The Key (1965 film)

The Key is a 1965 drama film directed by Yoshishige Yoshida. It is also known by its Japanese title, Kagi. The film is based on the 1956 novel The Key (also known as The Diary of a Mad Old Man) by Jun'ichirō Tanizaki.

The film explores themes of sexual obsession, voyeurism, and the decaying relationship between an aging professor and his younger wife. The professor feigns illness to ignite his wife's passion and keep her interested in him, documenting their intimate lives in a diary which he allows his wife to read, further fueling his voyeuristic desires and manipulating their relationship dynamics. The film is known for its frank depiction of sexuality and its exploration of the darker aspects of human relationships. It stars So Yamamura and Mariko Okada.