How many movies have Akira Kasahara and Ryusei Nakao collaborated on?

They have worked on 5 movies together! Their first movie together was Go! Anpanman: The Shining Star's Tear (1989) while their highest rated movie together was Go! Anpanman: Tears of the Mermaid Princess (2000). They have not worked together since Go! Anpanman: Gomira's Star (2001). They are most known for their animation films together.