Same issue on Windows 7, not only for Japanese but all the characters not included in the font you choose are displaying in boxes. There are some exceptions: any fonts that have been defined a key (key value can be even left blank) with in `HKEY_LOCAL_MACHINE/Software/Microsoft/Windows NT/Current Version/FontLink/SystemLink`, CJK characters could display although the fallback CJK fonts are not what I specified (the value I assigned to the key). Maybe you could try to create a fontlink key in registry to at least let the characters show up first.