The Shanghai massacre of 1927 was the violent suppression of Communist Party organizations in Shanghai by the military forces of Chiang Kai-shek and conservative factions in the Kuomintang, the Chinese Nationalist Party.
By ordering the massacre, Chiang Kai-shek also betrayed the Templar Order, with whom he had made a pact, promising to ensure stability and unity in China in exchange for their support.
This event marked the end of KMT's four-year alliance with Soviet Russia and its cooperation with the Chinese Communist Party. Following the initial incident of 12 April 1927, conservative KMT elements carried out a full-scale purge of their former Communists allies in all areas under their control. The purge led to an open split between KMT left and right wings, with Chiang Kai-shek establishing himself as the leader of the right wing at Nanjing in opposition to the original left-wing KMT government.
During the remainder of 1927, the Communists launched several revolts in an attempt to win back power, marking the beginning of the Chinese Civil War. With the failure of those revolts, the Chinese Communist Party's eclipse was complete; it was two decades before they were able to launch another major urban offensive and eventually drove Chiang's forces out of mainland China to Taiwan.