How many movies have Kappei Yamaguchi and Ryuji Yoshiike collaborated on?

They have worked on 4 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: Dead End Adventure (2003). They have not worked together since One Piece: The Desert Princess and the Pirates: Adventure in Alabasta (2007). They are most known for their animation films together.