If it's a thread started about a bass artist and his music, it goes in the Bass Zone. If we eventually have enough interest for a separate section for bass artists, we can do that.
If it's not about bass, like your Japanese band thread, then it's off-topic for bass, and that's exactly what the Outpost Cafe is for.
One thing we don't want is to have a bunch of subsections that many members never visit. I've noticed that happening even at some large forums. That's why we'll wait and gauge interest as we grow.