対華21カ条要求
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. Under the Beiyang Government, China remained fragmented and was unable to resist foreign incursions. For the purpose of unifying China and defeating the regional warlords, the Kuomintang (KMT, alternatively known as the Chinese Nationalist Party) in Guangzhou launched the Northern Expedition from 1926 to 1928 with limited assistance from the Soviet Union.