For most of the early 1920’s China was not a united country. Multiple Warlords controlled areas of the north and the Nationalists lead by Chaing Kaishek controlled a southern province. The Communist part was founded in Shanghai in 1921 and initially allied themselves with the Nationalists for a short time. In 1926 Chaing Kaishek launched the Northern Expedition to reunite China.

(The Great Courses – From Yao to Mao: 5000 years of Chinese History)