How many movies have Ichirou Ookouchi and Takahiro Sakurai collaborated on?

They have worked on 10 movies together! Their first movie together was Code Geass: Lelouch of the Rebellion Special Edition Black Rebellion (2008) while their highest rated movie together was Berserk: The Golden Age Arc III - The Advent (2013). They have not worked together since Seven Days War (2019). They are most known for their animation films together.