"Shinagon" refers to the four court nobles (MINAMOTO no Toshikata, FUJIWARA no Kinto, FUJIWARA no Tadanobu, and FUJIWARA no Yukinari) who were active in the era of Emperor Ichijo in the middle Heian Period. The name, Shinagon (four nagons), derived from the fact that FUJIWARA no Tadanobu was Dainagon (chief councilor of state) and the other three served as Gon Dainagon (provisional chief councilor of state).
Kakugon Kandachime' (warrior nobility of Third Rank or higher)
It is said that the word 'Shinagon' was derived from "Jukkinsho" (A Miscellany of Ten Maxims - Chapter 1: Shinagon), and was patterned after a wise man of the Liu Bang era of Han China, called "Shiko" ("Shiki," the Lord Liu Genealogy). According to "Zoku Honcho-ojo-den," in addition to these four there were originally another five (FUJIWARA no Sanesuke, MINAMOTO no Sukeyoshi, TAIRA no Korenaka, FUJIWARA no Arikuni, and one other), and they were collectively called "Kugyo" (nine nobles).
On the other hand, the Shinagon were the court nobles who actively supported the government of FUJIWARA no Michinaga.
In a July 23, 1005, article in "Shouki," a diary written by FUJIWARA no Sanesuke - who kept a certain distance with Michinaga - there is a description as follows:
Kakugon' means a lower-ranked retainer (samurai) who serves for a high-ranking official, dedicating himself to his duties, and this comment can be interpreted to mean that Sanesuke was ridiculing, saying that Saemon no kami (captain of the Left Division of Outer Palace Guards) FUJIWARA no Tadanobu, and other Kandachimes (court nobles, including Toshikata, Kinto, Yukinari in this context) had been reduced to mere retainers of the Safu (left ministry, meaning minister of the left FUJIWARA no Michinaga). And the reason why Sanesuke, although called 'Kenjin Ufu' (Wise Right Ministry), was not included in Shinagon, was that he was in a position that might threaten the power and influence of Michinaga, because Sanesuke was a person of wisdom with a vast knowledge of Yusoku kojitsu (court and samurai rules of ceremony and etiquettes) and, moreover, a legitimate son of the Ononomiya family line.
MINAMOTO no Toshikata was a son of MINAMOTO no Takaakira, who fell from his position in the Anna Incident, and the heir to the book of rituals "Saiguki" written by Takaakira. Because of his father's downfall, Toshikata's Joshaku (peerage) was at age of 17, delayed relative to other court nobles who were conferred peerage at an average age of 15. However, with the marriage of his younger sister MINAMOTO no Akiko to Michinaga, he gained a kinship relation with the Sessho/Kanpaku (regent and chief adviser to the Emperor) family, and he took charge of raising political funds for Michinaga, working as an intermediary between Michinaga and other nobles and officials by making use of his kinship connection, although his promotion to Gon Dainagon took place when he was 59 years old - far from rapid advancement. FUJIWARA Sanesuke criticized Toshikata, writing "he is notorious for his avarice and conspiracy" (article on September 2, 1011, of "Shouki"). Toshikata's name was not included among the Court Council members present at a fierce debate between Fujiwara Sanesuke and Shinagon when faced with the Toi invasion in 1019, because he had already submitted his Johyo (letter of resignation) from the position of Gon Dainagon (which was accepted in November 1019), and he was therefore not invited. Afterwards, when Toshikata found out about that incident, he conveyed his clear-cut opinion to FUJIWARA Sanesuke (article on October 29, 1019 of "Shouki").
According to the story of "Okagami" (The Great Mirror), FUJIWARA no Kinto was known as a person with whom FUJIWARA no Michinaga had a strong rivalry in his childhood, however, in reality, he often worked with Michinaga in such cases as Dairi Utaawase (the palace poetry contest) on July 24, 986, in which he was selected and participated together with Michinaga and Tadanobu as a representative of the young nobles. At the same time, as a son of Kanpaku (chief adviser to the Emperor) FUJIWARA no Yoritada, his future was deemed promising; he was promoted to Shogoinoge (Senior Fifth Rank, Lower Grade), an unusually high rank for his age, on March 9, 980, at his coming of age celebration in the Imperial Palace, and a crown was put on his head by Emperor Enyu, according to "Nihongi Ryaku" (Summary of Japanese chronologies) and "Fuso Ryakki" (A brief History of Japan), although in the latter, this event was erroneously compiled in Sannenjo (the article in the year 980) of "Fusoki". In reality, he was the only one of the Shinagon who became a member of the Imperial Court before FUJIWARA no Michinaga came to power in September, 992. He was also good at waka (Japanese poetry), Chinese-style poetry, and music with string instruments, and he was well known as author of "Wakan Roei Shu" (Collection of Japanese and Chinese poems) and "Hokuzansho "(Manual of court and samurai rules of ceremony and etiquette), among others. Afterwards, unlike his cousin Sanesuke, he came to agree with Michinaga on political issues, in the face of the emergence of the Kujo line coupled with the downfall of Ononomiya line, and strengthened ties with Michinaga by taking his son FUJIWARA no Norimichi as his son-in-law. However, in 1017, he was overtaken by Tadanobu in promotion, and the death of his daughter around same time caused him to decide to become a priest. In "Eiga Monogatari" (A Tale of Flowering Fortunes, vol. 27) there is a scene in which Michinaga, who had already taken vows, presented a priestly robe to Kinto. As a result, he lived the longest of all of the Shinagon.
