How many movies have Akihiro Kokubun and Shōji Sakai collaborated on?

They have worked on 4 movies together! Their first movie together was Groper Train: Wet Commuter (1991) while their highest rated movie together was (Nama) Tôchô Ripôto: Chiwa (1993). They have not worked together since (Nama) Tôchô Ripôto: Chiwa (1993).