It probably depends on your distro too. Even if your fonts are not Japanese, you probably have a lot of true type fonts already on your computer. Why don't you do a quick find for them?
Code:
find / -name "*ttf"
In debian they are on /usr/share/fonts/...
But I think you can put them somewhere on your home dir so that only you can access them. If it's your computer, just put them on the global dir just to save you the trouble. You can put any font file over there and you'll be able to use them since the next time you start X. If you use gnome, Ctrl-L fonts:// on nautilus should show you your current fonts.