Why did the Chinese communists leave the Jiangxi Soviet in 1934?

The Chinese communists abandoned the Jiangxi Soviet in October 1934 primarily because they were being overwhelmed by the fifth of Chiang Kai-shek’s military encirclement campaigns.12

While the communists had successfully repelled the first four campaigns using Mao Zedong’s mobile infiltration and guerrilla warfare tactics, the situation changed during the fifth campaign. By this time, the Chinese Communist Party’s Central Committee had removed Mao from military leadership and shifted to a strategy of fixed positional warfare.12

Facing approximately 700,000 Nationalist troops and a series of cement blockhouses, the communist forces suffered heavy losses and were nearly annihilated. To avoid total destruction, the remaining 86,000 troops broke through Nationalist lines and began the Long March to relocate their base to northwestern China.12