How many movies have Ken'ichirou Katsura and Koichi Yamadera collaborated on?

They have worked on 1 movie together! Their first movie together was Ranma ½: The Movie 2 — The Battle of Togenkyo: Rescue the Brides! (1992) and was their highest rated movie together. They have not worked together since Ranma ½: The Movie 2 — The Battle of Togenkyo: Rescue the Brides! (1992).