From 1912 to 1950 Tibet was under "de jure" suzerainty of the Republic of China; however, the difficulties of establishing a new government in the aftermath of the Xinhai Revolution of 1911, the fractious Warlord Era (1916-1928), the Chinese Civil War (1927-1949) and the overwhelming Japanese invasion and occupation before and during World War II left the Republic unable to exert any effective administration. Other parts of ethno-cultural Tibet (eastern Kham and Amdo) had been under "de jure" administration of the Chinese dynastic government since the mid-18th century; today they are distributed among the provinces of Qinghai, Gansu, Sichuan and Yunnan. (See also: Xikang Province)