How many movies have Koichi Yamadera and Mari Okada collaborated on?

They have worked on 3 movies together! Their first movie together was Zorori the Naughty Hero: Quest For The Mysterious Treasure (2006) while their highest rated movie together was Zorori the Naughty Hero: Heroes of Space (2015). They have not worked together since A Whisker Away (2020). They are most known for their animation films together.