 For example, the warlord Zhang Zuolin of Manchuria from the Fengtian clique openly cooperated with the Japanese for military and economic assistance.In 1915, Japan issued the Twenty-One Demands to extort further political and commercial privilege from China, which was accepted by Yuan Shikai.Following World War I, Japan acquired the German Empire's sphere of influence in Shandong province, leading to nationwide anti-Japanese protests and mass demonstrations in China.