What legendary sword was found in the tail of Yamata no Orochi?

The legendary sword found in the tail of Yamata no Orochi was Kusanagi.

In the Japanese creation myths, the storm deity Susanoo encountered Yamata no Orochi, an eight-headed, eight-tailed serpent terrorizing a family in Izumo. Susanoo made the monster drink from eight vats of strong sake, then killed it while it was incapacitated. Cutting through the serpent’s tails, he discovered a sword inside the fourth tail.

The blade was originally called Ame-no-Murakumo-no-Tsurugi, or “Sword of the Gathering Clouds of Heaven.” It later became known as Kusanagi-no-Tsurugi, commonly translated as “Grass-Cutting Sword.” Susanoo presented it to his sister Amaterasu, helping repair their relationship. The sword became one of Japan’s Three Imperial Regalia, alongside the Yata no Kagami mirror and Yasakani no Magatama jewel.

A common mix-up is confusing the discovered sword with the weapon Susanoo used to kill the serpent. Those are treated as separate blades in some textual traditions. Kusanagi’s later legend centers on Yamato Takeru, who used it to cut grass and escape a fire; tradition associates the sword with Atsuta Shrine, though it is not publicly displayed.