Chinese Civil War

The Chinese Civil War was fought intermittently between the Kuomintang (KMT), led by Chiang Kai-shek, and the Chinese Communist Party (CCP), led by Mao Zedong, for control of mainland China. It is conventionally divided into two phases: an initial period beginning in 1927, when the KMT broke its First United Front with the CCP and launched the Shanghai Massacre, and a resumed phase from 1946 to 1949 after the Second Sino-Japanese War.

During the first phase, CCP forces were driven from their southern base areas, culminating in the Long March (1934–1935) to Yan'an in Shaanxi. The two parties suspended hostilities to form a Second United Front against Japan following the Xi'an Incident of December 1936 and the full-scale Japanese invasion in 1937, though clashes such as the 1941 New Fourth Army Incident continued.

After Japan's surrender in 1945, US-mediated talks (notably the Marshall Mission of 1945–47) failed to produce a coalition government. Full-scale fighting resumed in 1946. Despite initial KMT territorial advantages and substantial US military aid, the People's Liberation Army won decisive campaigns in 1948–49, including the Liaoshen, Huaihai, and Pingjin campaigns. On 1 October 1949, Mao proclaimed the People's Republic of China in Beijing; Chiang's government retreated to Taiwan in December 1949.

No formal peace treaty was ever signed, and the conflict's unresolved status underpins the ongoing Taiwan Strait question. The PRC continues to claim Taiwan as a province, while the Republic of China government on Taiwan maintained its claim to represent all of China until political liberalization in the 1990s. The war also shaped Cold War alignments in Asia, contributed to the 1950 Sino-Soviet Treaty of Friendship, and influenced US containment policy, including the deployment of the Seventh Fleet to the Taiwan Strait in 1950.