How many movies have Hiroshi Katsuno and Kōsei Saitō collaborated on?

They have worked on 4 movies together! Their first movie together was G.I. Samurai (1979) while their highest rated movie together was Onihei Crime Files: Bungoro Amabiki (2009). They have not worked together since Onihei Crime Files: Sutegoro Takahagi (2010).