How many movies have Shizuo Kurahashi and Yasutoshi Niwa collaborated on?

They have worked on 6 movies together! Their first movie together was Sakura Wars: The Movie (2001) while their highest rated movie together was The Garden of Sinners: Paradox Spiral (2008). They have not worked together since The Garden of Sinners: Future Gospel (2013). They are most known for their animation films together.