Eyuwan Soviet in the context of Fourth encirclement campaign against the Eyuwan Soviet

The Chinese Soviet Republic (CSR) was a state within the Republic of China, proclaimed on 7 November 1931 by Chinese Communist Party (CCP) leaders Mao Zedong and Zhu De in the early stages of the Chinese Civil War. The discontiguous territories of the CSR included 18 provinces and 4 counties under the Communists' control. The CSR's government was located in its largest component territory, the Jiangxi Soviet in southeastern China, with its capital city at Ruijin. Due to the importance of the Jiangxi Soviet in the CSR's early history, the name "Jiangxi Soviet" is sometimes used to refer to the CSR as a whole. Other component territories of the CSR included the Minzhegan, Xianggan, Xiang'egang, Honghu, Xiang'echuanqian, Eyuwan, Eyushan, Shaanxi-Gansu, Sichuan-Shaanxi, and Hailufeng Soviets.

Mao was both CSR state chairman and prime minister; he commanded the state and its government. Mao's tenure as commander of a "small state within a state" gave him experience in mobile warfare and peasant organization, which helped him lead the Chinese Communists to victory in 1949.

The Dabie Mountains (traditional Chinese: 大別山; simplified Chinese: 大别山; pinyin: Dàbié Shān) are a major mountain range located in central China. Running northwest-to-southeast, they form the main watershed between the Huai and Yangtze rivers. The range also marks the boundary between Hubei Province (near Tingqian town) and its neighbors of Henan (to the north) and Anhui (to the east). During the late 1920s and early 1930s, the Dabie Mountains were a stronghold of the Chinese Communist Party and the location of the Eyuwan Soviet.

The western part of the Dabie Mountains has a low elevation of only 1,000–1,300 feet (300–400 meters), though there are a few peaks rising to 3,000 feet (910 meters). The eastern part is higher, averaging more than 3,300 feet (1,000 meters). The highest peak is Baimajian at 1,777 meters (5,830 feet), with several others topping 5,000 feet (1,500 meters) including the 1,729.13 meters (5,673.0 ft) high Tiantangzhai.

The Chinese Communist Party (CCP) had sphere of influence within the Republic of China from 1927 to 1949 during the Chinese Civil War, collectively called revolutionary base areas. They were also known as the Soviet Zone from 1927 to 1937 during the early stages of the Chinese Civil War, the Anti-Japanese Base Areas during the Second Sino-Japanese War, and the Liberated Zone during the final Stages of the Civil War from 1946 until the founding of the People's Republic of China in 1949.

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 CCP forces to the Central Soviet was achieved. In 1931, the disconnected areas controlled by the CCP were declared the Chinese Soviet Republic (CSR).