The (Chinese) People's Volunteer Army (PVA or CPVA; simplified Chinese: ; traditional Chinese: ; pinyin: Zhōngguó Rénmín Zhìyuàn Jūn) was the armed forces deployed by the People's Republic of China during the Korean War. Although all units in the Chinese People's Volunteer Army were actually transferred from the People's Liberation Army (the official name of the Chinese armed forces) under orders of the Chinese Communist Party, the People's Volunteer Army was separately constituted in order to prevent an official war with the United States. The People's Volunteer Army entered Korea on October 19, 1950, and completely withdrew by October 1958. The nominal commander and political commissar of the CPVA was Peng Dehuai before the ceasefire agreement in 1953, although both Chen Geng and Deng Hua served as acting commander and commissar after April 1952 due to Peng's illness. The initial (October 25 – November 5, 1950) units in the CPVA included 38th, 39th, 40th, 42nd, 50th, 66th Army and eventually about 3 million Chinese military personnel served in Korea by 1953.
Although the United Nations forces were under United States command, this army was officially a UN "police" force. In order to avoid an open war with the US and other UN members, the People's Republic of China deployed the People's Liberation Army (PLA) under the name "volunteer army". The name was also an homage to the Korean Volunteer Army that had helped the Chinese communists during the Second Sino-Japanese War and the Chinese Civil War, and it managed to deceive the US intelligence about the size and nature of the Chinese forces that entered Korea. Technically speaking, the PVA was the PLA's North East Frontier Force (NEFF), with other PLA formations transferred under NEFF's command as the Korean War dragged on.