Morioka Sansa Odori in Morioka
Morioka Sansa Odori is an August 1-4 festival in Iwate Prefecture rooted in an Edo-period legend of a demon banished by a local deity, whose joyful dance and chant gave the event its name. Its parade of over 30,000 taiko drummers, flutists, and dancers holds the Guinness World Record for the largest ensemble performance of traditional Japanese drums, with 3,437 participants.
According to local legend passed down through generations in Morioka, a troublesome demon once tormented the town from within its castle grounds until the resident deity of a local shrine captured the creature and forced it to swear never to commit evil again, at which point it fled the area entirely.