The Chinese Communist Party was formed in 1921. Among its original members was Mao Zedong. Two years later, the Communists helped Sun Yat-sen reorganize the crumbling Kuomintang. In 1926, the strengthened Kuomintang, under the leadership of Chiang Kai-shek, tried to unify China under Kuomintang rule and rid the country of warlords and imperialists. Chiang purged the Communists and relied increasingly on foreign intervention. In 1928, he established a new government, but his rule was unstable. He failed to unify the country, and the Communists soon began to marshal the opposition. Mao Zedong rallied the peasants and set up opposition governments. Increasing Japanese aggression chipped away from the North and Manchuria.
On September 18, 1931, the Japanese exerted their control throughout Manchuria. The following spring, they set up the puppet government of Manchukuo and installed Henry Pu-yi, the last of the Manchu dynasty, as its puppet ruler. The Communists continued to fight their way across the country on the so-called "Long March," and by 1936, they had established a strong base in the northwest. In 1937, the Kuomintang formed a united front with the Communists against the Japanese.
In 1937, Japan and China plunged into war. The following year, Japan seized control of most of northeast China, as far inland as Hankou, and the area around Canton on the southeast coast. World War II saw a serious erosion of power for the Kuomintang, while the Communists expanded their membership, military force, and territory. The Kuomintang was split into factions. Severe inflation, official corruption, and loss of morale further weakened the government. Meanwhile, the Communists continued to build strength.
