How many movies have Fumihiko Tachiki and Shin-ichiro Shirakura collaborated on?

They have worked on 2 movies together! Their first movie together was OOO, Den-O, All Riders: Let's Go Kamen Riders (2011) while their highest rated movie together was Kamen Rider: Beyond Generations (2021). They have not worked together since Kamen Rider: Beyond Generations (2021).