According to Japanese mythology, Susanoo-no-mikoto was traveling around Japan and stopped at the residence of Somin Shorai seeking shelter for the night. Somin Shorai gladly offered Susanoo-no-mikoto lodging for the night despite being very poor himself. Years later as a gesture of thanks, Susanoo-no-mikoto again visited Somin Shorai and told him that if an epidemic were to occur, Somin Shorai should make it known who his descendants were and wrap large thatch ropes around their waists to prevent infection.
Every year on July 31st, there is a religious rite held at Ekijin Shrine (a small shrine attached to Yasaka shrine) dedicated to Susanoo-no-mikoto known as the Nagoshisai Matsuri, which is the closing event for the entire Gion Matsuri festival. At the Nagoshisai ceremony, visitors hang protective charms on a large thatch rope (with a diameter of 2 meters) tied across the torii gates. These charms have the words "I am descended from Somin Shorai" inscribed on them. The chimaki (bamboo leaf talismans) sold at Yamaboko-machi during the Gion Matsuri are named after Somin Shorai and the thatch rope he wrapped around his waist, and they are used as talismans to ward off evil and hung on the doors of homes throughout the year until the next Gion Matsuri.