In "Genji Monogatari" (The Tale of Genji), a literary work of this period, we can find many cases of koka such as Omiya (the lawful wife of the Sadaijin [Minister of the left] and the mother of Aoi no ue [Lady Aoi]), Onna Sannomiya (the lawful wife of Hikaru Genji), Ochiba no miya (the lawful wife of Kashiwagi, who later remarried to Yugiri), and Onna Ninomiya (the lawful wife of Kaoru) and so on.
同時代の文学作品である『源氏物語』においても、大宮(源氏物語)（左大臣正室、葵の上の母）、女三宮（光源氏正室）、落葉の宮（柏木(源氏物語)正室、のち夕霧(源氏物語)と再婚）、女二宮（薫正室）などの例が見られる。