How many movies have Hajime Oikawa and Kow Otani collaborated on?

They have worked on 5 movies together! Their first movie together was All's Quiet on the Recruit Front (1991) while their highest rated movie together was Gamera 2: Attack of Legion (1996). They have not worked together since Gamera 3: Revenge of Iris (1999). They are most known for their science fiction films together.