whether or not to get involved in this "civil war." He was unsure of the overall implications, of all forms of involvement. He was mostly afraid that Korea would be used by the Soviets as a diversion for US forces while the Soviets could strike a more valuable nation - or the US itself.

In addition, Korea was not part of Truman's plan for the Cold War. It laid outside of the Strategic Defense Perimeter. However, Korea's proximity to Japan, an American protectorate, caused Truman to act. He proposed an invasion of Korea to the UN. The UN approved the invasion, and by July, US/UN troops were in Korea.

July 6th, 1950 marked the first US battle in Korea. US forces attempted to delay Communist forces at Osan, but failed under North Korean tanks. Later, in the Battle of Taejon, American forces were again repelled from the city by North Korean forces.


In August, Allied American, UN and South Korean troops had been pushed back into the area around Pusan. In September, the "Pusan Perimeter," a line defined by the Nakdong River, had been secured. It controlled about 10% of South Korea - the rest was under control of the Communist North.

The Battle of the Pusan Perimeter raged throughout August and September, and during this time, the US Air Force consistently bombarded enemy lines, roads and bridges. The North Koreans had to hide during day and only conduct operations at night.


General Douglas MacArthur, the UN Commander-in-Chief, planned a breakout from the perimeter at Pusan by using an amphibious assault and landing at Inchon, a city in South Korea that was occupied by the North.

Almost 50,000 men, mostly from Japan, were landed at Inchon in mid-September under heavy cover from the Allied artillery. The men landed with great success, and met light resistance from North Koreans who were occupied at Pusan.

At the same time, the troops stuck in Pusan began an assault on Communist forces, who were poorly instructed and led as to where to go. Kim Il-Sung didn't follow the advice of Mao's General Zhou Enlai, or Stalin's General Matvei Zakharov, and defended Pusan instead of falling back to defend Seoul. Seoul was recaptured by UN forces on September 25, 1950.

Crossing the 38th Parallel

38th Parallel Crossing

Supply Line Crossing the 38th Parallel

Following the recapture of Seoul, MacArthur pursued the idea to invade the North Korean homeland. At first, President Truman was opposed to the idea, but MacArthur was eventually granted permission by Truman's Secretary of Defence.

When the People's Republic of Korea refused unconditional surrender to the UN forces, MacArthur's forces crossed back over the 38th Parallel on October 1, 1950. On October 19, Pyongyang fell to South Korean and American forces. By the end of the month, 135,000 Communist Prisoners of War were held by the UN forces.

Chinese Engagement

The People's Republic of China had been mobilizing for an invasion of Taiwan and the Republic of China when news of the UN forces crossing the 38th Parallel reached Chairman Mao Zedong and Premier Zhou Enlai. Mao reorganized the forces that were preparing to invade Taiwan, and instead ordered them to the Sino-Korean border.

As soon as support from Stalin was secured, Communist Chinese troops crossed into North Korea of October 19. They began the "First Phase Offensive" on October 25, 1950. Backed by Soviet air-support, the Chinese won a few battles using the enormity of their army. On November 25, the Chinese counter-attacked the American "Home by Christmas Offensive" with their "Second Phase Offensive." By late December, fighting in Korea was around the 38th Parallel, directly as a result of the "Second Phase."

Chinese Take Seoul

Chinese Take Seoul

On December 31, 1950 the "Third Phase Offensive" began. This offensive used a tactic of night-time encirclement which gave the Chinese the element of surprise and numerically superior forces. On January 4, 1954, Seoul fell for a second time. At this time, MacArthur first considered using an atomic bomb.

On February 17, 1951, China implemented the "Fourth Phase Offensive." It was initially successful, but after a crushing defeat by a much smaller force at Hoengseong and the lack of adequate logistics, the offensive stopped.

The Chinese supply lines were too drawn out, following the first four offensives, so American, Korean and UN forces recaptured lost ground, including Seoul in March 14, 1951.

Atomic Bomb

Suggested Use

General MacArthur, who was widely popular amongst his men in Korea, felt that he was under the UN command, with US support. He was, in fact, declared as the Supreme Commander of the UN Forces. Therefore, MacArthur largely felt he had a good deal of autonomy from the US government.

MacArthur viewed the Korean War as a war on China and North Korea, whereas Truman viewed the war as only a war on North Korea. MacArthur had already wanted to invade China prior to the Chinese invasion of Korea in October of 1950.

As early as October 15, 1950, MacArthur had observed to Truman that the Chinese kept their military forces close together, and vulnerable to a tactical nuclear strike. Truman vehemently rejected the very notion, and MacArthur respected the decision until the Third Phase Offensive.

With China rapidly gaining land in Korea, MacArthur thought a well-placed atomic bomb would prevent the Chinese from carrying on in the war. MacArthur officially suggested use of a tactical atomic bombing on November 30, 1950.

