Forum Moderators: coopster
MySQL -National Character Sets and Unicode [mysql.com]
that looks like the proper chapter.
I think there would be no problem storing the characters and pulling them out. I perceive the problem comes in using any sort/search features of mySQL as Japanese characters sets are double bytes. So one Japanese character will look like this ¤Î in your database and on the web page.
I would also think that there would be easy ways to program around this by using unique ids, dates, etc to control your data.