The , , , or Worochi-no-Aramasa is the legendary sword of the Shinto god Susanoo

Susanoo

, also known as is the Shinto god of the sea and storms. He is also considered to be ruler of Yomi.-Myths:In Japanese mythology, Susanoo, the powerful storm of Summer, is the brother of Amaterasu, the goddess of the sun, and of Tsukuyomi, the god of the moon. All three were born from Izanagi, when...

. It was also the sword used by Izanagi

Izanagi

is a deity born of the seven divine generations in Japanese mythology and Shinto, and is also referred to in the roughly translated Kojiki as "male-who-invites" or Izanagi-no-mikoto. It is also pronounced Izanaki-no-Okami....

 to kill his offspring, Kagu-tsuchi

Kagu-tsuchi

, also called , , or , is the kami of fire in Japanese mythology.-Mythology:Kagu-tsuchi's birth burned his mother Izanami, causing her death. His father Izanagi, in his grief, beheaded Kagu-tsuchi with his sword, Ame no Ohabari , and cut his body into eight pieces, which became eight volcanoes...

.

History

It's never referred when it was forged or by whom; but the storm god (Susanoo) had it with him when he was banished from heaven. According to "Nihongi: Chronicles of Japan from the Earliest Times to A.d. 697" page 57, its now hold in the Kambe of Kibi

The Legend

After the sword's owner, Susanoo, was banished from heaven by the reason of killing one of Amaterasu´s Attendants and destroying her rice fields, he descended to the Province of Izumo where he met Ashinazuchi, an elderly man who told him that the Yamata no Orochi ("Eight-Branched Serpent"), who had consumed seven of his eight daughters, was coming soon to eat the last one: Kushinada-hime.
Susanoo decided to help the family and investigated about the creature, soon he begged
Ashinazuchi permission to marry Kushinada-hime, which was granted; having his plan ready, he transformed his wife into a comb so he could have her near in the battle.
As the great snake came, it put each one of his eight heads through the gates the god built, searching for the daughter; as a bait the god had put big amounts of sake after each gate, the snake took the bait and got drunk; having an easy chance, Susanoo took the Worochi no Ara-masa and cut every head off the snake, proceeding with the tails, in the fourth one he found an exceptionally great sword, the Kusanagi-no-Tsurugi.
Having the sword in his hands he returned to the heaven offering the sword as a reconciliation gift to his sister Amaterasu.

The Kojiki version

So, having been expelled, [His-Swift-impetuous-Male-Augustness] descended to a place [called] Tori-kami at the head-waters of the River Hi in the Land of Idzumo. At this time some chopsticks came floating down the stream. So His-Swift-Impetuous-Male-Augustness, thinking that there must be people at the head-waters of the river, went up it in quest of them, when he came upon an old man and an old woman, --two of them,--who had a young girl between them, and were weeping. Then he deigned to ask: "Who are ye?" So the old man replied, saying: "I am an Earthly Deity, child of the Deity Great-Mountain-Possessor. I am called by the name of Foot-Stroking-Elder, my wife is called by the name of Hand-Stroking Elder, and my daughter is called by the name of Wondrous-Inada-Princess." Again he asked: What is the cause of your crying?" [The old man answered] saying: "I had originally eight young girls as daughters. But the eight-forked serpent of Koshi has come every year and devoured [one], and it is now its time to come, wherefore we weep." Then he asked him: "What is its form like?" [The old man] answered, saying: "Its eyes are like akahagachi, it has one body with eight heads and eight tails. Moreover on its body grows moss, and also chamaecyparis and cryptomerias. Its length extends over eight valleys and eight hills, and if one look at its belly, it is all constantly bloody and inflamed." (What is called here akakagachi is the modern hohodzuki [winter-cherry]) Then His-Swift-Impetuous-Male-Augustness said to the old man: "If this be thy daughter, wilt thou offer her to me?" He replied, saying: "With reverence, but I know not thine august name." Then he replied, saying: "I am elder brother to the Heaven-Shining-Great-August-Deity. So I have now descended from Heaven." Then the Deities Foot-Stroker-Elder and Hand-Stroking-Elder said: "If that be so, with reverence will we offer [her to thee]." So His-Swift-Impetuous-Male-Augustness, at once taking and changing the young girl into a multitudinous and close-toothed comb which he stuck into his august hair-bunch, said to the Deities Foot-Stroking-Elder and Hand-Stroking-Elder: "Do you distil some eight-fold refined liquor. Also make a fence round about, in that fence make eight gates, at each gate tie [together] eight platforms, on each platform put a liquor-vat, and into each vat pour the eight-fold refined liquor, and wait." So as they waited after having thus prepared everything in accordance with his bidding, the eight-forked serpent came truly as [the old man] had said, and immediately dipped a head into each vat, and drank the liquor. Thereupon it was intoxicated with drinking, and all [the heads] lay down and slept. Then His-Swift-Impetuous-Male-Augustness drew the ten-grasp sabre that was augustly girded on him, and cut the serpent in pieces, so that the River Hi flowed on changed into a river of blood. So when he cut the middle tail, the edge of his august sword broke. Then, thinking it strange, he thrust into and split [the flesh] with the point of his august sword and looked, and there was a great sword [within]. So he took this great sword, and, thinking it a strange thing, he respectfully informed the Heaven-Shining-Great-August-Deity. This is the Herb-Quelling Great Sword. (tr. Chamberlain 1919:71-3)