Following North Korea’s attack on South Korea on 25 June 1950, President Harry Truman ordered General MacArthur, commander of all US forces in the Far East to support the ROK, Republic of Korea, and 21 members of the UN committed themselves to support South Korea. MacArthur immediately provided air support and deployed a naval blockade of North Korea and, at the end of June, Truman authorized the use of US ground forces. Over the next two months US forces arrived in Korea, fighting defensive battles and reinforcing what was now the Pusan Perimeter. The UN counterattack began on the dawn of 15 September, with a seaborne landing at Inchon on the west coast of Korea, well behind the North Korean lines of supply. Simultaneously, a breakout from the perimeter was launched, heading northwest for Seoul, with the US 1st Cavalry division in the lead. Seoul was liberated on 26 September. The North Korean Army disintegrated; 120,000 prisoners were taken, while thousands more fled north using narrow mountain tracks in their attempt to escape. On 1 October ROK troops crossed the 38th Parallel and, with UN agreement, the advance continued in the face of growing anger from the newly established communist government of China. The UN for its part forbade any airstrikes north of the Yalu River, the border between Korea and Manchuria, part of China. On 20 October Pyongyang, the northern capital, was taken, with the ROK’s 6th division arriving at the Yalu River on the 26th. Chinese units had been gathering north of the border for some time, and a surprise counterattack by Chinese troops up to 1 November revealed they had even crossed the border. With this new and shocking information UN forces were ordered to consolidate their position.
— OR —