The document summarizes the key reasons why the Chinese Communist Party (CCP) defeated the Kuomintang (KMT) party in the Chinese Civil War from 1945-1949. When World War 2 ended in 1945, the CCP already controlled much of rural China while the KMT was confined to Sichuan province. Despite initial US support for Chiang Kai-shek and the KMT, by adopting guerrilla warfare tactics and gradually shifting to conventional battles, the CCP's military forces (PLA) were able to seize the initiative, capture key cities and territories, and ultimately force the KMT to retreat to Taiwan by 1949, allowing Mao Zedong to establish control of mainland China.