Macgyvercas said:
I've only ever dated whites, but seeing as I want to get a shirt that says "Looking for a Japanese girlfriend" in Japanese and being totally serious while wearing it, that should give you a hint that I don't really care about race as long as the girl is likable.
Then...doesn't this suggest that you DO have a preference, it's just been unfulfilled so far? Actively looking for a girlfriend who is of a particular race over any others, and advertising the fact, IS a preference.
Although, I don't know how much success you would have with that kind of T-shirt. Seems...kind of debasing the act of finding a relationship to an advert which girls can apply to. Could be construed as racist and sexist as well, seen as how you will decide, from the number of girls who "apply", who best fits your interests. This is what you'd do anyway WITHOUT a T-shirt, so why?
I get you wouldn't mean this in a bad way, but you have to think about what other people will assume. It could put people off getting to know you, because a Japanese girl might think you're only into her because she's Japanese, not because she's a nice, interesting person.