There are belly dance instructors all over the world actually-here is a list of some dance instructors in Japan:
http://www.orientaldancer.net/belly-...ructors/japan/
There are a lot of good instructors that have videos out. One that I personally recommend is the 3 part beginning teaching series by Ruby Jazayre. It is a set of 3 dvds, one for posturing/warm up, one for upper body, and one for lower body. It is very, very good.
You can get it from her site at
www.rubyjazayre.com.