In 1932 Zhang led the 4th Red Army into
Sichuan and set up another base. Slowly he turned it into a prosperous autonomous region by way of land reform and enlisting the support of locals. However, once the prosperity was in reach, Zhang repeated the Stalinist style purges again, as a result, he and the Red Army lost the popular support, and was driven from the Red base and had to start their part of the
Long March. In 1935 Zhang and his troops of more than 80,000 reunited with Mao's 7,000 troops in Sichuan after the Long March. It was Zhang's arrogance due to his superior strength at this time which sowed the seeds of conflict between the two men. It was not long before Mao and Zhang were locked in disagreements over issues of strategy and tactics, causing a split in the Red Army. The main disagreement was the Zhang's insistence on moving southward to establish a new base in the region of Sichuan that are populated by minorities. Mao correctly pointed out the flaws of such move, pointing out the difficulties to establish any communist base in regions where the general populace was hostile, and insisted on moving northward to reach the communist base in
Shaanxi.
Zhang tried have Mao and his followers arrest and killed if needed, but his plan was foiled by his own staff member
Ye Jianying and
Yang Shangkun, who fled to Mao's headquarter to inform Mao about Zhang's plot, taking the all of the code books and maps with them. As a result, Mao immediately moved his troop northward and thus escaped arrest and possible death.
Zhang decided to carry out his plan on his own, with disastrous results: over 75% of his original 80,000 + troops were lost in his adventure. Zhang was forced to admit defeat and retreat to the communist base in Shaanxi, as Mao had predicted. More disastrous than losing most of his troops, the failure discredited Zhang among his own followers, who turned to Mao. Furthermore, because all of the code books were obtained by Mao, Zhang lost contact with Comintern while Mao was able to establish the link, this coupled with the fact of Zhang's disastrous defeat, discredited Zhang within Comintern, which begun to give greater support for Mao.
Zhang's remaining troops of 21,800 were later annihilated in 1936 by the superior force of more than 100,000 combined troops of warlords
Ma Bufang,
Ma Hongbin and
Ma Zhongying during efforts to cross the
Yellow River and conquer Ma's territory. Zhang lost the power and influence to be able to challenge Mao and had to accept his failure as a result of the disaster which only left him 427 surviving troops from the original 21,800.