Communist-controlled China (1927–1949)

Communist-controlled China or the Revolutionary Base Area, officially called the Soviet Zone from 1927 to 1937, and the Liberated Zone from 1946 to 1949, was the part of the territories of China controlled by the Soviet-backed Chinese Communist Party (CCP) from 1927 to 1949 during the Republican era and the Chinese Civil War with Nationalist China.

There were six soviet areas from 1927 to 1933: the Jinggang Mountains, the Central Soviet in Eastern Jiangxi on the border of Fujian, the Eyuwan Soviet, Xiangexi (West Hubei and Hunan), and Xianggan (Hunan-Jiangxi). The first soviet was the Hailufeng Soviet created in 1927. The Central Soviet was the main base of the CCP where its leader Mao Zedong issued a directive on 1 September 1931 for the Central Soviet to mass mobilize the region as a base area. As problems occurred over being able to control territories outside the Central Soviet, by 1933 a full transfer of Communist forces to the Central Soviet was achieved. In 1931, the disconnected areas controlled by the Communists were declared the Chinese Soviet Republic.

Somewhat separately from the Chinese Soviets, there was a pro-Soviet Union protectorate ruled by Sheng Shicai following the Soviet invasion of Xinjiang. Sheng switched between alliance and hostility to the communists in the east.

Upon the intervention of the Soviet Union against Japan in World War II in 1945, USSR forces invaded the Japanese client state of Manchukuo. Mao Zedong in April and May 1945 had planned to mobilize 150,000 to 250,000 soldiers from across China to work with forces of the Soviet Union in capturing Manchuria. After the end of the war, the communists controlled one-third of the territory of China. From 1945 to 1949, in the Chinese Communist Revolution, the Communists captured all Chinese territory except for Taiwan and the fragments of Fujian, and established the People's Republic of China that exists today.