Nice job. I run the only English language LARP in Japan, and also have the first and only LARP gear shop (brick and mortar) in Japan. We use Epic Armoury weapons, or similar realistic looking weapons.
Our LARP is part of the Underworld LARP from Canada. Its a horror-medieval fantasy LARP with a very developed core rule book. There are chapters throughout Canada and a development of a few chapters in the US, and of course us in Japan.
I randomly stumbled across a couple of papers about LARPing in Japan a few months ago. This isn't you, is it?
The Power of Just 100 Yen: LARP in Japan
I've heard of underworld although we don't have a local group. Glad to see that the culture has spread overseas.
Belegarth has also had some luck with globalization - in addition to the massive number of US groups there are a handful of Canadian (that's me!) and Mexican groups. There's also single groups that exist (or used to exist) in Italy, Germany, Denmark, China, Australia, Puerto Rico, Hawaii, and probably a few others I'm not aware of. It really only takes one dedicated player to bring an activity to a new community :)
That article was written by a friend, and member of my LARP group, Bjorn Ole Kamm.
Nice to hear about your group. Its best to have a group who works on rule books, and the mechanics of the game. I like to play, and don't want to get bogged down in the rules.