How many movies have Hiroaki Hirata and Takayuki Gorai collaborated on?

They have worked on 6 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: Strong World (2009). They have not worked together since One Piece: Strong World (2009). They are most known for their adventure films together.