How many movies have Iwao Tanaka and Kôichi Imaizumi collaborated on?

They have worked on 4 movies together! Their first movie together was Turtle Vision (1991) while their highest rated movie together was Umagoya no reijô (1991). They have not worked together since (Nama) Tôchô Ripôto: Chiwa (1993). They are most known for their horror films together.