17. The Chinese Offensive in Korea, November-December 1950
Following the US landings at Inchon in Korea, the US and South Korean troops rapidly pushed the North Korean army up the peninsula, nearing the Yalu River – the border with China – by October. After the Chinese obtained support for the operation from Stalin and the USSR, Chinese troops entered Korea in late October, 1950. More than 200,000 Chinese troops attacked United Nations troops, with support from Soviet fighters providing air cover. Officially the Soviet Union stated that the airplanes were flown by Chinese and North Korean pilots, but later evidence unveiled the fact that Soviet fighter pilots and bombers participated in the invasion by the Chinese. The initial invasion stopped the advances of the United Nations forces, which were almost entirely made up of US and South Korean troops. The Chinese then launched an offensive of their own.
When the United States Eighth Army launched what it called its Home by Christmas offensive in late November, the Chinese counterattacked in a prepared multi-pronged assault, which sent the surprised and outnumbered Americans into a lengthy retreat down the Korean Peninsula. The retreat was the longest in the history of the United States Army. By the end of December American President Harry Truman declared a National State of Emergency. The Chinese second phase offensive, which included the Battle of Chosin Reservoir and six weeks of heavy fighting while retreating before the Chinese and the North Koreans led to over 4,500 American combat deaths as well as deaths from the bitter cold. By January, the United Nations forces were back in the Pusan Perimeter where they had been before the Inchon landings, and the gains of the invasion were lost.