How many movies have Keiko Yamamoto and Shigeru Mizuki collaborated on?

They have worked on 2 movies together! Their first movie together was Spooky Kitaro: The Great Sea Beast (1996) while their highest rated movie together was Spooky Kitaro: Japan Explodes!! (2008). They have not worked together since Spooky Kitaro: Japan Explodes!! (2008).