The Tosa Nikki (Tosa Diary) describes the river as the Katsura-gawa River, '桂川'; in the Nihon Kiryaku (historical books written in the Heian period), the river is known as the Oi-gawa River, '大堰川'; and in the Tsurezure-gusa (a collection of essays written in the early 1330s), the river is referred to as the Oi-gawa River, '大井川.'
「土佐日記」では桂川の字を、「日本紀略」では大堰川の字を、「徒然草」では大井川の字を見ることができる。