How many movies have Keiichi Sato and Mami Koyama collaborated on?

They have worked on 2 movies together! Their first movie together was City Hunter Special: Goodbye My Sweetheart (1997) while their highest rated movie together was City Hunter Special: The Death of Vicious Criminal Saeba Ryo (1999). They have not worked together since City Hunter Special: The Death of Vicious Criminal Saeba Ryo (1999).