Komo Shrine, also known as Ōsada Shrine, is believed to be the predecessor of Usa Jingū, the head shrine of all Hachiman shrines across Japan. The first shrine buildings were constructed sometime between 834 and 848 (Jōwa era). Later, in 1109 (Tennin era), a seven-temple complex was built adjoining the shrine.
Behind the main hall lies Misumi Pond, a triangular pond that itself serves as a sacred object of the shrine. During the Hayato Rebellion in 720 (Nara era), pillows made from makomo reeds growing in the pond were placed on the sacred palanquin as a divine sign of the Usa Hachiman deity. Ever since, reed pillows have symbolized the deity’s divine authority.