The first Japanese arrived via Korea - there're probably a few waves.Plotinus said:Yes, blindside - basically the early history of Japan is extremely obscure, but I understand that it's thought that what would later become the Japanese state first emerged in around 300 (perhaps slightly earlier than I suggested). It's a time shrouded in myth and legend, from which practically no records survive. So quite when the Japanese actually arrived there isn't really known, but they certainly weren't the dominant power on the archipelago for some time.
I know that some of the earliest Japanese courtly aristocrats were actually Korean. Korea proved to a great transmitter to Japan.
The earliest 'tributary' mission fr Japan was recorded during the period immediately after the late Han IIRC (3-4th century CE). There're some dispute over where this 'Japanese' entity was actually located... i.e. whether on Kyushu island or in the Honshu Kansai region...