How many movies have Sonny Chiba and Takanori Oya acted in together?

They have worked on 6 movies together! Their first movie together was Battles Without Honor and Humanity: Deadly Fight in Hiroshima (1973) while their highest rated movie together was The Decisive Power of Aikido (1975). They have not worked together since Japan's Don (1977). They are most known for their action films together.