Naked Rashomon, Showa onnamichi: Rashomon, 昭和おんなみち 裸性門 (1972) dir. Chûsei Sone

A nobleman with a barren wife finds a mistress who is fertile and able to give him the heir he desperately wants. When his mistress gives birth to twins (a boy and a girl). The nobleman orders his bodyguard to kill his mistress and her infant daughter. The bodyguard is unable to bring himself to commit murder and he helps the nobleman s mistress and her infant daughter find a new life. Flash forward nineteen years, the daughter the nobleman never wanted and thought was dead reemerges and falls in love with the nobleman s son (her brother).