Project National Glory (Chinese: 國光計劃) or Project Guoguang was a planned attempt by the Republic of China (ROC), whose government had retreated to Taiwan after losing the Chinese Civil War, to reconquer mainland China from the People's Republic of China (PRC) by large scale amphibious invasion. It was the most elaborate of the ROCs plans or studies to invade the mainland after 1949. Guoguang was initiated in 1961 in response to events involving the PRC, particularly the Great Leap Forward and the Sino-Soviet split. Guoguang was never executed; it required more troops and material than the ROC could muster, and it lacked support from the United States, especially after the Communist developed nuclear weapons and the disastrous naval skirmishes at Dongshan and East Chongwu. The use of a large scale invasion as the initial stage of reunification was effectively abandoned after 1966, although the Guoguang planning organization was not abolished until 1972. The ROC did not abandon the policy of using force for reunification until 1990.