Imperial Princess Yasuko (康子内親王)
Imperial Princess Yasuko (her given name can be also pronounced as "Koshi") (919 - 957) is considered to have been the 4th wife of FUJIWRA no Morosuke, who was a member of the Imperial family during the Heian period. She was ranked as Ippon (First Order of an Imperial Prince) and Jusango (honorary rank next to the three Empresses: Great Empress Dowager, Empress Dowager, and Empress).
Her father was Emperor Daigo (Yasuko was the sixteenth daughter), and her mother was Empress FUJIWRA no Onshi. Her elder maternal brother was Imperial Prince Yasuakira, and younger maternal brothers were Emperor Suzaku and Emperor Murakami.
Brief Personal History
Imperial Princess Yasuko who was born when her mother, Onshi, was thirty five years old, and was younger than her eldest brother by sixteen years, received warm hospitalities as a younger sister of the Crown Prince. She was given a folding screen made by Ono no Tofu at the time of Mogi (ceremony for girls on reaching womanhood) in 933, and the folding screen is famous for waka (a traditional Japanese poem of thirty-one syllables) composed by MINAMOTO no Kintada. However, she had no opportunities to get married thereafter, and lived in the Kokiden (one of the Heian Palace buildings) which was her mother's residence and became called Shoyosa later. At the age of thirty five, she was ranked Jusango.
However, she got married to FUJIWARA no Morosuke in the same year. An Imperial princess, who was an elder maternal sister of the Emperor, got married to a retainer was unprecedented, and surprised the people. The fact seemed to be that, after her mother, Onshi, died, she felt lonely, and had affairs with Morosuke whose wife, Imperial Princess Masako (or Gashi), had just died, before the official procedures for marriage took place, and "Okagami" (the Great Mirror) introduces an episode where FUJIWARA no Saneyori revealed her unprincipled behavior in front of her younger brother, Emperor Murakami.
In 955, she gave birth to the eleventh son (who entered the priesthood later, and was named Shinkaku) of Morosuke at the later age of thirty six.
She subsequently became pregnant, but she seemed to feel very sick at the time, and "Eiga monogatari" (a Tale of Flowering Fortunes) introduces an episode that she often told her husband about, 'I have a prophecy.'
Her prophecy unfortunately came true, and she passed away due to puerperia in 956 after giving birth to the twelfth son of Morosuke. The twelfth son, who became a bereaved child, was taken to the Imperial Court which was the family house of his mother, and was fostered by Emperess FUJIWARA no Anshi who was her elder sister by a different mother. The twelfth son was later FUJIWARA no Kinsue.
It has been identified that the body of Imperial Princess Yasuko was cremated at the riverbed of Katsura-gawa River (Yodo-gawa River system), but the location of her tomb is unidentified because there is no record.
Different from Imperial Princess Isoko (or called Kinshi) and Imperial Princess Masako who were the former wives of Morosuke and her elder sisters with a different mother, no Waka remains because Imperial Princess Yasuko had no talent for composing Waka; however, since she seemed to be good with her hands and was dedicated, it is said that many pairs of Japanese socks sewn for her husband, Morosuke, were found when opening a box among her belongings after her death.