This is the first time I've actually heard anything about this. How accurate was this theory? I've only heard it once, googled it, and then saw it mentioned in a documentary.
Is this just some legend/myth? Or is there actual evidence supporting this theory?
I did a search in Askhistorians, but there wasn't really an answer or any further info.
This theory seems not to be accepted because Hsu Fu's landing was at least nine years away from the introduction of bronze tools, which would signify civilization. Also the type of rice that was prominent in Japan's agricultural development was not from the same area Hsu Fu came from, the Shantung Peninsula.
Source:
Kidder, J. Edward, Jr. "The Earliest Societies in Japan." Cambridge History of Japan. Vol. 1.