Banished from the High Plain of Heaven, Susanoo came down at a place called Torikami, upstream on the Hi River (the Hii) in the land of Izumo. Chopsticks came floating down the river, so he knew people lived upstream. Going up, he found an old man and an old woman weeping, with a young girl between them. The old man was Ashinazuchi, the old woman Tenazuchi, and the girl Kushinada-hime.
They told him they once had eight daughters, but every year the eight-headed serpent of Koshi came and ate one, and now its time had come again. Its eyes were red as ground cherries; it had one body with eight heads and eight tails; moss, cypress and cedar grew on its back; it stretched across eight valleys and eight peaks; and its belly was always raw and dripping blood.
Susanoo arranged to take the girl as his wife, turned her into a comb and put it in his hair. Then he had the old couple brew a strong sake, eight times refined, build a fence with eight gates, and set a vat full of sake at each gate. The serpent came, dipped each of its eight heads into a vat, drank, and fell into a drunken sleep. Susanoo drew his ten-span sword and hacked the serpent to pieces, and the Hi River ran red with blood.
When he cut into the middle tail, the edge of his sword chipped. Puzzled, he split the tail open and found a keen great sword inside. This was the sword Kusanagi, and Susanoo presented it to Amaterasu. Later he built a palace at Suga, and when clouds rose there in great billows he composed the song that begins "Eight clouds rise."