>>18
Then you should be using <span lang="ja">. Or, if the font itself is important, and not just any random font that the user has set up in their browser (e.g. if you're dealing with SJIS art, which I suspect is what you're referring to), <span style="japanese"> along with a .japanese { font-family: Mona, "MS PGothic" }..

Next fake reason to use non-Unicode fonts?