The Sino-Soviet split was a geopolitical and ideological rift between the People's Republic of China (PRC) and the Union of Soviet Socialist Republics (USSR) that occurred in the late 1950s and early 1960s. The split was caused by a combination of political, economic, and personal differences, as well as ideological differences between the two communist nations.

One major source of tension was the USSR's perception that the PRC was becoming too independent and not sufficiently following the Soviet model of socialism. The USSR also resented China's attempts to spread its own version of communism to other countries in the socialist bloc, which the USSR saw as a challenge to its own leadership.

Additionally, there were economic and territorial disputes between the two countries. The USSR had been providing economic and military aid to China during the Korean War, but after the war, they expected China to repay the aid with raw materials and technology. China, however, saw the aid as a gift and felt no obligation to repay it.

The situation was further exacerbated by the personal relations between the leaders of the two countries. Soviet leader Nikita Khrushchev and Chinese leader Mao Zedong had different ideologies and visions for the future of communism. Mao saw Khrushchev as too focused on peaceful coexistence with the West and not sufficiently committed to world revolution.

The split was formalized in the early 1960s, when the USSR withdrew its advisors from China, and China began to pursue a more independent foreign policy. The two countries also began to support opposing sides in various conflicts around the world.

The Sino-Soviet split had a major impact on the communist world and the global balance of power. It led to a realignment of alliances and the emergence of China as a major player in international affairs. It also had a profound effect on the development of communism in China, leading to the emergence of a distinct Chinese brand of communism that continues to shape the country's politics and society to this day.