A Sacred Site in Oami Traditionally Founded by Kukai
According to temple tradition, Dainichibo was founded in 807 by Kukai, while his disciple Tokai is said to have established the temple.
The temple stands at the Oami entrance, one of the traditional approaches to the sacred mountains of Dewa Sanzan, the “Three Sacred Mountains of Dewa.” It has therefore been closely connected with mountain worship and Shugendo, a Japanese tradition of ascetic religious practice in the mountains, since ancient times.
The official Dewa Sanzan Shrine tradition identifies Prince Hachiko as the founder of worship on Dewa Sanzan, while Dainichibo and the nearby Churenji Temple preserve traditions identifying Kukai as their founder. These differing traditions reflect the complex religious history that developed around the sacred mountains.
The name Oami is sometimes explained in connection with the expression “Daiani,” referring to Dainichi Nyorai, the Cosmic Buddha associated with Yudonosan, and Amida Nyorai, the Buddha associated with Mount Gassan. Local tradition also describes Oami as a sacred place purified and established by Kukai.
Yudonosan has traditionally been regarded as a sacred site with a spiritual relationship to Mount Koya, the center of Shingon Buddhism established by Kukai.
A Temple That Supported the Mountain Worship of Dewa Sanzan
Dainichibo was once one of the four major temples of the Yudonosan school, serving as an important center for the mountain worship and Shugendo traditions associated with Dewa Sanzan.
Located along one of the pilgrimage routes to Yudonosan, the temple attracted worshippers over many generations. In earlier times, the temple grounds were much larger than they are today, with an extensive complex reportedly measuring approximately 42 ken wide and 12 ken deep.
However, the temple suffered major disasters over the centuries. A fire in 1875 caused significant damage, followed by a landslide in 1936. As a result, the temple was relocated to its present site, where its religious traditions continue today.
A Deep Connection with the Tokugawa Shogunate
Dainichibo is particularly notable for its historical connection with the Tokugawa shogunate during the Edo period.
In 1640, Kasukaga no Tsubone, the wet nurse of Tokugawa Iemitsu, is said to have visited Dainichibo. After the birth of Tokugawa Ietsuna, Iemitsu is traditionally said to have presented an image of Dainichi Nyorai of the Diamond Realm to the temple as an expression of gratitude for the safe birth of his heir.
The main hall was also rebuilt through a donation by Kasukaga no Tsubone. These events strengthened the temple’s association with the Tokugawa family and remain among the best-known stories in Dainichibo’s long history.
The Secret Principal Image Known as Yudonosan Gongen
The principal object of worship at Dainichibo is Yudonosan Gongen, traditionally also referred to as a seated image of Dainichi Nyorai representing the two mandalas, the Diamond Realm and Womb Realm.
In earlier times, the mountains of Dewa Sanzan were considered nyonin kinsei, meaning women were prohibited from entering certain sacred mountain areas. Temples and shrine-associated facilities at the foot of the mountains therefore served an important role as places where women could worship Yudonosan without entering the restricted mountain area.
According to temple tradition, Kukai carved an image of Dainichi Nyorai of the two mandalas himself, making three bows with each stroke of the carving knife, so that women could also worship the sacred deity of Yudonosan.
The principal image is regarded as a secret Buddha and is traditionally shown to the public only during special openings held in the Years of the Ox and Sheep in the traditional zodiac cycle.
Sokushinbutsu: Shinnyokai Shonin
A Monk Who Undertook Decades of Severe Religious Training
One of the most famous treasures at Dainichibo is the sokushinbutsu of Shinnyokai Shonin.
Shinnyokai Shonin is traditionally said to have been born as the eldest son of a farming family in the former Asahi Village area. Following an event in his youth, he entered the priesthood at Dainichibo, motivated both by a desire to commemorate the deceased and by his devotion to Buddhism, which had been familiar to him since childhood.
He is said to have begun pursuing the path toward becoming a sokushinbutsu in his twenties and subsequently undertook more than 70 years of rigorous religious practice.
