The Communists were in disarray after the Shanghai Massacre; many of its support base had been killed or arrested, and those who survived dare not show further support. The city workers would no longer be a major base of support for the CCP.
However, it was in the countryside the support for the CCP gained hold. Although a series of uprisings (directed by Stalin) failed, rural Soviets, located in remote locations, gained a foothold in remote areas. Zhu De & Mao Zedong, in Jiangxi, established the major of these Soviet bases [ firstly at Jinggangshan, then later in Ruijin]. At its peak, it governed approximately 4,000,000 people. Land, Tax and Social Reforms all helped gain the support of the people, but it was the work of the Red Army that was most impressive. The Red Army Code, and the Army's assistance in helping peasants in the countryside whilst not on active duty, further cultivated support for the CCP. The local populations, so often mistreated by Imperial, Warlord or GMD armies, saw the CCP as a more positive alternative.