The Battle of Chosin Reservoir, also known as the Chosin Reservoir Campaign or the Battle of Lake Changjin (Korean: 장진호 전투), was a key battle during the Korean War. The name "Chosin" comes from the Japanese pronunciation rather than the Korean one.

 

The battle began about a month after China entered the war, sending the People's Volunteer Army (PVA) 9th Army to infiltrate northeastern North Korea. On November 27, 1950, Chinese forces launched a surprise attack on the US X Corps, led by Major General Edward Almond, in the Chosin Reservoir area. A brutal 17-day battle in freezing weather followed.

 

Between November 27 and December 13, 30,000 United Nations troops, later called "The Chosin Few," under the command of Major General Oliver P. Smith, were surrounded by 120,000 Chinese troops led by Song Shilun, following orders from Mao Zedong to destroy the UN forces. Despite being encircled, the UN troops managed to break out and retreat to the port of Hungnam.

 

Both sides suffered heavy casualties, with the Chinese being hit especially hard, not just from battle but also from the extreme cold. Afterward, the US Eighth Army withdrew from northwest Korea, and the X Corps evacuated from Hungnam, marking the complete withdrawal of UN forces from North Korea.