How many movies have Kenji Hattori and Takehito Koyasu collaborated on?

They have worked on 4 movies together! Their first movie together was Mobile Suit Gundam F91 (1991) while their highest rated movie together was Ranma ½: The Movie — The Battle of Nekonron: The Fight to Break the Rules! (1991). They have not worked together since The Mystical Laws (2012). They are most known for their animation films together.