Shinobi Uta is a song cycle in five movements for soprano, baritone, and chamber orchestra based on the story of Tosa Nikki. The first literary work in Japanese history conveyed in the form of a diary, Tosa Nikki was written by one of the most renowned poets and writers of its time, Tsurayuki Kino, in 935. His refined skills in Japanese and Chinese poetry were highly acknowledged by the Japanese imperial court during the Heian Period (794-1185). His name often appears in many of the early Japanese anthologies of poetry including the first of its kind called Kokin Wakashu, for which he was appointed one of the four editors responsible for compiling more than a thousand poems from this period. In Tosa Nikki, the author recounts a series of events during his 55-day journey back to Kyoto (then the capital of Japan) from the province of Tosa, where he had been appointed the governor for five years, and also includes 57 poems.

The most fascinating aspect of Tosa Nikki is the fact that Tsurayuki wrote the entire work from the perspective of an anonymous female, only mentioning himself in the third person. His intention is evident from the very first line of the diary: “They say that writing diaries is for men, but as a woman, I am going to give this a try.” In order to emphasize the female voice, he used only phonetic characters (Kana), which were considered to be the writing method for women, as opposed to ideographic characters (Kanji) for men. Tsurayuki’s motive for hiding his gender is not certain, but one can speculate that he was greatly influenced by the loss of his young daughter during his stay in Tosa. Throughout the diary, the author repeatedly reminds the reader of this matter by mentioning a grieving couple (Tsurayuki and his wife). Perhaps assuming the tone of a female writer allowed Tsurayuki to express his deep sorrow more simply and intimately.