Yamata-no-Orochi (八岐大蛇 lit. large snake divided into eight) is a monster in Japanese mythology. He is described in the Shinto books Kojiki and Nihonshoki as a deity who lived in the area called Torikami, in the country of Izumo.
Although it is also said to be a Japanese version of the Lerna hydra. It has eight heads and eight tails, which is why it is called "Yamata". "Orochi" means "giant snake", and is usually worshipped as the mountain deity in Shinto.
In a region called Torikami, above the Hi-no-kawa river of the ancient land of Izumo, a holy prince came down expelled from heaven: Takama-ga-hara. The son of Izanagi and brother of the Sun goddess Amaterasu, his name was Susanowo-no-mikoto.
Arriving at the river, he saw a small stick floating by, and so he continued his way upstream thinking that there might be people living there. Before long he found an old couple sobbing with a girl beside them. The god asked them who they were and what was wrong with them.
The old man replied, "I am a son of the god of the country Oyamatsumi-no-kami and my name is Ashinazuchi. My wife is Tenazuchi, and our daughter is Kushinada."
He also explained to her that Orochi ruled the province, and demanded virgin sacrifices.
"We had eight daughters, but Yamata-no-Orochi swallowed them one by one every year, and we have only our youngest daughter left. And now the monster is coming to get her. That's why we are crying like this." Susano'o asked him, "What shape is she in?"
The old man answered, "Its eyes are red like alquequenjes, and it has a body with eight heads and eight tails. Its size comes to occupy eight valleys and eight hills. Its belly is always swollen and covered with blood." Although in none of his representations does Yamata appear in full body.
Susano'o, who had fallen in love with the young woman, said to her, "Will you let me marry your daughter if I save her?" The man replied, "I thank you for your interest, but I do not yet know your name." "I am the brother of Amaterasu-Omikami.
And I just came down from Takama-ga-hara," he replied. The couple told him, "Oh, if you deign to do this, our daughter is yours." Susano'o turned the girl into a sacred comb and put it in her hair, and said, "Prepare a well-distilled liquor. Surround your house with fences, and make you eight doors and eight boxes. Leave a cup in each box, pour in the liquor, and wait."
They prepared everything just as Susano'o ordered them, and waited. After a while Yamata-no-Orochi appeared. Immediately Orochi put their heads into the cups and drank. He became drunk and fell asleep there. Then Susano'o drew his three-foot sword (Totsuka-no-tsurugi) and cut the snake into pieces. The river became stained with blood.
When he cut off the middle tail, his sword splintered. Strangely, he slit the tail with the tip of the blade, and inside he discovered another sword, Murakumo-No-Tsurugi, which would later be called Kusanagi (草薙, Grass Cutter) by Yamato Takeru. He then took that sword and presented Amaterasu with it, telling her what had happened.