The Tosa Nikki (Tosa Diary) is a poetic diary written anonymously by the tenth-century Japanese poet Ki no Tsurayuki. The text details a 55-day journey in 935 returning to Kyoto from Tosa province, where Tsurayuki had been the provincial governor. The prose account of the journey is punctuated by Japanese poems, purported to have been composed on the spot by the characters.
The Tosa Nikki is the first notable example of the Japanese diary as literature. Until its time, the word “diary” (nikki) denoted dry official records of government affairs, written by men in Chinese. By contrast, the Tosa is written in the Japanese language, using phonetic kana characters. Literate men of the period wrote in both kana and Chinese, but women typically were not taught the latter, being restricted to kana literature. By framing the diary in the point of view of a fictitious female narrator, Tsurayuki could avoid employing Chinese characters or citing Chinese poems, focusing instead on the aesthetics of the Japanese language and its poetry.