It is thought that the Jinshin War in 672 led to Ise Jingu becoming a shrine for the protection of the nation in ancient Japan. This war, the largest in ancient times, was fought to decide the next emperor. When Emperor Tenmu won the war and ascended to the throne, he attributed his to the divine protection received from the deity Amaterasu-Omikami. Since then, Ise Jingu, which venerates this deity, has had the status of a guardian shrine for the state. Princess Oku, a daughter of Emperor Tenmu, served Ise Jingu. A strip of wood with writing on it (mokkan) mentioning her name was found at an archeological site in the old capital of Asuka (in the central part of present-day Nara Prefecture), and it provides evidence to confirm her existence as the oldest Saio. She is also famous for her poem dedicated to the memory of her late younger brother, who had been murdered on suspicion of treason, published in the Man’yoshu, the oldest collection of Japanese poems.
Princess Inoue, a daughter of Emperor Shomu, was a Saio in the 8th century. Her father is well known for having Todai-ji Temple’s Great Buddha built in Nara, and for his great devotion to both deities and buddhas, which resulted in accelerated development of the Saiku system on his initiative during his daughter’s period of service. After retiring as the Saio and returning to the imperial capital, Princess Inoue married a male member of the Imperial family. Because her husband later ascended to the throne, she became an empress, the only one to do so among all former Saio. However, caught up in a political conflict, she was forced to abdicate from her status as empress on suspicion of attempting to murder her husband using a curse, and died a mysterious death along with her son, a prince. Incidentally, both her daughter and granddaughter were later selected as Saio.
Princess Masako was a Saio in the 10th century, and a daughter of Emperor Daigo, one of the representative emperors of the Heian period (late 8th to 12th centuries). She was appointed as Saio when her brother by a different mother ascended the throne. However, she had been in a romantic relationship with a man since before her appointment as Saio. Because her status as Saio required her to remain unmarried, they ended their relationship. Her lover, the famous poet Fujiwara no Atsutada, later published a collection of poems, which shows sorrowful exchanges of poems between the lovers. Nevertheless, after retiring as the Saio and returning to the imperial capital, Princess Masako instead married Fujiwara no Morosuke, a promising aristocrat and a cousin of her ex-lover, Atsutada. At that time, very few princesses who had served as Saio got married.
Princess Masako was a favorite subject for historical stories written in the 11th century. Her father, Emperor Sanjo, suffered political oppression by Fujiwara no Michinaga, a powerful figure at that time. As a Saio in such an era, she attempted to support her father by conveying divine oracles from the deity at Ise Jingu that she had obtained in her dreams. After retiring as the Saio and returning to the imperial capital, she fell in love with an aristocrat named Fujiwara no Michimasa. It is said, however, that she shaved her head herself and entered a convent, because she incurred the wrath of her father, the former emperor. A poem composed by her lover, Michimasa, was published in the Hyakunin Isshu, a 13th-century anthology of excellent Japanese waka poems.
Princess Yoshiko was a Saio in the 11th century, and was distantly related to the emperor through her father, a cousin of the emperor’s father. During her nearly 20 years of service as the Saio, at a festival event at Ise Jingu in 1031, she condemned some powerful figures of that time for disrespecting Ise Jingu and accused the chief officer of the Saikuryo of committing many injustices, claiming these statements to be divine oracles. This was the first time for a Saio to convey oracles, which were disseminated to the imperial capital, and it resulted in political turmoil. Exhibition Hall II displays an illustration depicting her conveying oracles.
Princess Nagako served as Saio while her father was on the throne, following Princess Yoshiko. She was appointed while she was a child as a response to the turmoil triggered by the oracles conveyed by Princess Yoshiko. Various historical records about her remain including one record of the Saio’s journey of six days and five nights from the imperial capital to Ise. This was used as the basis for the Saio Gunko (The Saio Procession) video at the museum. The historical records also include details about the cultural activities at the Saiku, such as kaiawase, a competition between two teams comparing the excellence of the waka poems they compose.
Princess Yasuko was a Saio in the 13th century, and the last Saio who came to the Saiku. The Genpei War in the late 12th century, involving the whole nation in civil strife, forced the Saio system to be temporarily suspended. Although the system was resumed later, some emperors did not appoint a Saio immediately after they ascended the throne, or did not send a Saio to the Saiku. After Princess Yasuko retired as a Saio and returned to the imperial capital in 1272, no Saio were sent to the Saiku, even though some Saio were appointed.
In 1333, Emperor Go-Daigo attempted to defeat the samurai regime based in Kamakura and establish a system of direct imperial rule. He decided to restore the Saio system as a symbol of his imperial rule and send a Saio to the Saiku. The appointment of Princess Sachiko, his daughter by his most loved empress, suggests Emperor Go-Daigo’s great expectations for the Saio system. However, his new regime collapsed in only three years, and Princess Sachiko left the temporary Saio palace that was located in a suburb of the imperial capital. After this time, emperors lost political power, and no further Saio were selected again.