Have a look at this problem with a Japanese font in the graphical Debian installer, which I’ve found via Planet Debian.
Aki understands a bit of Japanese, and some of their former schoolmates *are* half Japanese. I wouldn’t have seen or understood this of course, and not only because I almost never use the *graphical* installer – the old style ncurses one is familiar enough to me.
But thanks to Kentaro Hayashi for fixing this!