The Northern Expedition was a military campaign launched by the National Revolutionary Army (NRA) of the Kuomintang (KMT) against the Beiyang government and other regional warlords in 1926. The purpose of the campaign was to reunify China, which had become fragmented in the aftermath of the Revolution of 1911. The expedition was led by Generalissimo Chiang Kai-shek, and was divided into two phases. The first phase ended in a 1927 political split between two factions of the KMT: the right-leaning Nanjing faction, led by Chiang, and the left-leaning faction in Wuhan, led by Wang Jingwei. The split was partially motivated by Chiang's Shanghai Massacre of Communists within the KMT, which marked the end of the First United Front. In an effort to mend this schism, Chiang Kai-shek stepped down as the commander of the NRA in August 1927, and went into exile in Japan.

The Shanghai massacre of 12 April 1927, the April 12 Purge or the April 12 Incident as it is commonly known in China, was the violent suppression of Chinese Communist Party (CCP) organizations and leftist elements in Shanghai by forces supporting General Chiang Kai-shek and conservative factions in the Kuomintang. Following the incident, conservative KMT elements carried out a full-scale purge of communists in all areas under their control, and violent suppression occurred in Guangzhou and Changsha. The purge led to an open split between left-wing and right-wing factions in the KMT, with Chiang Kai-shek establishing himself as the leader of the right-wing faction based in Nanjing, in opposition to the original left-wing KMT government based in Wuhan, which was led by Wang Jingwei. By 15 July 1927, the Wuhan regime had expelled the Communists in its ranks, effectively ending the First United Front, a working alliance of both the KMT and CCP under the tutelage of Comintern agents. For the rest of 1927, the CCP would fight to regain power, beginning the Autumn Harvest Uprising. With the failure and the crushing of the Guangzhou Uprising at Guangzhou however, the power of the Communists was largely diminished, unable to launch another major urban offensive.