How many movies have Ikue Otani and Makoto Sonoda collaborated on?

They have worked on 2 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: Episode of Chopper Plus: Bloom in the Winter, Miracle Cherry Blossom (2008). They have not worked together since One Piece: Episode of Chopper Plus: Bloom in the Winter, Miracle Cherry Blossom (2008).