Don't know where you read that satoshi is from Japan?even if he has a Japanese's origin , he could be living in the USA right now.
Edit : removed links of images (it didn't appear rapidly)
That could be, of course, but I've always suspected that Satoshi isn't one person but a group, and probably associated with one of the American alphabet agencies, like the CIA--and I'm not even a conspiracy theorist. When he wrote posts here his English was impeccable. That doesn't rule out being Japanese, but I doubt he would be a native of Japan.
I just don't know and I've stopped wondering. Bitcoin has become bigger than the founder, and his disappearance was smart on his part--if it's a he and I don't know that it is.