So, I end up in Japan a fair amount for work, but have yet to dive anywhere there. (Usually because I'm either by myself or with people who aren't certified...) Not sure when I'll be back -- next year hopefully -- but while I'm stuck in the states, I thought I'd research (=dream about) where I can go next time I'm there.

So my question: Where are the best spots between Tokyo and Hiroshima, and are there any good shops I can check out to find a good dive master? (Japanese speaking is fine, though English is preferred.)