 At this point the Chinese portion of Shanghai was controlled by Sun Chuanfang, one of the militarists targeted by the North Expedition.Distracted by fighting with the NRA and defections from his army, Sun reduced his forces in Shanghai, and the Communists, whose party headquarters was located in Shanghai, made three attempts to seize control of the city, later called "the three Shanghai Uprisings", in October 1926, February 1927 and March 1927.Zhou was transferred to Shanghai to assist in these activities, probably in late 1926.