Sino-Soviet relations

Sino-Soviet relations (simplified Chinese: 中苏关系; traditional Chinese: 中蘇關係; pinyin: Zhōng-Sū Guānxì; Russian: советско-китайские отношения, sovetsko-kitayskiye otnosheniya), or China–Soviet Union relations, refers to the diplomatic relationship between China (both the Republic of China of 1912–1949 and its successor, the People's Republic of China) and the various forms of Soviet Power which emerged from the Russian Revolution of 1917 to 1991, when the Soviet Union ceased to exist.

In 1921, the Soviet Russia played an important role in supporting the establishment of the Chinese Communist Party (CCP) through the Communist International (Comintern), and decided to support the Kuomintang. The Soviet Union, established in 1922, ordered the CCP to enter into an alliance with the Kuomintang in 1923. The resulting First United Front launched the Northern Expedition, aiming to united China. In 1927, Kuomintang leader Chiang Kai-shek turned against the CCP, leading to the start of the Chinese Civil War; the Soviets offered some aid to the CCP. The Republic of China and the Soviet Union had a brief border conflict in 1929. The Soviet Union also invaded the Chinese province of Xinjiang in 1934, as well as another intervention in 1937 to support the pro-Soviet governor Sheng Shicai. After the beginning of the Second Sino-Japanese War in 1937, the Soviet Union signed a non-aggression pact with China and provided military help. In 1944, the Soviet Union sponsored the Ili Rebellion in Xinjiang. The Soviet Union eventually launched an invasion of Manchuria in 1945, which at the time was under Japanese occupation.

The two countries signed the Sino-Soviet Treaty of Friendship and Alliance, leading to ROC recognition of the Mongolian People's Republic, though the ROC later revoked the treaty. With the resumption of the Chinese Civil War and increasing success of the CCP, the Soviet leader Joseph Stalin decided to aid the CCP against the Kuomintang. CCP leader Mao Zedong proclaimed the People's Republic of China on 1 October 1949, followed by an immediate recognition by the Soviet Union, which emerged as the PRC's closest ally. The two countries signed the Sino-Soviet Treaty of Friendship, Alliance and Mutual Assistance in 1950. The Soviet Union sent significant military and economic aid to the new People's Republic, and the two countries backed North Korea during the Korean War. Relations began to deteriorate under Nikita Khrushchev, with Mao opposing Khrushchev's pursuit of closer relations with the West as well as what Mao called "Soviet revisionism", while Khrushchev opposed Mao's political and economic policies.

The deterioration eventually led to the Sino-Soviet split in 1961. This was followed by a rivalry between the two nations. including fighting in the Sino-Soviet border conflict in 1969 where the Soviet Union considered a preemptive nuclear strike on China; the border conflict led China to not renew its friendship treaty with the Soviet Union. The two countries also competed for the leadership of the international communist movement. The worsening of the relationship led China to improve relations with the United States in the 1970s. After Mao died in 1976, he was succeeded by Deng Xiaoping who initiated the reform and opening up. Though the relationship initially improved, China invaded Soviet ally Vietnam in 1979 after Vietnam had invaded Cambodia to oust the pro-Chinese Khmer Rouge from power. The relationship improved further under the leadership of Mikhail Gorbachev, who took office in 1985 and initiated economic and political reforms in the Soviet Union, with Gorbachev visiting Beijing in 1989 for the first summit between the two nations in since 1959. The Soviet Union dissolved in 1991, leading China to establish diplomatic relations with the Russian Federation.