How many movies have Hatsuo Yamaya and Kōji Wakamatsu collaborated on?

They have worked on 19 movies together! Their first movie together was The Embryo Hunts in Secret (1966) while their highest rated movie together was Running in Madness, Dying in Love (1969). They have not worked together since Sosuke Loses His Lover (1992). They are most known for their drama films together.