Akagi Shrine

Akagi Shrine stands on Kotori Island, a small island in Lake Ōno (elevation 1,345 m), which floats within the caldera of Mount Akagi's summit (1,828 m). Situated in Maebashi, Gunma Prefecture, it forms one of three affiliated shrines—collectively known as the Akagi Three Shrines—together with Miyosawa Akagi Shrine and Ninomiya Akagi Shrine at the mountain's base.

The principal enshrined kami (shusaijin) is Akagi-no-Okami, a composite deity uniting Ōkuninushi-no-Kami (the great land-holding deity of Izumo tradition) and Toyoki-Irihiko-no-Mikoto, an imperial prince and ancestor of the Kōzuke provincial governors. Secondary kami include Iwatsutsu-o-no-Kami and Iwatsutsu-me-no-Kami. From the medieval period onward, the principal deity has been understood as a great serpent or dragon inhabiting the lake—the lake's sovereign spirit. Akagi Shrine is renowned in folklore for the "Akagi-Nikkō Divine War," a legendary territorial dispute between this mountain's dragon and the great centipede deity of nearby Mount Nikkō.

According to shrine tradition, veneration began during the reign of Emperor Sujin, when the imperial prince Toyoki-Irihiko-no-Mikoto governed the eastern provinces. The *Engishiki* (Procedures of the Engi Era, 927 CE) lists "Akagi Shrine" in the *Jinmyocho* (Register of Shrines) for Seta County, Kōzuke Province, conferring on it the rank of major shrine and second-rank shrine of Kōzuke. The medieval period saw the shrine develop as a training ground for *Shugendo* (mountain-ascetic practice) under both Tendai and Shingon auspices, inspired by dragon-serpent lore. During the Edo period, the Numata and Maebashi domains granted it their patronage. Following the Shinto-Buddhist separation (shinbutsu-bunri) of the Meiji era, the shrine was reorganised and designated a former prefectural shrine. The main sanctuary was relocated to Kotori Island in 1970, establishing it as a shrine within the lake itself.

The principal annual rites are the May 5 Grand Festival, autumn festival in October, and hatsumode (first shrine visit of the New Year) in January. The Grand Festival features sacred rites on the lake surface that preserve ancient practices, with coordinated rituals between the summit sanctuary and the base shrines. Winter snow and ice restrict pilgrim access; worship concentrates between spring and autumn.