The Japanese are funny buggers. The whole nation loves S&M. They are the Germans of Asia, functional, autocratic, correct.
I've had a Japanese boyfriend, sex with quite a few Japanese and also it's not uncommon here in NZ to see Japanese rent boys, or to be able to pull Japanese rent boys off the net here. The Japanese can get work permits to stay in NZ for 12 months. Quite a few ex-rent boys come here to get away from their former lives and to start over and re-inevnt themselves.
One thing I can say is that they are almost always fucking HOT in the sack! And generally they seem to like doing it with white, and black guys, so if I was you I'd just contact them anyway until you find one who's English is good enough that you can communicate with them. The site that lonelywomabt mentioned is a really good one as well as you can chat to other gai jing living in Japan and get some info from them on how to proceed. I would do that if I were you.
Don't expect the Japanese to be str8 up with you. They would never be that impolite. It almost amounts to lying from our perspective, but a Japanese person will quite happily leave you with the impression they are quite happy with something, or are quite willing to do something, when nothing could be further from the truth. They just don't want to be impolite by saying so in case it should cause you offense. Drives me nuts.
JESUS LOVES YOU, yes, even you nancies