Sino-Soivet Split.

[Bostana]

This is when Mao announced Khrushchev was a revisionist. But there is more to it then that. I would be greatfull if someone can give me more info on this subject.
Peace.

[Sixiang]

Tensions were already existent between the Soviet Union and the PRC before the official split.

First of all, the Soviet Union sent aids to the young Chinese Communist Party in the 1920's and advised them on working in the urban areas of China with the small industrial working class in those locations. The CPSU at that time considered China to be still in the feudal stage of development. For this reason, it gave funds, arms, and training to the nationalist government, party, and army, the Guomingdong (GMD also sometimes called by its Cantonese named KMT). The CPSU advised the CCP to form a united front with the GMD so as to bring about a "People's Democracy" to China to bring capitalism to China so socialism could then come. The CCP and GMD did form a united front in 1922-1927 to take care of the warlord problem in China. See, after the Qing empire disbanded, China was divided and left in shambles. There were multiple governments across the country and also many warlords who would control regions and fight for more power and personal wealth and generally just ravage the peasants. The CCP and GMD wanted to unite China again into a single nation and then get to economic development. So the CCP ended up joining the GMD, which was originally led by a famous guy named Sun Zhongshan (Cantonese name: Sun Yat-Sen), who is considered the kind of father of both Chinese governments even today. He was succeeded in leadership of the GMD by a Soviet-trained military commander named Jiang Jieshi (Cantonese: Chiang Kai-Shek). Jiang hated communists and wanted them gone from the united government. So, he had them purged in 1927 from Chinese cities in the "Shanghai Massacre." It was in this famous event that the Communists were symbolically and literally purged from the united front, government, and cities.

They had to relocate to the countryside. The Soviet advisers to the CCP were criticized and largely removed from top ranks. It was in 1927 that Mao first advised that the party embrace the peasantry as a revolutionary force that the communists should lead (not just the industrial proletariat). This was a major split with Soviet ideology already. And the Soviet Union was funding the GMD largely during this period because it saw it as the party that would practically lead to capitalism in China.

The Japanese invaded China in 1931 and both parties fought them, however, the GMD was trying to kill of the communists at the same time despite the CCP wanting to form a second united front to defeat the Japanese. It wasn't until 1937, when a GMD general kidnapped Jiang Jieshi and forced him to align with the communists to form the second united front to fight the Japanese. The Soviet Union funded this united front and trained personnel. After the Japanese left in 1945, civil war resumed in full scale in 1946. Stalin was supportive of the Communists this time because the U.S. was supportive of the GMD (although the U.S., too, funded both parties in their fight against Japan).

In 1949, the nationalists and 2,000,000 people fled the mainland to Taiwan, where that government still resides. The Soviet Union was allied with the PRC from that point on until 1960. There were some minor tensions and problems between then leading up to this. First of all, China was upset with the Soviet Union for giving the Korean communists the go-ahead to invade the U.S.-occupied south in 1950 because China was not consulted or alerted of this until fighting already began. China and the Soviet Union still both funded the Korean communists and China sent a lot of troops to Korea to help them fight off the U.S. forces.

When Khrushchev took over the CPSU and condemned Stalin for collectivization and the personality cult and attempted to "de-Stalinize", Mao was critical of him, but not entirely yet. It wasn't until 1960 that tensions had reached a climax and both parties called each other revisionist and the Soviet Union pulled out all Soviet personnel from China. See, there were Soviet engineers and technicians who had blueprints for how to run factories, which Chinese had little experience with. These advisers were key in helping China develop efficiently productive factories early on. They took their blueprints with them.

The Soviet Union and PRC had border conflicts and small skirmishes resulted in the late 60's. The USSR also sided with India in the 1962 Sino-Indian War. They did, however, both fund Vietnam in the war against America.

Mao's major criticisms of Khrushchev were his attacks on Stalin, opening up relations with Yugoslavia again, and the "peaceful coexistence" idea. That last thing is that Khrushchev downplayed the inevitable war between capitalist and socialist countries and said that the two can exist in the world peacefully, giving support to reformism in capitalist countries for communist parties. Mao was vehemently against this. You can't have communism unless you directly challenge the capitalists and get rid of capitalism across the globe. Mao believed in constant revolutionary class struggle to bring about communism.

That's my attempt at an explanation in a nutshell.