Shintaro Katsu
The first three films, directed by Kenji Misumi, were released in 1972 and produced by Shintaro Katsu, Tomisaburo Wakayama's brother and the star of the 26 part "Zatoichi" film series. The next three films were produced by Wakayama himself and directed by Buichi Saito, Kenji Misumi and Yoshiyuki Kuroda, released in 1972, 1973, and 1974 respectively.