Chiang Kai-shek was an influential member of the nationalist party Kuomintang (KMT) and Sun Yat-sen's close ally. He became the Commandant of Kuomintang's Whampoa Military Academy and took Sun's place in the party when the latter died in 1925. In 1928, Chiang led the Northern Expedition to unify the country, becoming China's overall leader. He served as chairman of the National Military Council of the Nationalist Government of the Republic of China (ROC) from 1928 to 1948. Chiang led China in the Second Sino-Japanese War, during which the Nationalist Government's power severely weakened, but his prominence grew. Chiang's Nationalists engaged in a long standing civil war with the Chinese Communist Party (CCP). After the Japanese surrender in 1945, Chiang attempted to eradicate the Communists. Ultimately, with support from the Soviet Union, the CCP defeated the Nationalists, forcing the Nationalist government to retreat to Taiwan. Long (Lung) Yun (simplified Chinese: ?お; traditional Chinese: 纒冻; pinyin: L?ng Y?n; WadeGiles: Lung Yun) (November 27, 1884 - June 27, 1962) was governor and warlord of the Chinese province of Yunnan from 1927 to October 1945, when during the 'Kunming Incident' he was overthrown in a coup by Du Yuming on the orders of Chiang Kai-shek.