How many movies have Keiko Ichihara and Naoko Matsui collaborated on?

They have worked on 9 movies together! Their first movie together was Detective Conan: Magician of the Silver Sky (2004) while their highest rated movie together was Detective Conan: The Raven Chaser (2009). They have not worked together since Detective Conan: The Eleventh Striker (2012). They are most known for their animation films together.