In the past 2000 years, China conquered Central Asia, Afghanistan, and SE Asia. But China never waged a single invasion on India until 1962. Invading the land of Buddha was considered a sin. Communism destroyed traditional foreign relations between India & its eastern neighbors. There is one exception to this rule. In 648, a Chinese ambassador who had been attacked by Indian king Arunasa recruited Nepali soldiers and defeated him. But even in this case, the encounter took place between surrogates, and there was no direct Chinese Indian conflict.