Relieving MacArthur

President Harry Truman decided, on April 11, 1951, that Supreme Commander Douglas MacArthur, was to be relieved from command of the American, South Korean and UN Forces in Korea. The largest factors included MacArthur's idea of using an atomic bomb, which he considered at his command.

In fact, Truman had stated, "The military commander in the field will have charge of the use of the [atomic] weapons, as he always has." The real reason, as many historians and contemporaries believe, is that Truman felt he would lose in the polls if he was perceived as being commanded by MacArthur.

On April 11, 1951 a reluctant Omar Bradley wrote, on behalf of President Truman,

I deeply regret that it becomes my duty as President and Commander-in-Chief of the United States military forces to replace you as Supreme Commander, Allied Powers; Commander-in-Chief, United Nations Command; Commander-in-Chief, Far East; and Commanding General, U.S. Army, Far East.
You will turn over your commands, effective at once, to Lt. Gen. Matthew B. Ridgway. You are authorized to have issued such orders as are necessary to complete desired travel to such place as you select.
My reasons for your replacement will be made public concurrently with the delivery to you of the foregoing order, and are contained in the next following message, especially with regard to Truman's order to restrict military interaction with the media.

Reaction to MacArthur's Dismissal

The relief of command from Truman to MacArthur shocked the nation. Truman later called it the most difficult decision of his time in office - more difficult even than dropping two atomic bombs. Immediately, Republican Senator Robert Taft called for Truman's impeachment.

In Asia, MacArthur was met by Emperor Hirohito, the first time an Emperor of Japan had visited a foreigner without a title or rank. He returned to San Francisco to a throng of 500,000 people, who eagerly watched a parade in his honor.

On April 19, 1951, at the invitation of Congress, MacArthur gave a notable speech to a joint-session of Congress. In the speech, he declared boldly, "Once war is forced upon us, there is no other alternative than to apply every available means to bring it to a swift end. War's very object is victory, not prolonged indecision. In war there can be no substitute for victory."

MacArthur managed to seek an audience with Senators Kenneth McKellar (D-TN) and Robert Taft (R-OH) and Congressmen Sam Rayburn (D-TX) and Joseph William Martin, Jr. (R-MA). Between those four men, top-level leadership from both political parties and both Houses of Congress were represented. MacArthur convinced them of the need to use an atomic bomb on a Chinese military base outside of Korea.

Atomic Bombing

Atomic explosion 625

"Big Boy" explosion over Teng Sha Ho, April 24 1951

Under pressure from the public and Congress, Harry Truman decided that he should listen to MacArthur's advice and "apply every available mean to bring it to a swift end." Already stationed in Guam were 10 B-29 Superfortresses and all components to a nuclear missile except for the fissile core. On April 23, an atomic bomb was prepared and sent to Kadena AFB on Okinawa, Japan.

On the morning of April 24, 1951 Colonel Kenny Roberson took off in the B-29 Superfortress Praetorian. On board was the Mark 4 Atomic Bomb, "Big Boy." Roberson steered the plane the needed 949 miles from Kadena AFB to Teng Sha Ho Military Base, in Liaoning, China. The targeted base was just outside of Dalian, a large city that has traditionally been home to many Chinese military bases.

The effects were much more devastating than the atomic bombs at Hiroshima and Nagasaki. Big Boy killed 150,000 Chinese soldiers and military personnel and an additional 50,000 civilians. The base was the launching point for Chinese reinforcements, and was also undergoing a construction project to build an air base.

Teng Sha Ho Military Base was 949 miles from Okinawa's Kadena AFB. It is 222 miles from Pyongyang and 558 miles from Seoul.

Warfare Post-Atomic Bomb

China Pushed Back

Chinese Atom Bomb Propaganda

Chinese Propaganda after the Atom Bomb

With the loss of 150,000 Chinese troops which were readying to deploy and reinforce the Chinese position, the United States quickly put in 150,000 of their own reinforcements, and broke through the Communist lines at Kosong, a city on the west coast of the Korean Peninsula.

From Kosong, the Allied army moved north, and fought a large battle at Wonsan, which put the city into Allied hands once again. With most fighting going on in the eastern part of the Peninsula, Ridgway took all troops who were defending the South and the occupied regions of North Korea, and pushed them against the western half of the Korean Peninsula.

On to Pyongyang

Pyonnyang Capture

US Troops Taking Pyongyang

Needed to win this offensive because of its immense risk, Ridgway quickly moved his men north, and took Haeju, where the war began. With the Communist forces being divided into two sides of the Peninsula, the Allied forces pushed the advantage even further. On May 15, Sariwong fell to the Allies, and by May 30, 1951 Hamhung on the east and Nampo on the west fell to the Allies.

While the UN forces on the western side of the Korean Peninsula barraged Pyongyang in order to reduce resistance, the US army on the eastern side of the Peninsula reached Sinpo and fought a brief, victorious battle at Tanchon. Pyongyang fell to the the Allies on June 4.

