How many movies have Ayumi Arai and Naohiro Hirakawa collaborated on?

They have worked on 3 movies together! Their first movie together was Hentai ana nozoki: Kusamura wo kage (2007) while their highest rated movie together was Danrô towairaito (2008). They have not worked together since Mehyô no ori: Ikenie rankô (2009).