FRien said: According to the wiki, it's Disaster and D.N.A. Softwares who made the music. So unless there's something I missed, that's Rinnosuke's fantheme.
I just checked, and apparently, you're right. I'm still trying to see how a song called "Curious old Shanghai tile" could be Rinnosuke's theme, but at least, ZUN still made a song for this game.