The Erotomaniac Daimyo (1972)

Kiyohime, a daughter of Tokugawa Ienari is married-off to Tadateru Ogura, the lord of a Kyushu clan. However, the lord's sexual inexperience and Kiyohime's strict morals lead to significant crisis in their marriage. To improve his sexual prowess, the lord is introduced to Sandra, a French woman held captive by usurer-smuggler Hatakaya. This results in the lord's choosing Sandra as his mistress. Kiyohime's attendants see this move as an insult and have Sandra beaten and imprisoned. Nevertheless, Sandra escapes with the help of Morita, a retainer of the lord. Out of bitterness and as some sort of revenge, the lord imposes a sex ban on his subjects.