How many movies have Kazuhiko Inoue and Nobuhiro Otsuka collaborated on?

They have worked on 4 movies together! Their first movie together was Naruto Shippuden the Movie: The Will of Fire (2009) while their highest rated movie together was Natsume's Book of Friends: Ephemeral Bond (2018). They have not worked together since Natsume's Book of Friends: Ephemeral Bond (2018). They are most known for their animation films together.