In Japanese mythology, what eight-headed serpent-dragon was defeated by the storm god Susanoo?

In Japanese mythology, Yamata no Orochi was the eight-headed serpent-dragon defeated by the storm god Susanoo.

The creature appears in the Kojiki and Nihon Shoki, Japan’s foundational chronicles, where it is described as having eight heads and eight tails. Its enormous body stretches across valleys and hills, and trees grow on its back. Each year, Orochi demands a daughter from an elderly couple in the land of Izumo.

Susanoo promises to save their last daughter, Kushinadahime, by disguising her and preparing eight vats of strong sake. The serpent drinks from the vats, becomes intoxicated, and falls asleep. Susanoo then cuts apart its bodies and discovers the sword Kusanagi-no-Tsurugi in one of its tails.

Orochi is sometimes simply called a dragon in modern summaries, but the original descriptions emphasize a giant serpent. Kusanagi later becomes one of Japan’s Imperial Regalia.