Here are my Japanese faves (all are available from amazon.com; amazon.co.uk and ebay.com).
Kinji Fukasaku (the King) : "Japan organized crime boss", "Sympathy for the underdog", "Street mobster", "Yakuza papers" (all 5 of them), "Graveyard of honor" (not ot be mixed with Miike's boring remake), "Yakuza graveyard", "Shogun's samurai", "New battle without honor and humanity", sure "Battle royale 1"
Meiko Kaji (this lady is something) : "Female convict Scorpion" series (3 parts by Shunya Ito), "Lady Snowblood".
Junko Fuji (cool woman too) : "Lady yakuza 1-3"
Seijun Suzuki : "Tokyo drifter", "Branded to kill"
Norifumi Suzuki : "School of holy beast"

The best (INHO) sites on Japanese cinema
www.10kbullets.com
www.midnighteye.com
www.supertoni.ch
And look at this
http://www.panikhouse.com/movies/sukeban/index.html

Can't wait, seems interesting.