School Wars: Hero (2004)

Original title: スクール・ウォーズ　ＨＥＲＯ　

Set in the mid-1970s, the film is based on the true story of Yoshiharu Yamaguchi, a teacher and former Japanese international rugby union player, who turned-around a failing high school in Kyoto, giving special attention to the rugby team, which included the most disruptive students among its members.