During my research, found this blog and linked to a couple of sites that currently accept bitcoin or monacoin, just thought i'd share. Of course use chrome and translate to english if needed. Now i don't know how much volume it gets, but it is proof for some real use in Japan:
Online shopping malls:
I also read somewhere a guy a long time ago buying a house in Japan with this coin.
gotta credit the blogsource i got this info from: