Flora on the Sand (1964)

Original title: 砂の上の植物群

One evening, at the Marine Tower observatory, cosmetics salesman Ichiro Iki is drawn into conversation with an unfamiliar young lady Akiko. She invites Ichiro back to a hotel where they make love but part without even exchanging names. A week later, they have a second chance encounter at the observatory. This time, Ichiro is the one who pursues her. Back at the hotel, Akiko begs Ichiro to give her sister – Kyoko, a bar hostess – absolute hell. Akiko resents her sister for lecturing on chastity, while wantonly indulging in promiscuous activity. Ichiro takes an interest in Kyoko and sets out towards her bar…