Чрезмерно зрелая грудь / Uresugita chibusa: hitozuma (1973)

This softcore pinku eiga melodrama from Nikkatsu in-house luminary Chusei Sone concerns a married woman (Junko Miyashita) whose husband’s infidelity drives her to sleep with both of her sisters’ lovers. Kazuko Shirakawa, in one of her final appearances before her highly publicized wedding, plays the combative mistress who convinces the heroine that her marriage has come to an end.