According to tradition, he continued his ascetic training while praying for people suffering from hunger and eventually entered final meditation at the age of 96.
A Rare Example of Sokushinbutsu Preserved at Dainichibo
Sokushinbutsu refers to the preserved remains of Buddhist monks who undertook extreme ascetic practices and entered a final state of meditation. Such traditions developed particularly in the mountain temples of northern Japan.
Shinnyokai Shonin is said to have died at the age of 96 in 1786. According to tradition, his body was exhumed several years later and subsequently preserved as a sokushinbutsu.
The tradition reflects the severe religious practices and spiritual beliefs of the period. The sokushinbutsu of Shinnyokai Shonin remains an important part of Dainichibo’s religious heritage and a powerful reminder of the traditions surrounding Yudonosan and Shugendo.
Nationally Designated Important Cultural Property: Gilt-Bronze Standing Image of Shaka Nyorai
Dainichibo also houses the Gilt-Bronze Standing Image of Shaka Nyorai, designated as an Important Cultural Property of Japan.
The image is traditionally said to have originated in ancient India before being transmitted through China and the Korean Peninsula and reaching Japan during the 6th century, the Asuka period.
Its history reflects the long transmission of Buddhist art and religious culture across Asia before Buddhism became established in Japan. The statue is therefore valuable not only as a work of Buddhist art but also as a reminder of the international cultural exchanges that shaped early Japanese Buddhism.
The Impressive Niomon Gate
The Niomon Gate is another architectural highlight of Dainichibo. On either side of the front are images associated with the Fujin and Raijin, the gods of wind and thunder, while farther inside stand powerful Nio guardian statues traditionally attributed to the Kamakura-period sculptor Unkei.
The Niomon is designated as a Yamagata Prefectural Cultural Property. It is also regarded as the oldest surviving three-bay, one-door, eight-legged gate of its type in Japan.
The imposing gate and powerful guardian figures create a dignified atmosphere characteristic of a temple with a long history of religious worship.
The Ancient Koda Sugi Cedar
The Kodan-no-Sugi, an enormous old cedar tree standing on the former temple grounds, is another noteworthy feature associated with Dainichibo. The tree is approximately 27 meters tall and is now also regarded by many visitors as a spiritual power spot.
The cedar is traditionally said to have been planted in memory of Prince Misowake, a son of Emperor Keiko. The immense tree, which has lived for generations, offers a tangible connection with the long history of faith rooted in this mountainous region.
Numerous Images of Kannon
Approximately 100 images of Kannon are enshrined throughout the temple grounds. Walking through the temple and viewing the many forms of Kannon provides an opportunity to appreciate the richness and diversity of the religious culture centered on Yudonosan.
Each feature of the temple—from the principal image and sokushinbutsu to the Buddhist statues, Niomon Gate, and ancient cedar—has its own story. Learning about these stories transforms a visit from simply viewing historic buildings into a deeper encounter with the religious history of the region.
An Ancient Temple Preserving the History of Yudonosan Worship
Ryusuiji Dainichibo is an important temple for understanding the religious history of the Shonai region. Its traditions encompass the founding legend associated with Kobo Daishi Kukai, the mountain worship of Dewa Sanzan, Shugendo, historical ties with the Tokugawa shogunate, and the tradition of sokushinbutsu.
The temple’s many highlights include the secret principal image of Yudonosan Gongen, the sokushinbutsu of Shinnyokai Shonin, the nationally designated Important Cultural Property of Shaka Nyorai, the imposing Niomon Gate, and the ancient Kodan-no-Sugi cedar.
When visiting Yudonosan, taking time to consider not only the beauty of the mountains but also the long history of faith and culture that developed around them can provide a deeper understanding of this sacred landscape.
Dainichibo remains one of the historic temples of the Shonai region where the traditions of Dewa Sanzan mountain worship and Yudonosan faith continue to be preserved today.