Sei Shōnagon, who was born in about 966, was the daughter of Kiyohara Motosuke, one of the compilers of the Gosenshū anthology of waka poetry ("Sei" is the Sinitic reading of the first character used to write "Kiyohara").
After the failure of her first marriage, Sei entered the service of Emperor Ichijō's consort, Teishi (or Sadako), in 993. She was known for her quick wit and sunny disposition, and won a reputation for her familiarity with the Chinese classics, considered an unusual accomplishment for a woman. Her famous rival, Murasaki Shikibu, described her in her diary as a person who liked to show off her knowledge.
After Teishi died, Sei left the palace; virtually nothing is known of the rest of her life. She is usually supposed to have spent her final years in solitude.
It is uncertain precisely when and under what circumstances the Pillow Book came to be written, but according to the most widely accepted theory, a first draft was in existence in about 996, a second draft was produced by about 1000, and a final version followed to which additions were made until 1021 at the latest. The Pillow Book as we have it now is composed of more than three hundred sections of varying length. These sections are generally grouped into three categories on the basis of content:
There are two main textual traditions associated with the Pillow Book. One, the ruisan-bon tradition, attempts to arrange sections of the manuscript in accordance with the above three categories. The other, called the zassan-bon tradition, forgoes any such arrangement. The ruisan-bon tradition is further divided into Sakai-bon and Maeda-bon manuscripts, while the zassan-bon tradition includes Nōin-bon and sankan-bon manuscripts (the first three appellations are based on the names of the manuscript owners, while the last is a descriptive term referring to a three-volume version of the Pillow Book). As a result of this complicated textual background, trying to match up the sections from all the different editions is a frustrating task indeed, and textual variants are numerous.
A number of theories have been proposed for the origin of the distinctive title Pillow Book. All are based on the (possibly apocryphal) "Epilogue," in which Fujiwara no Korechika is said to have given his sister the empress a blank notebook (sōshi) and suggested that she use it as a pillow (makura). The following are the interpretations most often proposed for the meaning of "pillow"; the second and third are the ones regarded as most likely to apply.
In spring, the dawn. The sky gradually brightens against the outline of the mountains, revealing wisps of cloud lightly tinted purple.
In summer, the night. It is of course delightful when the moon is shining, but no less so on dark nights when countless fireflies mingle in flight -- charming indeed when just one or two pass by, emitting their gentle glow. Falling rain, too, is delightful.
In autumn, dusk. As the sun descends toward the ridges of the mountains, the crows wing swiftly back to their nests in groups of three or four or two. Even more delightful is the sight of a line of geese flying far overhead. Then, after the sun has set, the crying of insects and the sound of the wind have a charm that goes beyond words.
In winter, early morning. The delight of falling snow goes without saying, along with the pleasure of pure white frost. Or in the deep cold when there is neither snow nor frost, the hurried stirring of fires and rationing of hot coals seems perfectly suited to the season. As the day wears on and the cold gradually loses its sting, the untended coals in the braziers become disagreeably coated with white ash.