How many movies have Etsuji Yamada and Rei Sakuma collaborated on?

They have worked on 4 movies together! Their first movie together was Fair, then Partly Piggy (1988) while their highest rated movie together was Go! Anpanman: The Pyramid of the Rainbow (1997). They have not worked together since Go! Anpanman: The Pyramid of the Rainbow (1997). They are most known for their animation films together.