How many movies have Koji Eto and Takashi Takeuchi collaborated on?

They have worked on 10 movies together! Their first movie together was The Garden of Sinners: A Study in Murder (Part 1) (2007) while their highest rated movie together was The Garden of Sinners: Paradox Spiral (2008). They have not worked together since Fate/stay night: Heaven's Feel III. Spring Song (2020). They are most known for their animation films together.