How many movies have Kazuhiro Koyama and Mari Mashiba collaborated on?

They have worked on 3 movies together! Their first movie together was Crayon Shin-chan: Honeymoon Hurricane ~The Lost Hiroshi~ (2019) while their highest rated movie together was Crayon Shin-chan: Shrouded in Mystery! The Flowers of Tenkazu Academy (2021). They have not worked together since Crayon Shin-chan the Movie: The Tornado Legend of Ninja Mononoke (2022). They are most known for their animation films together.