How many movies have Yasumasa Koyama and Yoshikazu Iwanami collaborated on?

They have worked on 19 movies together! Their first movie together was YuruYuri Nachuyachumi! (2014) while their highest rated movie together was Girls und Panzer das Finale: Part IV (2023). They have not worked together since Girls und Panzer das Finale: Part IV (2023). They are most known for their animation films together.