Looking to train in Japan

Hello! I was wondering if anyone could give me information on how to go about training martial arts in japan? Not necessarily working there, but more like intensive training. There's a website called bookmartialarts.com that helps students find temples all over china / thailand / etc where they could go and live for anywhere from a month to 2 or 3 years, studying six days a week, several hours a day, where the room and board is included in the training price. That website has nothing for japan, though, so i was hoping maybe someone on here would be able to suggest the equivalent? It's more of an exchange student situation than a regular dojo, if that makes sense.

How good is your Japanese?
What you will need to do is locate a dojo and apply as a student. Aside from that there are a couple short term package type trips in Okinawa that are the most popular.

I have no japanese at all! I'm looking for longer term, rather than a week or two. Like i said, i can find a ton in china / thailand / etc but nothing for karate in japan! My friend will be there for a few weeks starting tuesday (he travels back and forth quite a bit,) and said he'd try and find me a sponsor. Essentially i'm looking for a place that would accept work for board and training (if they do that there.) It's common in western europe, but i don't know about the asian cultures.

You can only work if you have a work visa. Exchanging work for board is considered paid work, and is illegal without a work visa. A hostel in Hokkaido recently came under fire for this.

You can ask somebody who can understand Japanese to translate the containts.
http://www.budo.or.jp/bosyu.html