Set in during the rise of Japanese militarism, the film follows three students of an elderly karate master, Eiken Shibahara. When their master dies, he leaves behind a single symbolic black belt for the one who most deserves it. The pupils find themselves caught in a clash between their traditional training and the corrupting influence of the Imperial Japanese Army:

Released in 2007, (known in Japan as Kuro-obi ) is a landmark Japanese martial arts drama that stands apart for its brutal realism and rejection of typical "wire-fu" tropes. Directed by Shunichi Nagasaki , the film features legitimate karate experts in lead roles, ensuring that every movement is technically accurate and devoid of special effects. The Story: A Conflict of Ideology

: A pure practitioner who remains faithful to his master’s pacifist teachings, refusing to strike back or use offensive techniques.

: The third pupil who witnesses the diverging paths of his peers as they navigate a landscape of political unrest. Production and Authenticity Black Belt (2007) - IMDb

: His opposite, who believes karate is for destruction. He is easily manipulated by military leaders into using his skills for violent control.