I don’t know about legality, but most forms online in Japan accept 4 characters at most for family name; the vast majority of people have two characters with one and three being less common. Okinawa, I think has the highest instance of 4-character surnames, but I may be wrong on that.
I don’t know about legality, but most forms online in Japan accept 4 characters at most for family name; the vast majority of people have two characters with one and three being less common. Okinawa, I think has the highest instance of 4-character surnames, but I may be wrong on that.