How many movies have Naoko Matsui and Yukiko Akiyama collaborated on?

They have worked on 4 movies together! Their first movie together was Case Closed: Countdown to Heaven (2001) while their highest rated movie together was Detective Conan: The Phantom of Baker Street (2002). They have not worked together since Detective Conan: Magician of the Silver Sky (2004). They are most known for their mystery films together.