How many movies have Rikiya Koyama and Yukihiko Ichikawa collaborated on?

They have worked on 4 movies together! Their first movie together was Case Closed: The Fist of Blue Sapphire (2019) while their highest rated movie together was Detective Conan: Black Iron Submarine (2023). They have not worked together since Detective Conan: Black Iron Submarine (2023). They are most known for their mystery films together.