How many movies have Ichirô Kojima and Kinji Fukasaku collaborated on?

They have worked on 4 movies together! Their first movie together was Drifting Detective: Tragedy in the Red Valley (1961) while their highest rated movie together was Drifting Detective: Black Wind in Harbor (1961). They have not worked together since Man with a Funky Hat: The 20,000,000 Yen Arm (1961). They are most known for their action films together.