claim: Project Y was a movie.
evidence: The Sino-Soviet split -LRB- 1960 -- 89 -RRB- was the deterioration of political and ideological relations between the neighboring states of the People 's Republic of China -LRB- PRC -RRB- and the Union of Soviet Socialist Republics -LRB- USSR -RRB- during the Cold War .. Union of Soviet Socialist Republics. Soviet Union. Cold War. Cold War. In the 1960s , China and the Soviet Union were the two largest communist states in the world .. The doctrinal divergence derived from Chinese and Soviet national interests , and from the governments ' different interpretations of Marxism -- Leninism .. doctrinal. doctrine. In the 1950s and the 1960s , ideological debate between the communist parties of the USSR and China also concerned the possibility of peaceful coexistence with the capitalist West .. peaceful coexistence. peaceful coexistence. capitalist. Capitalism. Yet , to the Chinese public , Mao Zedong proposed a belligerent attitude towards capitalist countries , an initial rejection of peaceful coexistence , which he perceived as Marxist revisionism from the Soviet Union .. peaceful coexistence. peaceful coexistence. capitalist. Capitalism. Mao Zedong. Mao Zedong. Marxist revisionism. Marxist revisionism. Furthermore , since 1956 -LRB- when Nikita Khrushchev denounced the legacy of Stalin -RRB- , China and the USSR had progressively diverged about Marxist ideology , and , by 1961 , when the doctrinal differences proved intractable , the Communist Party of China formally denounced the Soviet variety of communism as a product of `` Revisionist Traitors '' .. doctrinal. doctrine. Nikita Khrushchev. Nikita Khrushchev. Stalin. Stalin. Communist Party of China. Communist Party of China. communism. communism. The split concerned the leadership of world communism .. communism. communism. world communism. world communism. The USSR had a network of communist parties it supported ; China now created its own rival network to battle it out for local control of the left in numerous countries .. Lorenz M. Luthi argues  :. The Sino-Soviet split was one of the key events of the Cold War , equal in importance to the construction of the Berlin Wall , the Cuban Missile Crisis , the Second Vietnam War , and Sino-American rapprochement .. Cold War. Cold War. The split helped to determine the framework of the Second Cold War in general , and influenced the course of the Second Vietnam War in particular .. Cold War. Cold War. The divide fractured the international communist movement at the time and opened the way for the warming of relations between the United States and China under Richard Nixon and Mao in 1971 .. warming of relations between the United States and China. China–United States relations#Rapprochement. Richard Nixon. Richard Nixon. Relations between China and the Soviet Union remained tense until the visit of Soviet leader Mikhail Gorbachev to Beijing in 1989 .. Mikhail Gorbachev. Mikhail Gorbachev. The split was primarily caused because of two main factors  : differing national interests and various interpretations of communist ideology .