What happened
The Central Red Army broke out of the Jiangxi Soviet in October 1934. About 86,000 set out, and the Xiang River crossing cost roughly half of them. The Zunyi Conference of January 1935 elevated Mao Zedong’s military leadership. The storied route — four crossings of the Chishui River, the Luding Bridge over the Dadu (a heroic account that is party canon, though historians debate its details), the snow mountains and the high grasslands — brought several thousand survivors to northern Shaanxi in October 1935; other field armies joined through October 1936, at the junction at Huining.
Background
Chiang Kai-shek’s fifth encirclement campaign had succeeded, forcing the Red Army to abandon its encircled southern base areas.
Consequences
The Communist Party survived, with Yan’an as its base, and Mao’s leadership was consolidated. The First Front Army’s route is traditionally counted as 25,000 li — about 12,500 km by the traditional count, with modern estimates lower — and the march became the founding epic of PRC memory.