In October 1961 the Chinese Communist Party (CCP) adopted a policy of tacit struggle against the program of the 22nd Congress of the Communist Party of the Soviet Union (CPSU). The CPSU's resumption of de-Stalinization alarmed the Chinese leader, Mao Zedong, but he did not yet want to discard a limited rapprochement with Moscow. However, when high-level Sino-Soviet talks in July 1963 collapsed, the relationship between the CPSU and the CCP became irretrievable. Through the subsequent great polemics, the CCP intended to project itself as the spokesman of true Marxism-Leninism and the natural leader of world Communism. After the CCP attacked the top leaders of the CPSU by name, hostility between the two parties intensified. The breakdown of the CCP-CPSU organizational relationship was only a matter of time. Relying on a large array of Chinese-language sources, including records of Chinese leaders' speeches and comments at secret party meetings, this article reassesses the most critical period in the Sino-Soviet split from October 1961 to July 1964.