tically divided into competing cliques. This political division made it difficult for Chiang to battle the Communists, which the Kuomintang had been warring against since 1927 in the Chinese Civil War. This war continued successfully for the Kuomintang, especially after the Communists retreated in the Long March, until the Xi'an Incident and Japanese aggression forced Chiang to confront Imperial Japan.
The Second Sino-Japanese War (1937–1945), a part of World War II, forced an uneasy alliance between the Kuomintang and the Communists. The Japanese "three-all policy" in northern China—"kill all, burn all and destroy all"—led to numerous war atrocities being committed against the civilian population; in all, as many as 20 million Chinese civilians were killed. An estimated 200,000 Chinese were massacred in the city of Nanjing alone during the Japanese occupation. Japan unconditionally surrendered to China in 1945. Taiwan, including the Pescadores, was put under the administrative control of the Republic of China, which immediately claimed sovereignty. China emerged victorious but war-ravaged and financially drained. The continued distrust between the Kuomintang and the Communists led to the resumption of civil war. In 1947, constitutional rule was established, but because of the ongoing unrest many provisions of the ROC constitution were never implemented in mainland China.
People's Republic of China (1949–present)
Major combat in the Chinese Civil War ended in 1949 with the Communist Party in control of mainland China, and the Kuomintang retreating offshore, reducing the ROC's territory to only Taiwan, Hainan, and their surrounding islands. On 1 October 1949, Mao Zedong proclaimed the People's Republic of China, which was commonly known in the West as "Communist China" or "Red China" during the Cold War. In 1950, the People's Liberation Army succeeded in capturing Hainan from the ROC, occupying Tibet, and defeating the majority of