FUJIWARA no Tadanobu was a son of Dajo-daijin (Grand minister of state) FUJIWARA no Tamemitsu and a cousin of Michinaga. As described before, in the Utaawase held in 986, when he was invited to participate with Michinaga and Kinto, he was one year younger than them, and the youngest of all the invited participants. From November 986, he served one year as Sakone no shosho (Minor Captain of the Left Division of Inner Palace Guards) together with Michinaga. While he was Kurodo no to (Head Chamberlain), Kanpaku FUJIWARA no Michitaka became seriously ill, and this provoked a disturbance in relation with nairan-senshi (a preliminary inspection of imperial decree) for Michitaka's son, FUJIWARA no Korechika. It is supposed that among the Shinagon, Tadanobu was closest to Michinaga, and he also accompanied Michinaga, who had already entered the priesthood, when he went to Arima-Onsen Hot Spring for medical treatment and recuperation in 1024. In addition, he was appointed to be Chugu-daibu (Master of the Consort's household) to Michinaga's two daughters, FUJIWARA no Shoshi and FUJIWARA no Ishi, and then to Togu-daifu (Lord Steward) to Imperial Prince Atsuhira (later Emperor Goichijo), who was a son of Michinaga's, that is, his grandchild. In 1020, he was promoted to Dainagon, as the only person who attained this post among Shinagon, and the next year, when FUJIWARA Sanesuke was appointed to Udaijin (Minister of the Right), he was the only Dainagon with the senior rank. Afterwards, longing for the ministerial post that was only one step away, Tadanobu frequently prayed for it. For this, Fujiwara Sanesuke, who won the post over Tadanobu, expressed his discomfort in his diary "Shouki." However, Tadanobu never became a minister, in contrast to FUJIWARA no Yorimichi and his brother Norimichi, who became ministers when they were still young, and Sanesuke, who enjoyed exceptional longevity for that time.
FUJIWARA no Yukinari was a grandchild of Sessho (regent) FUJIWARA no Koretada, but he lost his grandfather and father in his infancy and was brought up by his maternal grandfather. Later, he became famous as one of the three famous calligraphers, and at the same time was know as an excellent official, and served actively as the closest adviser to the Emperor. He worked in the post of Kurodo no to (Head Chamberlain) to the Emperor for 6 years, and then became Keishi betto (administrator of household affairs) to the first Imperial Prince Atsuyasu when the prince was three years old, as the prince lost his real mother FUJIWARA no Teishi one year before. On the other hand, he confessed in his diary "Gonki" that under the instruction of Michinaga, he pressured Emperor Ichijo to carry out the following two arrangements. One was to set up the practice of 'two empresses for one emperor,' by backing up the daughter of Michinaga, Shoshi, to be a wife of Emperor Ichijo, although the emperor already had a wife, Empress Teishi, and the other was to set up the second Imperial Prince Atsunari (later Emperor Goichijo), who was a grandchild (a son of his daughter) of Michinaga as the next Togu (Crown Prince), in spite of the fact that there was already an Imperial Prince Atsuyasu. He also earned Michinaga's trust to the point that when Michinaga became seriously ill, he called Yukinari to ask him to be Koken (guardian) of his legitimate son Tsuru gimi (Yorimichi）. On the other hand, Emperor Ichijo also kept Yukinari close, even on his deathbed, and it was also Yukinari that protected Imperial Prince Atsuyasu, who was excluded from succession to the throne, until the prince's sudden death at the age of 20, while serving as Betto (chief officer) for the Imperial Prince family. However, on official matters, he sometimes opposed the aggressive policies of Michinaga. Although Yukinari won Michinaga's trust, their personal relationship seems to have been a little bit distant in comparison with that between Michinaga and the other three. FUJIWARA no Nagaie, Yukinari's daughter, was married to Michinaga's son, but she died early, and then Nagaie took Tadanobu's daughter as his wife, but she also died at a young age. After that, when Yukinari tried to marry off another daughter to Nagaie, Michinaga refused her, and when Michinaga tried to match his son with Sanesuke's daughter, FUJIWARA no Chifuru, his son, Nagaie, refused her, and as a result neither of the two marriages happened.
End of the 'Shinagon' era.
In 1019, the same year that FUJIWARA no Michinaga entered the priesthood, MINAMOTO no Toshikata retired from his official post, so did FUJIWARA no Kinto in 1024 consequently and Kinto became a priest two years later. In June 1027 Toshikata died, and in 1028, FUJIWARA no Michinaga and FUJIWARA no Yukinari both died on January 9. In 1035, FUJIWARA no Tadanobu, who never gave up hope of becoming minister, died, and lastly Kinto died in 1041 (even after Kinto's death, it was five years more before the minister's seat, for which Tadanobu had been longing in life, became finally available).