Recalling that the Chinese were literate, and the Hakka were not, neither were the Yayoi when they arrived in Japan.
It's somewhat later (8 centuries in fact) before the first Korean speaking Koreans arrived from Korea.
The Hakka, in five migrations, moved from Northern China to Southern China and even today are know as 'the guests'. When they began the migrations in the north, many had Caucasian features and those with those features were killed and persecuted all the way across China.