How many movies have Kinji Fukasaku and Tôru Nakajima collaborated on?

They have worked on 9 movies together! Their first movie together was New Battles Without Honor and Humanity 2: Head of the Boss (1975) while their highest rated movie together was Shogun's Samurai (1978). They have not worked together since Gate of Youth (1981). They are most known for their action films together.