How many movies have Akiko Yamaguchi and Katsuya Yamada collaborated on?

They have worked on 4 movies together! Their first movie together was Naruto the Movie: Ninja Clash in the Land of Snow (2004) while their highest rated movie together was In This Corner of the World (2016). They have not worked together since In This Corner of the World (2016). They are most known for their animation films together.