I don't want to pretend as though I have a good answer for you, since I'm not familiar with racial dynamics within Japanese society.

But, if I was taking an educated guess, I'd say that someone who is both visibly Black and Asian in their features would probably encounter more racism in Japan than a person who was Japanese-presenting in appearance. In fact, I think a person who was White or Latine might also encounter racism within Japanese society. Now, how much and in what forms -- I don't have any data from Japan to provide you with a more solid assessment.