Here's a few :

Nagisa Oshima
Shohei Imamura
Kaneto Shindo
Kon Ichikawa
Kenji Mizoguchi
Teinosuke Kinugasa
Yasujiro Ozu
Mikio Naruse
Teinosuke Kinugasa

   Most of these directors films are difficult to find on DVD, though Criterion has one, Good morning, more soon to come of Ozu.  Kon Ichikawa's An Actor's revenge is available across the pond from our friends the Brits.  The rest, I haven't found yet, if you do, please let me know, as I am a BIG fan of Japanese films.  