How many movies have Hidetoshi Sano and Ikue Otani collaborated on?

They have worked on 4 movies together! Their first movie together was One Piece: The Desert Princess and the Pirates: Adventure in Alabasta (2007) while their highest rated movie together was One Piece Film: Z (2012). They have not worked together since One Piece Film: Z (2012). They are most known for their adventure films together.