Whom did the two factions of the Communist Party support, after its split in 1964 and why?

In coalition parties, the differences in ideologies remain within the party and fight each other without leaving the party. These groups are known as factions. In such a way leaders would not join opposition parties and the integrity of the party would be maintained on the outer fronts. In 1964, the Communist Party faced a major split into the Communist Party of India and the Communist Party of India – Marxist. These groups supported different ideologies which intensified all the more at the time of Sino-Indian war. The factions within the party came to be known as the leftists and the rightists. The leftists supported the pro-Chinese and on the other hand the rightists supported the Soviet Union.