Nun in Rope Hell (1984)

団鬼六　修道女縄地獄

aka 団鬼六 修道女縄地獄 · Dan Oniroku: shūdōjo nawa jigoku · Dan Oniroku: Shûdô onna nawa jigoku · Convent Rope Hell · だんおにろく　しゅうどうじょなわじごく

A woman gets caught by the wife of her lover which results in a stabbing. Feeling guilty she runs away and joins a nunnery. But she soon discovers that several nuns and a well known author have turned the place into their own personal S&M playground.