Meanwhile, the CCP split into several groups: some fled to Moscow in exile, and “White Area CCP" stayed in cities, hiding from gangs aligned with the KMT, while "Red Area CCP" went to the mountains and staged local uprisings in Nanchang and then in Hunan. Because of the events of April 1927, the Comintern broke ties with the KMT. The left-wing leader of the KMT Wang Jingwei and his allies moved the Nationalist government from Guangzhou to Wuhan, while Chiang's rival right-wing, anti-Communist KMT regime was established at Nanjing in April of 1927. The Autumn Harvest Uprising, led by Mao Zedong, erupted in Hunan and Jiangxi provinces in September 1927. The peasant army, led by Mao, caused radical upheaval for several weeks, leaving the landowning classes trembling. When the uprising was defeated by the KMT, Mao was forced to retreat to Jiangxi province. 

The Communists led by Mao Zedong, using guerrilla warfare in the mountain regions against KMT attacks, merged with another group led by Zhu De. The Jiangxi Soviet in southern China, located between Fujian and Hunan provinces, was a rural communist base, established in November 7, 1931 with the first National Congress of the Chinese Soviet Republic. The headquarters of the Chinese Soviet government was located at the town of Ruijin. Mao Zedong was elected both the Head of State and the Head of Government of the Chinese Soviet Republic. CCP membership grew as more peasants were recruited. In line with the Communists' signature social program for land reform, the lands of the wealthy were confiscated and distributed to the peasants.

The Jiangxi Soviet was attacked by nationalist KMT forces during their Encirclement Campaigns of the early 1930s, but the first few campaigns were thwarted by the Communists' guerilla strategies. However, the end of the Jiangxi Soviet came in 1934, when KMT forces led by Chiang Kai-shek eventually forced the Red Army to retreat, on the Long March, to Shaanxi in northern China. 

Principles of the Red Army 

"The enemy advances, we retreat. The enemy camps, we harass. The enemy tires,  we attack. The enemy retreats, we pursue."

Because the Red Army was poorly equipped, soldiers employed guerilla tactics. The communists adhered to the "fish in water" theory: guerillas were the "fish" and the peasants were the "water." The Red Army must, therefore, lead by example, and instead of coercing the masses, live and work among people. There were also strict rules of behavior for the Red Army in regard to the treatment of civilians. Rules included: obey all orders, refrain from taking anything, speak politely, and turn in everything captured. In addition the troops performed normal civilian functions such as farming and teaching.