Hi, Lowry. I had the same problem with my xt720, and I found the solution.
In two words, you must find and download DroidSansJapanese.ttf file and copy it to your system directory /system/fonts. Sounds simple, but in order to have write access to /system/fonts directory, you must have root access. I managed to do this with Universal Androot application (to gain root-access), and Root Explorer app (to copy file, can be found on Market).
Universal Androot can be downloaded from here: [APP] [ROOT] 1-click root for N1 (Latest ver: 1.6.2 beta 5) - xda-developers