should be helpful in answering your question. It doesn't necessarily cover every release of the film but DVD-Basen (and the DVDBeaver link you'll find there) is generally a good place to start. DVDCompare.net is also another useful site (but perhaps not in this particular case). As for "The Hidden Blade", there is also a R3 Hong Kong version, a Thai version, a R4 Australian release, and probably quite a number of European releases that are not currently listed with reviews at DVDBasen.
Since you've watched "The Hidden Blade", I'm assuming you've watched "The Twilight Samurai". If you haven't, then most certainly seek it out. They are both fine films but "The Twilight Samurai" is superior.