How many movies have Naoki Iwasa and Naoto Yamatani collaborated on?

They have worked on 3 movies together! Their first movie together was Lupin the Third: Blood Seal of the Eternal Mermaid (2011) while their highest rated movie together was Lupin the Third vs. Detective Conan: The Movie (2013). They have not worked together since Napping Princess (2017). They are most known for their animation films together.