The Key is a 1983 Italian film directed by Tinto Brass. It is adapted from the eponymous novel by Japanese author Jun’ichirō Tanizaki.
Set in Venice during the fascist era, an elderly English professor, who is the director of the Biennale d’Arte, and his young wife Teresa, managing a boarding house in the city’s heart, seek to explore their sexual relationship’s “self.” One day, the husband deliberately leaves the key on his studio floor, which unlocks the drawer hiding his diary filled with lascivious fantasies.
Accidentally, Teresa discovers the key, unlocks the drawer, and reads the diary. This compels her to maintain her diary, where she confesses her amorous passion and the deceitful acts carried out with Laszlo, her daughter Lisa’s young Hungarian fiancé. A peculiar and perverse dialogue unfolds between the couple through their diaries, establishing a sexual understanding owing to these mutual confessions. Amid yet another sexual escapade they had grown accustomed to, the professor suffers a stroke, rendering him nearly paralyzed.
The narrative concludes with the professor’s demise, indirectly triggered by his daughter, who knowingly reads to her dying father the raunchy diary pages about Teresa’s affairs with her fiancé Laszlo. The professor’s funeral, conducted on a gondola, coincides with Mussolini announcing Italy’s entry into the war on June 10, 1940, from Palazzo Venezia’s balcony in Rome.
Stefania Sandrelli recounts that the costume fitting occurred in a lingerie shop, Treppiedi in Rome. The actress fully undressed and paraded naked for Brass and his wife.
The Key marked a significant commercial triumph for Brass. In Italy, the film emerged as the highest-grossing Italian movie and the second-highest grossing film overall for the 1983-84 cinema season, trailing only behind Flashdance.