The Sino-Soviet split (1956-1966) was a time when the relations between the People's Republic of China and the Soviet Union weakened during the Cold War. Eventually, China's leader, Mao Zedong, decided to break the alliance with the Soviet Union.
The Soviet leader, Stalin, wanted to help spread communism in the world, including China. In the Second Sino-Japanese War, the Soviets gave weapons and supplies to the Kuomintang, and advised the Communists to ally with them against the Japanese Empire. The Chinese Civil War continued, however. After World War II, Stalin and the Soviet Union helped the Communists. Chinese leaders disliked the Soviet leaders for not helping Mao and the Communists from the start.