How many movies have Ikue Otani and Kohei Tanaka collaborated on?

They have worked on 10 movies together! Their first movie together was One Piece: Chopper's Kingdom on the Island of Strange Animals (2002) while their highest rated movie together was One Piece: Stampede (2019). They have not worked together since One Piece: Stampede (2019). They are most known for their animation films together.