Koshikibu no Naishi

 was a Japanese "waka" poet of the early eleventh century. One of her poems was included in the "Ogura Hyakunin Isshu".
Biography.
She was the daughter of Izumi Shikibu and , the governor of Mutsu.
Starting around 1009, she joined her mother in serving Empress Shōshi.
A target of many suitors, she eventually married . She bore him a child, but died thereafter, still in her late twenties.
Poetry.
Four of her poems were included in imperial anthologies such as the "Goshūi Wakashū" and the "Kin'yō Wakashū".
"Ōe-yama".
The following poem by her was included as No. 60 in Fujiwara no Teika's "Ogura Hyakunin Isshu":
In later literature.
Numerous anecdotes about her were incorporated into later and "setsuwa" collections.
An "otogizōshi", "Koshikibu", was also written.