The Chinese race is actually a political creation of the Han dynasty, in which they are still known as Han Chinese today.

Before Han there was the tyrannic Qin dynasty, China's first imperial dynasty. There were 2 groups that escaped Qin, one to Japan and another down south to unknown whereabout (presumably Vietnam)

Based on the Han racial unification, Japanese are actually quite 'far', the closest cousins for the Chinese people are the North Vietnamese and North Koreans.