Marc Gravell announced the new support for Kanji tags a couple weeks back, but it looks like it may have gone unnoticed.
You are one of the first site that's getting this feature, so there may be some bugs lurking around. If you run into any issues either with the Kanji tags or with the plain old English tags, please let us know right away. You can post any issues you find in this thread.
Other language sites tend to use their native language tags as primary and set up synonyms in English, but you could go either way - up to and including not using non-English tags at all.
Still, we'd love some feedback on how these are working or whether you've chosen not to use them.
Thanks and enjoy!