Gion-shinko Faith (祇園信仰)
"Gion-shinko Faith" is a belief in Gozu Tenno (deity said to be the Indian god Gavagriva), Susanoo, and is a syncretism of Shinto and Buddhism. After the separation of Buddhism and Shintoism, it became a Shinto faith honoring Susanoo as an enshrined deity. The Yasaka-jinja Shrine in Kyoto is the sohonsha (chief shrine).
Gozu Tenno was originally a Buddhist god, and the guardian deity of Gion shoja Temple. It was influenced by Taoism in China before arriving in Japan, and it synchronized with the Shinto god (Shinto), Susanoo, in Japan. This is because Gozu Tenno and Susanoo were both considered gyoyaku jin (gods that spread epidemics). Yakushi nyorai (Bhaisaya, buddha able to cure all sickness) was the honjibutsu (original Buddhist divinity).
The original form of the Gion-shinko Faith was for the prevention of epidemics by solacing and calming the gyoyaku jin, based upon Goryo-shinko Faith, which developed during the Heian period. Its religious festival was called 'Gion Goryo-e,' and began being celebrated by the citizens of Kyoto at the Gion-sha Shrine (currently Yasaka-jinja Shrine) in the latter half of the tenth century. Gion Goryo-e became established as an annual celebration in June at the Gion-sha Shrine, and in 975, became a festival where hohei (offering a wand with hemp and paper streamers to a Shinto god) is performed by the Imperial Court. This festival later became the Gion-matsuri Festival. Festival cars and floats mounted with decorative halberd entertain the gyoyaku jin, and are also meant to disperse the bad luck of gyoyaku jin. By medieval times, the Gion-shinko Faith spread nationwide, Gion-sha Shrines or Gozu-Tennosha Shrines enshrining Gozu Tenno were built, and Goryo-e (or Tenno-sai Festival) were held as celebrations.
The order for the separation of Buddhism and Shintoism in Meiji prohibited Buddhist rituals at shrines, as well as the use of Buddhist terms such as 'Gozu Tenno' and 'Gion' in names of enshrined deities and shrines, and thus, Gion-sha Shrine and Gozu-Tennosha Shrine became shrines enshrining Susanoo and changed their shrine names. Gion-sha Shrine in Kyoto, which is the sohonsha, became Yasaka-jinja Shrine due to its place of enshrinement. Following Kyoto, other shrines changed their names to Yasaka-jinja Shrine, to Susano-jinja Shrine from the name of the enshrined deity, to Gion-jinja Shrine from the previous shrine name, to names prefixed with geographic names, or to old shrine names used before enshrining Gozu Tenno.
Among the faiths for Gozu Tenno, the Susanoo, faith centered around Tsushima-jinja Shrine (Tsushima City, Aichi Prefecture) spreading to the Tokai region of Honshu, is called the Tsushima-shinko Faith, and faith centered around Hikawa-jinja Shrine (Omiya Ward, Saitama City, Saitama Prefecture) spreading to the Kanto area, is called the Hikawa-shinko Faith.