China Withdraws

Once Pyongyang fell to the Allies, and after losing up to 750,000 troops, the People's Republic of China agreed to an armistice with the United States. The main reasons are the fear of an Allied invasion of China, and the fear of rebellions in Tibet. While Mao Zedong never publicly admitted to any of these reasons (his official reason was the Chinese needed a period of peace after constant fighting), it is widely accepted that this was the case.

In a letter to Zhou Enlai, the Chinese General-in-Charge, Mao did say,

The losses we have taken from the Americans are too great to maintain adequate defense of our nation. We cannot risk the UN invading us, an attack by Chiang Kai-shek's rebels, or an external threat, like Mongolia. We must make immediate preparations to leave the war as quietly as we entered the war.

North Korea Falls

With all of the Chinese troops pulled out of Korea by June 7, 1951, the UN Forces had a drastically easier job fighting only the North Koreans. The North Koreans were not as adequately equipped as the US Forces, and many openly deserted to avoid being taken prisoner by Sygman Rhee's South Koreans, who were often more violent that the US troops.

On the west coast of Korea, Allied forces took the city of Pyongsong on June 6, and then continued moving north at a rapid pace. Following existing roads, the Americans made it to Sinuiji with very little resistance. By this point, the North Koreans had been put under extremely harsh conditions in order to support the war effort, so they often times welcomed the South Koreans.

On the east coast of the Peninsula, the North Korean army fell back to Chongjin, much like when UN forces took most of North Korea in December 1950. Since the city had been well-provisioned at that time, the siege of the city was the final difficult battle of the Korean War from the American perspective. The city fell to the US on June 8.

After Chongjin fell to the US, Kim Il-Sung fled to Vladivostok, Russia, USSR, only 140 miles away. With both of the coastlines taken, the Allied forces then moved inland, and were met by reserves coming up from South Korea. With the ceremonial surrender of Kanggye, on the one-year anniversary of the war, June 25, 1951, the Korean War was finished.

Result of War

Conference at Seoul (6-2-5)

Truman and Rhee at the Seoul Conference

Seoul Conference

Following the Surrender at Kanggye, negotiations began to reform Korea into a unified, and industrializing nation. Principle topics for the conference were how to unify the two Koreas, how to create a sense of Korean nationalism, how to repair the damaged Korean economy, and how to prevent the spread of Communism in Korea.

The main attendees were from South Korea, North Korea, the US, the UK, the Republic of China, and Japan. Most nations' Head of Government attended. The main exception was the UK, because Clement Atlee was facing re-election. (His Labour Party would lose to Churchill's Conservative Party.) The following is a list of the leaders of each nation's delegation.

  • From South Korea - Syngman Rhee (President of the Republic of Korea)
  • From North Korea - Kim Yong-ju (Brother of Kim Il-Sung)
  • From the United States - Harry S. Truman (President of the US)
  • From the United Kingdom - Sir Vyvyan Holt (Ambassador to South Korea and Former P.O.W.)
  • From the Republic of China - Chiang Kai-Shek (President of the Republic of China)
  • From Japan - Shigeru Yoshida (Prime Minister of Japan)

The Conference convened on July 1, 1951, and ended on November 1, 1951, with the signing of the treaty by all attending dignitaries.

Treaty of Seoul

The Treaty of Seoul was the official treaty which ended hostilities between the North Korean and the allied UN forces. While the North had been under occupation since late June, North Korea and South Korea did not combine until the ratification of this treaty in the South Korean and American governments, which effectively made the treaty universally accepted.

The Treaty of Seoul is called for the unification of Korea, under the Republic of Korea. The capital stayed in Seoul, and the elected officials of the South were to remain in power until a new Constitution was approved by plebiscite before January 1, 1953.

The US was granted 300 sq km of land along the Korean-Chinese border, in order to build a state-of-the art military base, which would serve as a launching point of campaigns in Northeast Asia. Furthermore, all nations agreed to a joint-military action agreement for Asia, which is often cited as the source of the Second Chinese Civil War.

Korea Post-Unification


Syngman Rhee, leader of Unified Korea

With the entrance of North Korea into the Republic of Korea (formerly South Korea), the first steps taken by Syngman Rhee was the drafting of the Constitution of 1952. According to the terms of the Treaty of Seoul, the new government had to be established by 1953.

The vast majority of North Koreans were relatively not upset over the regime change, considering a dictatorship under Rhee with American backing to be very much the same situation as being in a dictatorship under Kim Il-Sung with Soviet and Chinese backing. With that being said, in general, conditions improved for North Koreans after the war.

Displaced families, who had sometimes been separated since Japanese occupation in 1910, were reunited, and businesses emerged in the North that were previously government-owned. The new Constitution was ratified Monday, May 5, 1952, less than a year after the war ended.

Notably, the new Constitution established a new popular and direct election of the President, which made it easy for Rhee to be reelected in the elections that were then held on December 1, 1952.