Nyoin (a close female relative of the Emperor or a womwan of comparable standing) (女院)
Nyoin indicates a title bestowed upon a woman, such as the three empresses (grand empress dowager, empress dowager, empress) or an equivalent status (jugo, honorary rank next to the three Empresses and princess, etc.) and is a system that continued from the middle of the Heian period until the Meiji Restoration. "In" means a retired emperor, and "Nyoin" means a woman who gets treated in a similar fashion. Imitating a cloistered emperor, she created In no cho (Retired Emperor's Office), appoint betto (chief officer), hogandai (an administrative official of the Retired-Emperor's Office), shutendai (secretary of the In no tsukasa) and other officers, rule the court, and replenish the Kurodo (Chamberlain).
Object of Imperial Proclamation
Originally, an empress stopped being treated as one (imperial consort) when she became a nun. But during the reign on Emperor Ichijo, in 991, when Empress Dowager FUJIWARA no Senshi was tonsured, she had the good fortune to be given the title of Tosanjoin at the same time as she quit her palace position of empress dowager, and a "Nyoin" was born.
Originally, the title of Nyoin was bestowed only to empresses, especially to those who had become a kokumo (mother of an Emperor); after Princess Shoshi, the daughter of Emperor Gorezei's chugu (second consort), was made Nyoin (Nijoin) in 1074, however, some women received the title simply because of their noble bloodlines, rather than because they had given birth to a child of the emperor.
(However, in the case of Princess Shoshi, some say that she was made Nyoin as a means to open up the empress position so there could be a new empress)
In addition, the system of making an imperial princess an honorary empress (a woman who was not the consort of the emperor but nonetheless held the title of empress) to serve as a foster mother to the emperor began with Imperial Princess Teishi (Ikuhomon-in), daughter of Emperor Shirakawa; this system was later extended to allow "院" (a kanji pronounced "in" that means "imperial court") to be added to the end of the title of an honorary empress by imperial decree, and the system was further extended by Princess Akiko (Hachijo-in) in 1161 to allow "院" to be added to the title of any female member of the imperial family. As a result, use of the Nyoin title, especially for imperial princesses, expanded dramatically, but as a rule it was bestowed on those who were one of empress, emperor's birth mother, or princess; Princess Eikamonin Mizuko (Prince Munetaka's daughter, Emperor Gouda's wife) in 1302, and Kitayamain Yasuko HINO (wife of Yoshimitsu ASHIKAGA) in 1407 were extremely unusual.
From the end of the Heian period into the Kamakura period, influenced by internal strife and ryoto tetsuritsu (alternate accedence from two ancestries of imperial families), there was a flood of use of the Nyoin title, and at one time the number of Nyoin was in the tens. Among these there appeared many princesses who were given a title as a prelude to territorial succession, and some were given the title the same day as they formaly became princess/jugo. The power of the princesses given huge manors was great, and Hachijoin, Senyomonin and Princess Kuniko were examples of those who used wealth to get a look at politics.
Later, from the Muromachi period to the early Edo period, both investiture of the crown ｐrincess and princesses came to an end, as a result of which there was a long period in which only the emperor's birth mother became Nyoin. However, from Emperor Gomizunoo's empress Masako TOKUGAWA (Tofukumonin) Nyoin from an empress was revived, and there were Nyoin from among the princesses, such as Reiseimonin, but it was abolished at the time of the Meiji Restoration, with Naoko OGIMACHI (Shintaikenmonin, Emperor Komei's birth mother) as the last. After that, even though there were calls to revive the Nyoin in regard to the treatment of Yoshiko NAKAYAMA and Naruko YANAGIHARA (birth mothers of Emperor Meiji and Emperor Taisho, respectively), there was a lot of opposition and it did not come to fruition.
Titles
Unlike an ingo (a posthumous title) given to an emperor or retired emperor, the name of a Nyoin (hereafter Nyoingo) was given during her lifetime by Ingo-sadame (imperial decree). Looking at the first two Nyoin, Higashi Sanjoin's title was based on Higashi Sanjo-dono Palace, and Jotomonin's was based on Jotomon-dai (aka Tsuchimikado-dai; another name for Jotomon in Daidairi, the Greater Imperial Palace was "Tuchimikado," and the road that ran through it was called Tsuchimikado Oji or Jotomon Oji), both came from the ridai (palace outside the Imperial enclosure). The next Princess Teishi, the mansions that she inherited were Biwa-dono Palace on Konoe Oji (aka Yomeimon Oji) which runs through Daidairi's Yomei-mon Gate, and Oi-dono on Oi-no-mikado Oji which runs through Daidairi's Ikuho-mon Gate, so her title had a "mon" because of that. However, after Taikenmonin in 1124, it became standard practice for Nyoingo to be given regardless of place of residence.
It is known from records that Nyoingo was chosen from among several proposed candidates, and the decision was based not only on the ridai or monin name, but also whether the characters were good or not or whether it resembles an unlucky predecessor, and it was considered from various angles such as not repeating an existing title. In the case of emperors and retired emperors the same ingo would be used again with "Go" (later) prefixed, but it is notable that Nyoin titles mostly had the prefix "Shin" (new) (Kishi SAIONJI is the only exception); and whereas Nyoingo that repeated ex-emperors' ingo were not used, duplication of Nyoin titles was not considered when deciding an emperor's ingo, as in the case of Emperor Nijo who was preceded by the Nyoingo Nijoin.
The Title of Empress Dowager
One form of Nyoingo was the Mon-ingo that came from Kinri (the Imperial Palace) gates. The first example was FUJIWARA no Shoshi, who was originally named after the ridai, but Jotomonin, who was the mother of the two successive emperors, was cited as a good example; this became the ingo for a majority of all Nyoin. At first it was limited to Kinmon gates (14 gates in the outer wall that encloses Daidairi), but after TAIRA no Shigeko in 1169, palace gates (7 gates in the wall that encloses the outer Dairi), inner gates (12 gates in the inner wall that encloses the middle Dairi) and naikakumon gates, as well as the names of gates of Chodoin (an office at the Heijo-kyo Palace) and Burakuin were used.
Overview of Nyoin