Were Japanese immigrants in the pre-Qin period?

Japanese people are descended from pre-Qin immigrants, but they are not only descendants of pre-Qin immigrants. Their ancestors included aborigines, Malays, Koreans and immigrants from China.

When Xu Fudong crossed Japan, he brought many advanced cultures and technologies from China and Qin Dynasty, which had a great influence on backward Japan at that time. The Japanese accepted the sudden advanced culture and technology and applied it for a long time.