How many movies have Hijiri Yamamoto and Kei Machida collaborated on?

They have worked on 4 movies together! Their first movie together was Penguin Highway (2018) while their highest rated movie together was I Want to Eat Your Pancreas (2018). They have not worked together since That Time I Got Reincarnated as a Slime the Movie: Scarlet Bond (2022). They are most known for their animation films together.