The Japanese are considered today to be descended from a mixture of the ancient hunter-gatherer Jōmon culture and the later rice agriculture Yayoi culture.

These two major ancestral groups come to Japan over different routes at different times.

The Jōmon ancestors are an Ice Age culture that may have come to the Northern and Southern Japanese archipelago around 20,000 BCE, when there is an ice bridge connecting Siberia and Northern Japan.Mark J. Hudson, Professor of Anthropology at Nishikyushu University, Kanzaki, Saga, Japan, said Japan was settled by a "Proto-Mongoloid" population in the "Pleistocene" who became the "Jōmon" and their features can be seen in the "Ainu" and "Okinawan" people.

(Hudson, Mark J.

(1999).

Ruins of identity: ethnogenesis in the Japanese Islands).

The Jomon share many physical characteristics with Caucasians, but Brace says that they are a separate genetic stock and have affinity with the old mongoloid (Proto-Mongoloid) (Lost World: Rewriting Prehistory— How New Science Is Tracing America's Ice Age Mariners.

New York: Atria Books.

Madsen, DB, ed)