Withered Tree, the Adventures of Monjiro 1972

Kogarashi Monjiro is a lone samurai who agrees to take responsibility for a murder that his friend committed so that he can stay with his dying mother, with the expectation that his friend will confess and get him pardoned once she dies. Monjiro is sentenced to an island for prisoners. When he discovers that his friend's mother has died over a year ago, Monjiro seeks to escape with a group of prisoners in order to get his revenge.