I guess you can get a Japanese girl if you are so-called a WASP and have
so-so looks.
I don't know whether it was true or not, and what the current situation is like ,
but a rumor used to take air on the internet that Japanese girls were called " nikubenki 肉便器” which means whoever can get in bed with them as long as you are a white guy.
I think that's partly because most of them have been obsessed with Western culture,
partly because in Japanese society, there is not such a steady religious background as Christianilty that morality with regard to sexual relations has gradually changed After the War.