The term 'China Chief, Once' is referring to Mao Zedong, the former leader of the People's Republic of China. Mao was a revolutionary leader who led the Chinese Communist Party to victory in the Chinese Civil War and established the People's Republic of China in 1949. He served as the Chairman of the Communist Party of China from 1943 until his death in 1976. Mao is often referred to by his three-letter acronym, MAO.