The Korean War

The Korean War was a war on the Korean peninsula that began at dawn on 25 June 1950, when North Korean forces invaded illegally across the whole length of the 38th parallel.

It lasted a little over three years, but what makes it hard to follow is not its length — it is that the front line reversed several times. Seoul did not change hands once; it changed hands repeatedly. Knowing that sequence makes the displays at the War Memorial far easier to read.

Why the line was there in the first place is covered in the division of Korea.

At a glance

Dawn, 25 June 1950
North Korean forces began a full invasion across the entire 38th parallel.
Sixteen countries
A UN resolution delegated supreme command to the United States, and forces from 16 nations came under the UN commander.
15 September, Incheon
US X Corps and some 5,000 ROK marines landed at Wolmido before dawn.
27 July 1953
The armistice agreement halted the war.

The first days — Seoul falls in two

At dawn on 25 June 1950, North Korean forces began a full invasion across the whole 38th parallel.

Speed explains the first phase. The surprise attack fell on a South Korea that was politically unstable and undefended, and by 27 June Seoul had already been occupied; by 3 July the advance had crossed the Han River and was continuing south.

The international response moved at the same pace. On the 25th the United States convened an emergency session of the UN Security Council, which declared the armed attack an "act of aggression" and adopted a resolution calling for an immediate halt and withdrawal to the 38th parallel.

On 7 July the Security Council adopted a resolution delegating supreme command to the United States, and MacArthur was appointed commander of the UN forces. With that, forces from 16 countries that had sent army, navy, air and ground units came under the UN commander.

The US 24th Infantry Division, stationed in Japan, moved immediately, but could not turn the situation, and UN forces held a defensive line on the Nakdong River based on Busan while looking for a chance to counterattack.

The Incheon landing was a plan that had been refused

The landing is famous not only because it worked. It was rejected first.

Planning began on 15 July, only weeks into the war. MacArthur submitted it to the Joint Chiefs of Staff and was refused, on the grounds that it would disperse forces and that Incheon was the least suitable terrain there was for an amphibious landing. The preferred alternative was to reinforce the Busan perimeter.

MacArthur's counter-argument had three parts: that Incheon's tidal range of 9 metres still left six usable hours for a landing; that North Korean forces were concentrating on taking Busan and had therefore left Incheon lightly defended; and that retaking the capital quickly would have a large psychological effect on soldiers and civilians alike. He did not give way, and obtained the President's approval on 8 September.

Before dawn on 15 September, X Corps — the US 1st Marine Division and 7th Division — together with some 5,000 ROK marines landed at Wolmido in Incheon, and took Incheon the next day. The US 7th Division pushed south and met UN forces coming north at Osan, cutting the North Korean army in two.

UN forces entered Seoul on 26 September, and once the city was fully recovered a ceremony marking its recapture was held on 29 September.

And then it reversed again

What happened after that reversal is what made this a three-year war.

The situation, which had been turning around through the intervention of the international community under UN resolutions, went back into stalemate with the intervention of Chinese forces.

The question of operating north of the 38th parallel is on the record too. The UN Security Council resolution of 7 July 1950 gave the purpose of the intervention as to "repel the armed attack of North Korea and restore international peace and security on the Korean peninsula", and whether that matched South Korea's stated goal of unification was contested. The US government authorised military operations north of the 38th parallel on 27 September, while strictly forbidding ground and air forces from crossing the Soviet or Chinese borders, in order to prevent a general war between the great powers.

Then the armistice agreement of 27 July 1953 stopped the war. The encyclopedia sums up the result: it inflicted great loss on the whole Korean people, and the division subsequently became more entrenched, with the ceasefire still continuing.

Where the war is on display

The places that deal with the war are different in character.

Seoul's War Memorial of Korea sets out the course of the war and the countries that fought in it. The national flags along its entrance walkway connect directly to the fact of those sixteen contributing nations.

Busan offers another angle. Because Busan was the anchor of the Nakdong defensive line, traces of the war years are still in the fabric of the city. The Provisional Capital Memorial Hall covers the period when the government moved to Busan, and the UN Memorial Cemetery is the burial ground for the war dead of the contributing nations.

Seen together, the three convey — as places rather than as explanation — that this was not only Korea's war.

Where to see the Korean War

Frequently asked questions

When did the Korean War start and end?

It began at dawn on 25 June 1950 with the North Korean invasion, and was halted by the armistice of 27 July 1953. That is a ceasefire rather than an end to the war, and the state has continued since.

How many countries took part?

Forces from 16 countries that sent army, navy, air and ground units came under the UN commander. Supreme command was delegated to the United States by the Security Council resolution of 7 July 1950.

When did Seoul fall and when was it retaken?

It was occupied on 27 June 1950. After the Incheon landing, UN forces entered on 26 September and a recapture ceremony was held on 29 September.

What was special about the Incheon landing?

It was first refused, on the grounds that it would disperse forces and that Incheon was the least suitable terrain for a landing. MacArthur pressed the case — including that the 9-metre tidal range still left six usable hours — and obtained presidential approval on 8 September, with the landing on 15 September.

Why did the war last three years?

Because the situation, which had turned around after the UN intervention, went back into stalemate once Chinese forces intervened.