This map is part of a series of 9 animated maps showing the history of The Cold War and Confrontation between East and West 1947-1991.
In 1945, the Soviets and the Americans decided to co-administer Japanese-occupied Korea, establishing the 38th parallel as the frontier between their respective zones of influence.
During the years that followed, numerous disagreements between the superpowers led to the division of the Korean Peninsula into two separate countries: the communist Democratic People’s Republic of Korea in the north, ruled by Kim Il Sung, and the Democratic Republic of Korea in the south, governed by Syngman Rhee.
It was not long before their diametrically opposed ideologies lead to repeated tensions and border incidents.
At dawn on 25 June 1950, North Korean troops crossed the border and marched rapidly on Seoul.
The American President, Harry Truman, announced that the United States would intervene to stop this invasion.
In the absence of the Soviet Ambassador, the UN Security Council passed several resolutions condemning this aggression by North Korea and handing command of a UN military force to the United States.
The North Korean troops reached the southernmost point of the Peninsula in August 1950. The South Korean army, together with the 8th US Army, managed to stabilize the front near Pusan just as the first UN troops arrived.
On 15 September, General MacArthur, head of the UN forces, launched a counter-offensive behind enemy lines by landing at Inchon, Seoul’s port city.
With Operation Chromite, the UN force successfully forced the North Korean troops to retreat and continued to move northwards, capturing Pyongyang on 19 October and reaching the Korean-Chinese border on 26 October.
China reacted with a massive mobilization of its People’s Volunteer Army. In November, nearly 200,000 Chinese volunteer soldiers crossed the Korean frontier and pushed the UN forces back beyond Seoul, which fell once more in January 1951.
The UN army’s counter-offensive in March succeeded in re-taking Seoul and in stabilizing the front around the 38th parallel.
Meanwhile, the lack of a decisive victory for either side led to a stalemate.
In the summer of 1951, peace negotiations began, but no treaty was concluded until after the death of Stalin two years later.
The armistice was signed on 27 July 1953 in the village of Panmunjom.
The United States and the USSR recognized the existence of the two Koreas and, while waiting for the signature of a peace treaty, established a 4-kilometre-wide demilitarized zone along the armistice line.
The damage caused by the war was massive: more than 3.5 million dead and many towns destroyed. Nevertheless, the Korean War did not degenerate into a full-scale war, and the two superpowers managed to avoid open conflict. In spring 1951, President Truman was committed to the policy of ‘containment’, rejecting General MacArthur’s proposal to launch aerial bombing attacks over Chinese territory. Their public disagreement caused Truman to relieve the General of his command.