In Tanizaki’s The Key (Dutch: De sleutel), an elderly couple live somewhat detached lives from each other. Both keep a secret diary. They write about their lives from their perspectives, speculating about the other’s motivations. Both know from each other that the other keeps a diary. They both suspect each other of reading the other’s diary and leave messages in their diaries intended for the other to read. But both write they do not read each other’s diary. But only the reader knows that.

They lead a bizarre sex life with each other, with the man more or less voluntarily drugging the woman, and only in that situation can they genuinely make passionate love. After the man dies (during the act), the woman starts reading his diary (she writes in her diary). She continues her diary, and a bizarre spin ensues, where the truth turns out to be quite different.

The woman’s diary is reminiscent of Sei Shonagon’s The Pillow Book.