How about this: Yuan Shikai's plan to set himself up as emperor doesn't backfire quite as badly as in OTL; while the bulk of the Beiyang Army breaks from him, he retains the loyalty of a few retainers, among them Feng Guozhang and Duan Qirui, who help him impose his rule on the east-central provinces (the territory held by the Zhili clique at the beginning of the Warlord Era in OTL). While he rules for less than a year, upon his death, his son Keding inherits the throne and is kept as a convenient figurehead by the military strongmen who are actually in charge. In the following years, this neo-imperial China fails to extend its rule to the other provinces, but manages to consolidate its home base.
Meanwhile, Manchuria is taken over by Zhang Zuolin, who rules as a warlord but finds himself unable to prevent creeping Japanese encroachment throughout the 1920s. In order to resist all-out invasion, he calls on the Soviets for help in 1932, and Stalin is all too happy to seize the opportunity to retake the region lost to Japanese influence in 1905. After three years of war, Japan is forced to leave Manchuria alone, but Zhang realizes to his dismay that his regime has by then been thoroughly infiltrated by Soviet agents and local Communists. He is deposed in 1936 and Manchuria becomes a formally independent country called the People's Republic of China, in fact a Soviet puppet state.
This leaves southern China, where Nationalist influence is strongest. From its base in Guangdong, the GMD takes control of neighboring provinces. An attempt to overthrow the neo-imperial regime to the north fails when the Northen Expedition is repelled, and the Nationalists decide to instead consolidate their local rule while waiting for another opportunity to reunify China.
Voilà!