How many movies have Etsuko Kozakura and Fumitoshi Oizaki collaborated on?

They have worked on 3 movies together! Their first movie together was Sergeant Keroro The Super Duper Movie (2006) and was their highest rated movie together. They have not worked together since Sergeant Keroro The Super Duper Movie 4: Crushing Invasion, Dragon Warriors (2009). They are most known for their animation films together.