The Key

About The Key on 123movies: released in 1974, directed by Tatsumi Kumashiro, running 90 minutes, produced in Japan. A college professor wants to bring the joys of sex to his frigid wife. He convinces his son in law to sleep with her because the idea arouses him, while also making him insanely jealous. The professor keeps a journal of his fantasies in a locked cupboard and hopes that his wife will find the key and read it.