How many movies have Keiji Fujiwara and Tsutomu Mizushima collaborated on?

They have worked on 5 movies together! Their first movie together was Crayon Shin-chan: Pursuit of the Balls of Darkness (1997) while their highest rated movie together was Crayon Shin-chan: Invoke a Storm! The Kasukabe Boys of the Evening Sun (2004). They have not worked together since The Magnificent Kotobuki (2020). They are most known for their animation films together.