I realise it isn't Japan, but the closest place I could find. I was wondering if anyone knows a website (english) with places to train bjj/mma in KwangJu South Korea.... I know it is a longshot, but you never know who lurks on this board.
Good luck with that, I'll put my ear to the ground, but I haven't heard of anything in Kwangju itself. There is almost certainly a kickboxing gym, it also might be worth trying a local hapkido school, though they are a totally mixed bag. A Judo school might also be useful, but again quality does vary and often they do not have many adults as most either have quit or are involved in competetive clubs which usually don't like walk-ons...
I lived and trained in Kwangju, at a place which I don't know the name of. It was near bookucho, if you can find that. I'm sorry it's not much help. They did BJJ, but no proper instruction, just a bunch of guys. Just get a korean to look up UFC, Pride, MMA and kwnagju on google.