I've prefered girls with dark hair over blondes but not redheads for as long as I remember, even as a young child. I think girls who are Romanian, Hungarian, Bolivian, Moroccan, Vietnamese, Korean, etc. can be exceptionally beautiful. I don't recall when I specifically started liking the way Japanese girls look. It's at least a decade ago.
I also like that Japanese girls have the decency to appear in many pictures and videos, contrary to for example girls from the Middle-East.