When I started reading your post at the first then I thought its all about the Japan being the legal country of all who is supporting the crypto currency as whole. But later when I read your second post then everything got cleared up. Lolz.

Well, I am not sure there is any easy way to know or sort out if they are from the Japan or not as you will always have to read the whitepaper or at least their social networks to know from where the project is. I would say start searching all the project with their Twitter, as the location is always mentioned on the homepage. I cant help wit direct names as I dont know really any of them.