Both claim that they want to keep their notes secret from another, and complain about the difficulties in their sex life: she about her husband's inability to satisfy her, he about her insatiability, mixed with her oldfashioned attitude and rejection of his erotic preferences.

At the same time, he has his doctor inject him hormones to improve his potency, which result in dangerously high blood pressure and memory defects.

In her last entries, Ikuko reveals that both she and her husband wrote their diaries in full knowledge that the other side reads them, that her states of unconsciousness were at times faked, and that Toshiko possibly made arrangements so that her mother and Kimura could meet.

[4] In his book Five Modern Japanese Novelists, author Donald Keene states that The Key gained attraction and was widely discussed for its explicit eroticism.

Yet, although formally "brilliantly handled", the novel is missing typical Tanizaki themes like the longing for a mother or worshipping of a cruel woman, concluding that it was, compared to others of the writer's works, "not very deeply rooted".