The Chinese Communist Revolution started from 1946, after the end of Second Sino-Japanese War, and was the second part of the Chinese Civil War. It was the culmination of the Chinese Communist Party's drive to power after its founding in 1921. In the Chinese media, this period is known as the War of Liberation (simplified Chinese: 解放战争; traditional Chinese: 解放戰爭; pinyin: Jiěfàng Zhànzhēng).
The Communist Party of China was founded in 1921. After a period of slow growth the Communists fell victim in 1927 to a purge by their chief political rival, the Kuomintang or Chinese Nationalist Party led by Chiang Kai-shek. After 1927, the Communists built up local bases throughout the country and continued to hold them until the Long March. During the Japanese invasion and occupation, the Communists built more bases in the Japanese occupied zones and relied on them as headquarters.
The Nationalists had an advantage in both troops and weapons, controlled a much larger territory and population, and enjoyed broad international support. The communists were well established in the north and northwest. The best trained Nationalist troops had been lost in early battles against the better equipped Japanese army and in Burma, while the communists had suffered less severe losses. The Soviet Union, though distrustful, provided aid to the communists, and the United States assisted the Nationalists with hundreds of millions of dollars' worth of military supplies, as well as airlifting Nationalist troops from central China to Manchuria, an area Chiang Kai-shek saw as strategically vital to retake. Chiang determined to confront the PLA in Manchuria and committed his troops in one decisive battle in the autumn of 1948. The strength of Nationalist troops in July 1946 was 4.3 million, of which 2.2 million were well-trained and ready for country-wide mobile combat.
On October 1, 1949, Mao Zedong proclaimed the establishment of the People's Republic of China. Chiang Kai-shek, 600,000 Nationalist troops, and about two million Nationalist-sympathizer refugees retreated to the island of Taiwan. After that, resistance to the Communists on the mainland was substantial but scattered, such as in the far south. An attempt to take the Nationalist-controlled island of Kinmen was thwarted in the Battle of Kuningtou. In December 1949 Chiang proclaimed Taipei, Taiwan the temporary capital of the Republic, and continued to assert his government as the sole legitimate authority of all China, while the PRC government continued to call for the unification of all China. The last direct fighting between Nationalist and Communist forces ended with the communist capture of Hainan Island in May 1950, though shelling and guerrilla raids continued for a number of years. In June 1950, the outbreak of the Korean War led the American government to place the United States Seventh Fleet in the Taiwan Strait to prevent either side from attacking the other.