Imperial Princess Toshi (当子内親王)

Imperial Princess Toshi (Masako) (1001 - October 16, 1022) was the first princess of Japan's 67th Emperor Sanjo. Her mother was the empress consort FUJIWARA no Seishi, the daughter of FUJIWARA no Naritoki. She was Saigu (an Imperial Princess appointed to serve the deities of Ise-jingu Shrine). Her maternal half-brothers included Imperial Prince Atsuakira and Priestly Imperial Prince Shoshin.

In 1011, her father, Emperor Sanjo, ascended to the throne and she became an Imperial Princess by the Imperial proclamation. In 1012, she was appointed to Saigu by divination. She entered Shosaiin (Hall of Initial Abstinence) in August 1013 and in September of the same year, she entered Nonomiya-jinja Shrine. In 1014, she went down to Ise Province. She resigned from the position of Saigu in February 1016 in the wake of the Emperor Sanjo's abdication and returned to Kyoto in October of the same year. She entered into the Buddhist priesthood in 1017. She died in 1023. The age of her death was 22.

At the ceremony of 'Wakare no Migushi' which was held when Imperial Princess Toshi, who had been appointed to Saigu by divination, was about to depart for Ise Province, her father, Emperor Sanjo, made her look back at him because of the pain of parting, although neither the Emperor nor she was allowed to do so (according to "Okagami" - the Great Mirror). Although she was loved by the Emperor as deeply as mentioned above, the rumor that FUJIWARA no Michimasa committed adultery with Imperial Princess Toshi was spread in 1016 when she came back from Ise to Kyoto. Emperor Sanjo, who was infuriated at the above rumor, censured Michimasa and purged Menoto no Chujo Naishi (a court noble lady) who mediated between them in spite of the efforts of the Empress consort and imperial princes to calm him down. Thereafter, the Imperial Princess was taken care of by her mother Seishi and her relationship with Michimasa was severed.
People in general felt sympathy for her, saying 'Aside from Saigu of Ise Monogatari (The Tale of Ise), this Imperial Princess has already resigned as Saigu.'
However, the Imperial Princess entered into the Buddhist priesthood in sorrow and ended her short life six years later. Incidentally, Michimasa's waka poem 'Now that things have come to this pass, I believe I have no choice but to give you up. I wish I could inform you of my determination directly, not through someone else. I wish I could meet you at least once more,' which he presented after he was alienated from the Imperial Princess (compiled in "Goshui wakashu" - Later gleanings of Japanese poems), was later selected as one of Hyakunin Isshu (Hundred poems by one hundred poets).