There is considerable internationalization work going on in Perl. People like Jeffrey Friedl have been using Perl to process Japanese text for some time, so it is possible even if I haven't done it.

An alternative to consider if you don't want to figure out the appropriate hoops for Perl to jump is Ruby. It was developed in Japan so I bet its support for working with Japanese text is pretty good. I would have to investigate, but I suspect that Perl's Unicode support is further along. But Ruby has natively supported common Japanese formats for a while, but Perl isn't quite so strong there.