Chinese Communist forces, defeated in Kiangsi, retreated north and west 2,500 to 3,000 miles through mountianous country to Shensi; in battle with Komintang forces as they retreated, the Communists suffered 150,000 to 170,000 casualties and defections of the approximately 200,000 who started from Kiangsi; most Communist leaders who later took power (1949) were on this journey, including Zhu De, Mao Zedong, and Zhou Enlai.
 After the Long March, the Chinese Communists made their headquarters at Yenan, in Shensi, as they settled into a decade of guerrilla war against the Japanese and sometimes against the Kuomintang as well.
The epic Long March of his Red Army and its supporters, which began in October 1934, would ensure his place in history. Forced to evacuate their camps and homes, Communist soldiers and government and party leaders and functionaries numbering about 100,000 (including only 35 women, the spouses of high leaders) set out on a circuitous retreat of some 12,500 kilometers through 11 provinces, 18 mountain ranges, and 24 rivers in southwest and northwest China. During the Long March, Mao finally gained unchallenged command of the CCP, ousting his rivals and reasserting guerrilla strategy. As a final destination, he selected southern Shaanxi Province, where some 8,000 survivors of the original group from Jiangxi Province (joined by some 22,000 from other areas) arrived in October 1935. The Communists set up their headquarters at Yan'an, where the movement would grow rapidly for the next ten years. Contributing to this growth would be a combination of internal and external circumstances, of which aggression by the Japanese was perhaps the most significant. Conflict with Japan, which would continue from the 1930s to the end of World War II, was the other force (besides the Communists themselves) that would undermine the Nationalist government.