Within The Black

Has anyone here ever heard about this?

I only just now heard about it. I was watching a video that mentioned it briefly and now it has me thinking. According to the Graduate University for Advanced Studies in Japan, many people who are Japanese living in Japan may not be Japanese at all, but rather Korean. I guess a lot of workers moved to Japan post-WWII as well as in the early 1900's after the conquest of Korea. Wouldn't it be interesting if a good chunk of people in Japan are not actually Japanese at all?

Many people living in the United States are not Americans, they are Europeans. In fact, the United States is a territory formed by settlers. Even the Australians are not true Australians, they were the British sent to Australia as a punishment.
We live in a mixed-race world, every country in the world is formed by settlers, not just the Japanese.