How many movies have So Hayakawa and Taketoshi Watari collaborated on?

They have worked on 4 movies together! Their first movie together was Seifuku shojo: Za ejiki (1986) while their highest rated movie together was Gimme Shelter (1986). They have not worked together since Shimai renzoku reipu: Eguru! (1989). They are most known for their horror films together.