Chairman of the Communist Party of China
Project 571 () was the numeric codename given to an alleged plot to execute a "coup d'état" against Chinese leader Mao Zedong in 1971 by the supporters of Lin Biao, then Vice-Chairman of the Communist Party of China. In Chinese, the numbers "5-7-1" sound like the term "armed uprising" (). The Chinese government initially claimed that Lin Biao himself had devised Project 571, but evidence inside and outside of China has made it more likely that Lin's son, Lin Liguo, a high-ranking officer in the People's Liberation Army Air Force, instead developed the plot. Any plots that may have been planned or attempted by Lin Biao or his family ultimately failed. Lin's family attempted to flee China for the Soviet Union, but died when their plane crashed over Mongolia on September 13, 1971. A draft copy of the Project 571 Outline was discovered following Lin's death, and was publicly circulated by the Chinese government as a means of explaining the event.