?In 1971 China and India were allies against US imperialism. Pakistan was supported by the US in 1971.
Did you know that during 1971's war US asked China to escalate? But China knew that India had fortified it's borders and was actually prepared unlike 1962. Soviets too under our treaty of friendship built up troops on China's borders to discourage China from participating in the war.
Then the rest is history how Soviets sent nuclear subs to discourage American and British warships from meddling in the war.
In the following years Nixon visited China and the relationship blossomed, China developed as quickly as it did due to that historic visit and later movement of Western industries to China for cheap manufacturing.