How were the Japanese formed?

Best Answer: The Japanese Islands were formed, and continue to form at a convergent plate boundary with a significant subduction zone. In fact, it's the Pacific plate being subducted beneath the North American plate. Yes, Japan is on the North American plate. read more

The subducting plates, being deeper than the Eurasian plate, pulled parts of Japan which become modern Chūgoku region and Kyushu eastward, opening the Sea of Japan (simultaneously with the Sea of Okhotsk) around 15-20 million years ago, with likely freshwater lake state before the sea has rushed in. Around 16 million years ago, in Miocene period, a peninsula attached to the eastern coast of the Eurasian continent was well formed. read more