How many movies have Gōzō Sōma and Koji Ota collaborated on?

They have worked on 4 movies together! Their first movie together was Invasion of the Neptune Men (1961) while their highest rated movie together was Japan Organized Crime Boss (1969). They have not worked together since Yakuza Wolf 2: Extend My Condolences (1972). They are most known for their action films together.