How many movies have Shinji Watanabe and Toshiaki Tsushima collaborated on?

They have worked on 2 movies together! Their first movie together was Onihei Crime Files Special: Okatsu from Yamabukiya (2005) while their highest rated movie together was Onihei Crime Files: The Inside Woman (2008). They have not worked together since Onihei Crime Files: The Inside Woman (2008).