Saiin (the Priestess or the residence of the Priestess) (斎院)
The name of Saiin was given to a Priestess who served at the Kamo-jinja Shrine from the Heian to the Kamakura period, or at the residence of the Priestess. She was also called Kamo no Saio or Kamo no Saiin.
The origin of Saiin
The origin of the Kamo no Saiin system was traced back to the early Heian period. When Emperor Heizei had a conflict with his brother, Emperor Saga, and tried to move the capital in Heian kyo back to Heijo kyo, Emperor Saga petitioned the deity that he would dedicate his daughter to Kamo no Okami (a guardian god of the capital) as 'Areotome' (a woman to join in the ceremony held at the Kamo-jinja Shrine for welcoming gods) if he had a chance of winning. After Emperor Saga's side won as a result of the Kusuko Incident in 810, Emperor Saga dedicated his daughter Imperial Princess Uchiko as Saio, as he had pledged; that is probably the beginning of Kamo no Saiin.
The Saiin Priestess system
Following the Saio (Saigu) of the Ise-jingu Shrine, the successive Saio Priestesses were selected from princesses of blood or female relatives of the Emperor (the Imperial Family).
After two years of purification in Shosaiin (the residence of Saiin in the Imperial Court), the Saiin Priestess entered into Honin (the official residence of Saiin) located in Murasakino on the north side of Heian kyo early in April during the third year of her term. (According to Bunei TSUNODA's theory, the original site of the residence of Saiin was located near present-day Ichiitani nanano yashiro in Kamigyo Ward, Kyoto City.)
The Priestess stayed there to lead a pure life avoiding Buddhist services and impurity, and joined in religious rites held at Kamo-jinja Shrine or in the official residence of Saiin. The Kamo Festival on the Day of the Cock in April was especially important, the Saio Priestess underwent a purification ceremony, and then visited both the Kamo Wakeikazuchi-jinja and Kamo Mioya-jinja Shrines to perform religious rites. The Saiin procession on that occasion was so magnificent and attractive that Sei Shonagon wrote the proceedings of the festival in her book, "Makura no soshi" (The Pillow Book), and Murasaki Shikibu also described it in the famous scene of the Carriage Incident in the chapter about 'Aoi' in the "Tale of Genji."
While both the Ise no Saigu and the Kamo no Saiin systems coexisted, Saiin near the capital was regarded more important than Ise no Saigu located far from the capital; successive Saiin Priestesses were rarely selected from female relatives of the Emperor, and most of their real mothers were highborn ladies. Meanwhile, Saiin Priestesses were not always dismissed when the Emperor abdicated the throne, and there were many examples of Saiin Priestesses remaining in office through more than two Emperor regimes. Among them, Imperial Princess Senshi was called "Dai Saiin" (Great Saiin Priestess) because she actually had the longest tenure of Saiin over 5 emperors of fifty-six years (from the times of Emperor Enyu to Emperor Goichijo). In addition, after being dismissed, most Saiin Priestesses remained unmarried throughout life as was the case for the Saigu Priestesses; however, a few of them married the Emperor or nobles, and several Nyoin (wives of the former Emperors or princesses who could receive the same treatment with Cloistered Emperors) were produced during the rule of a cloistered emperor.
Saiin and literature
During the mid-Heian period, Saiin constantly became the center for the court culture functioning as an artistic place where tanka poets or the nobles got together. Many successive Saiin Priestesses were well known for literary works: the first Saio Priestess, Imperial Princess Uchiko, who was a distinguished composer of Chinese style poetry; the Great Saiin Priestess, Imperial Princess Senshi, whose name appeared in "The Pillow Book" and "The Murasaki Shikibu Diary"; the Rokujo Saiin, Imperial Princess Baishi, who held many tanka poetry contests; and Imperial Princess Shikishi, who became an accomplished poet of the Shin Kokinwakashu (the New Collection of Ancient and Modern Japanese Poetry). According to one tradition, FUJIWARA no Shoshi ordered Murasaki Shikibu to write a new interesting story Imperial Princess Shikishi had asked for; that was the birth of "The Tale of Genji." The deep cultural relationship between Saiin and the Imperial Court (especially "Kokyu" - the inner palace reserved for women) can be found in "The Pillow Book" in a scene where Imperial Princess Senshi and FUJIWARA no Teishi exchange letters.
It is also particularly noteworthy that Hikaru Genji's cousin, Asagao no Saiin, who appears in "The Tale of Genji," is set up as a Saiin Priestess from a female relative of the Emperor, actually rare in the case of Saiin. Saiin and Saigu Priestesses, or princesses who were former Saiin or Saigu Priestesses often appear in "The Tale of Sagoromo," which may suggest that this book was probably written by Rokujo Saiin no Senji, a court lady serving Imperial Princess Baishi.
The end of the Saiin
Although Saiin became part of the flourishing court culture, it was often discontinued during the late Heian period due to the Taira-Minamoto War. After Imperial Princess Reishi was dismissed, the Saiin Priestess system completely ended due to the turmoil during the Jokyu Disturbance or lack of finance in the Imperial Household, and was not restored until recently. In addition, 'Saio dai,' which has now acquired wide popularity during the Aoi Festival, literally means the representative of the Saio or the Saiin Priestess, and recalls the good old days of the Kamo Festival.