Shinken shobu

In the film, Musashi (Kinnosuke Nakamura), hoping to extend his knowledge of the techniques of personal combat, visits the home of Baiken Shishido (Rentaro Mikuni), a bandit who has developed a highly unorthodox way of fighting with ball and chain in one hand and a small very sharp scythe in the other. Musashi first comes upon Baiken's wife (Hideko Okiyama), also adept in her husband's methods, training her baby not to fear the whirling iron ball or the cries of an advancing warrior. (nytimes.com)