皖系
Although it appeared that Zhili's power was secure for the time being, a crisis in the south soon precipitated another showdown with the Fengtian clique. The crisis was over the city of Shanghai, the commercial powerhouse of the nation. It was part of the province of Jiangsu, under Zhili control, but actually administered by Zhejiang, ruled by the remnants of the Anhui clique. When the Zhili clique demanded the return of Shanghai to their administration they were refused and fighting soon broke out. Zhang Zuolin in Manchuria and Sun Yat-sen, then in Guangdong, quickly declared their support for the Anhui clique and geared up for war. Wu Peifu dispatched his subordinate and protégé Sun Chuanfang to the south to deal with the Anhui clique and any attack that may have come from Sun's Kuomintang forces, while Wu himself prepared to face off again with Zhang's Fengtian army.