How many movies have Kōji Wakamatsu and Yoshiaki Ohtani collaborated on?

They have worked on 5 movies together! Their first movie together was Blood of Lust Is Dripping (1965) while their highest rated movie together was The Embryo Hunts in Secret (1966). They have not worked together since The Embryo Hunts in Secret (1966). They are most known for their drama films together.