Recent versions of operating systems should display Japanese characters without additional configuration. The following sample displays fine on Linux (tested: Firefox, Konqueror) and Windows XP (tested: Firefox, IE):
If you’re using IE8, you may have to click on the “Compatibility Mode” button to display the kanji characters; hiragana and katakana display fine without it. (MS’s handling of “compatibility” in IE is a rant for another day.)
If the sample above still doesn’t look right, you may need to install some additional fonts.
For basic information on installing Japanese fonts, see Help:Installing Japanese character sets on Wikipedia.
For Linux, use your software package manager to browse for Japanese fonts. Package names may vary from distribution to distribution.
Under Fedora, for example, “yum install fonts-japanese” should be sufficient.
Microsoft provides ClearType fonts; just Google for “Japanese ClearType fonts for Windows”. The package for XP may have been replaced with a “Vista”-tagged title, but it is also for XP.
Note: extracted from Introduction