How many movies have Osamu Okubo and Sumi Shimamoto collaborated on?

They have worked on 5 movies together! Their first movie together was Go! Anpanman: Baikinman's Counterattack (1990) while their highest rated movie together was Go! Anpanman: Tears of the Mermaid Princess (2000). They have not worked together since The Story of the Blue-Eyed Girl (2009). They are most known for their animation films together.