How many movies have Mami Koyama and Michihiko Suwa collaborated on?

They have worked on 6 movies together! Their first movie together was City Hunter: .357 Magnum (1989) while their highest rated movie together was Detective Conan: Episode One - The Great Detective Turned Small (2016). They have not worked together since City Hunter: Shinjuku Private Eyes (2019). They are most known for their animation films together.