In January 1915, with Europe consumed by World War I, Japan presented the Twenty-One Demands to the Republic of China—an audacious bid to convert China into a Japanese protectorate. The demands were grouped into five categories.
Japan sought formal recognition of its seizure of German rights in Shandong Province (Qingdao, Jiaozhou Bay railway, mining rights)—effectively legitimizing wartime conquest.
Goal: de facto control of Northeast China.
Joint Japanese–Chinese operation of the strategic Hanyeping works (Hubei/Hunan)—giving Japan sway over China's heavy industry.
China would not cede or lease any coastal territory to any power except Japan—a "most favored nation" clause for territorial grabs.
This group would have made China a de facto Japanese satellite.
China rejected Group V entirely and negotiated on the rest. Under U.S. and British diplomatic pressure, Japan dropped Group V in the final Treaty of May 25, 1915. China conceded Shandong, Manchurian rights, and Hanyeping—but preserved nominal sovereignty.
The Twenty-One Demands were a watershed: the moment Japan openly demanded hegemony over China—and the moment Chinese nationalism coalesced in resistance.