How many movies have Seiji Takaiwa and Toshihiko Sahashi collaborated on?

They have worked on 8 movies together! Their first movie together was Kamen Rider Den-O The Movie: I’m Born! (2007) while their highest rated movie together was Kamen Rider Den-O & Kiva: Climax Deka (2008). They have not worked together since Heisei Rider vs. Showa Rider: Kamen Rider Wars feat. Super Sentai (2014). They are most known for their adventure films together.