Gaya-in, known as a training ground for yamabushi (mountain ascetics), is a power spot where the largest Saiden Dai Gomaku (fire ritual) in the Kinki region takes place.
Gaya-in is a Honzan Shugendo Buddhist temple located in Miki City, Hyogo Prefecture. Its mountain name is Ohtaniyama, and its principal deity is Bishamonten. Known as a temple for yamabushi (mountain ascetics), it is also the 26th temple on the New Saikoku Thirty-three Kannon Pilgrimage. Legend states that Gaya-in was founded in 645 AD by Hoto Sennin as a temple commissioned by Emperor Kotoku. During the mid-Heian period, it prospered, boasting dozens of halls and over 130 monastic quarters, with recorded visits from Emperor Kazan. However, it suffered immense damage from fires during the Battle of Miki in the Azuchi-Momoyama period, when the forces of Bessho Nagaharu were stationed on the temple grounds. A further fire in 1609 destroyed nearly everything, leaving only the stone walls. The existing halls and pagodas were rebuilt after 1610 thanks to donations from various daimyo (feudal lords). In 1681, by imperial decree from Emperor Gosai, the temple was renamed Gaya-in, after Buddha Gaya. From the medieval period onwards, it held significant power as a Shugendo temple under the Shogo-in temple, and in the Edo period it was one of the four influential temples controlling Tendai-sect yamabushi, wielding significant influence in the Shugendo world. Even today, numerous yamabushi gather from various regions on Sports Day in October for the Saiden Dai Gomaku, the largest fire ritual in the Kinki region. Gaya-in possesses numerous important cultural properties, including the Golden Hall, multi-storied pagoda, and the Kaizan-do (founder's hall). The grave of Zuan Osho is also located within the temple grounds. Gaya-in is beloved by many as a power spot where history and nature intertwine.