The Japanese like Africans, placing them only slightly lower than Europeans. Basically if you're not dressed like a thug and don't have certain tattoos, and aren't Brazilian, Korean or Chinese, you'll usually be treated pretty nicely.
IN 1990, Japan allowed entry of Brazilians of Japanese descent up to the 3rd generation, and many Brazilians went to Japan to work as cheap labor since Brazil's economic situation was pretty bad.
Like all "migrant workers", they're considered low class and are treated that way, similar to how Turkish people are treated in Germany.