How many movies have Tsutomu Mizushima and Yasumasa Koyama collaborated on?

They have worked on 6 movies together! Their first movie together was Girls und Panzer: The Movie (2015) 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.