Koonji Temple is a historic temple of the Koyasan Shingon school of Buddhism located in Akaiwa, Chiyoda Town, Gunma Prefecture. It is widely known by its popular name, Akaiwa Fudoson, after Fudo Myoo, the Buddhist deity of wisdom and protection enshrined here.
Situated in a peaceful area on the left bank of the Tone River, Koonji is said to have a history of more than 1,200 years. As one of the oldest temples in Chiyoda Town, it has long been an important center of religious faith for the local community.
The temple stands in an area where people have lived since ancient times. Its grounds preserve numerous treasures designated as Important Cultural Properties of Japan and Gunma Prefecture, as well as historically valuable buildings such as a traditional gate relocated from the birthplace of Ogino Ginko, known as Japan’s first officially licensed female physician.
With seasonal flowers and trees surrounding its historic buildings and cultural treasures, Koonji has also been selected as one of the 100 Scenic Sites of Gunma.
Several old temple traditions describe the origins of Koonji. According to one tradition, the temple was among nine temples established throughout Japan during the reign of Emperor Yuryaku for the imperial palace of Anaho.
Another tradition states that in 603, during the reign of Empress Suiko, the court official Hata no Kawakatsu visited the area as an imperial envoy and enshrined three Buddhist relics.
It is also said that in 625, the Korean monk Ekkan came to the region while spreading Buddhist teachings in eastern Japan. At the request of a local powerful family, he visited this area and taught the doctrines of the Sanron school of Buddhism, an event regarded in some traditions as part of the temple’s origins.
According to temple tradition, in 814, the Buddhist monk Kobo Daishi Kukai, founder of Shingon Buddhism, stayed here while traveling through Japan. He is said to have restored Koonji as a center for Esoteric Buddhist practice.
Kukai is also traditionally believed to have carved a wooden statue of Jizo Bodhisattva himself and enshrined it at the temple. Because of this association, Koonji came to use the temple name Jizoin.
Since then, the temple has continued as a center of Shingon Buddhist practice, with more than 80 generations of head priests carrying on its religious tradition.
During the medieval period, Koonji developed as a family temple of powerful local clans. At its height, it is said to have had 16 monastic buildings and more than 3,000 affiliated temples.
Its history was not always peaceful, however. The temple buildings were repeatedly destroyed by warfare and fire and had to be rebuilt several times.
In 1321, under an order from Emperor Go-Daigo, Utsunomiya Kimitsuna oversaw the reconstruction of the temple. It was given the temple name Akaiwasan Koonji and is said to have received an estate equivalent to 700 kan of official land rights.
Later, in 1648, the temple received land and privileges from Tokugawa Iemitsu, the third shogun of the Tokugawa shogunate. These privileges included exemptions relating to its forests and certain duties, further establishing Koonji’s status as an important regional temple.
The present main hall was rebuilt in 1883. It has survived despite the fires and conflicts that affected the temple over its long history.
Inside the hall is the temple’s principal image, a secret statue of Fudo Myoo. The statue is normally kept hidden and is revealed to the public only on special occasions, including New Year’s ceremonies and certain spring and autumn Buddhist services.
The ceiling of the main hall features a huge painting of a dragon king covering an area of approximately 70 tatami mats. Known for its impressive scale, the painting is one of the highlights of the temple and offers visitors an opportunity to appreciate both Buddhist architecture and traditional Japanese art.
The temple grounds contain a bell tower along with numerous stone Buddhist figures, memorial monuments, and other religious structures. These objects reflect the layers of faith accumulated by generations of worshippers.
The sound of the temple bell adds to the peaceful atmosphere of the grounds and creates a quiet sense of connection with the temple’s long history.
Near the entrance stands a historic Nagayamon gate dating from the late Edo period. It was relocated from the birthplace of Ogino Ginko, who is known as Japan’s first officially licensed female physician.
The gate was moved to Koonji during the Meiji period and has been carefully preserved. It is designated as a Registered Tangible Cultural Property of Japan, making it an important architectural link between the history of Ogino Ginko and the cultural heritage of the temple.
Koonji preserves numerous cultural properties designated by the national and prefectural governments and is known for having one of the notable collections of Buddhist treasures in northern Kanto.
Among the most valuable objects is a set of five bronze ritual bells believed to date from the Kamakura period. The set consists of a jewel bell, pagoda bell, five-pronged vajra bell, three-pronged vajra bell, and single-pronged vajra bell.
The bells are decorated with elegant lotus and arabesque patterns and Sanskrit characters. They provide a rare glimpse into the solemn rituals and material culture of Esoteric Buddhism in medieval Japan.
The temple also preserves an Amida Triad, believed to have been created during the early Kamakura period. The group consists of Amida Buddha in the center, accompanied by Kannon Bodhisattva and Seishi Bodhisattva.
The central Amida statue stands approximately 2.4 meters tall and displays the elegant artistic style associated with the Jocho tradition.
Although the temple buildings were destroyed during the Yuki War, the three statues are said to have miraculously survived. Because they escaped the destruction, the Amida statue became known as the “Amida who escaped the fire.”
A stone memorial stele dedicated to Jizo Bodhisattva was erected in 1271. It is considered one of Japan’s oldest surviving examples of a Jizo image stele.
Known locally as the “Nail-Pulled Jizo,” it has been an object of popular devotion for centuries.
The temple grounds are also home to the Akaiwa Doyama Kofun, a large keyhole-shaped burial mound believed to have been constructed in the early seventh century.
The mound measures approximately 90 meters in length, making it one of the largest kofun in the Oura-Tatebayashi area. Its presence indicates that this region was already an important center during ancient times.
A bell tower and gorinto five-ring Buddhist memorial stones stand on the mound, creating a distinctive landscape where an ancient archaeological site and Buddhist culture exist side by side.
Walking around the grounds offers a rare opportunity to encounter layers of history extending from ancient Japan through the medieval and early modern periods.
The temple’s mountain name is Akaiwasan, derived from the place name Akaiwa, where the temple stands. Local tradition holds that the area once had exposed red rock surfaces, which gave the settlement its name.
The name Koon expresses the idea of people being saved by the compassionate light of the Buddha and receiving the blessings of that compassion.
Throughout its long history, Koonji has served as a spiritual center and an important place of faith for the local community.
A visit to Koonji is about more than simply praying at the main hall. Visitors are encouraged to take time to explore the grounds and discover the Nagayamon gate, stone Buddhist figures, burial mound, historic buildings, and cultural treasures.
Walking through the peaceful temple grounds provides a sense of how the temple developed and survived through more than a millennium of Japanese history.
Surrounded by the natural landscape along the Tone River, Koonji also offers a tranquil setting in which to enjoy the changing seasons. The surrounding rural scenery adds to the peaceful atmosphere.
The grounds of Koonji are known for their seasonal trees and flowers, making the temple an attractive destination throughout the year.
Plum blossoms, camellias, cherry blossoms, and azaleas bloom in succession, transforming the grounds into a colorful spring landscape. Visitors can enjoy several varieties of cherry trees, including Somei Yoshino and weeping cherry trees.
Summer brings lotus flowers, water lilies, hydrangeas, and crape myrtles. Their vivid colors contrast beautifully with the quiet atmosphere of the historic temple grounds.
In autumn, colorful foliage appears alongside October cherry blossoms. A particularly striking feature is the temple’s large ginkgo tree, whose leaves turn brilliant golden yellow.
During winter, camellias, sasanqua camellias, and narcissus bloom quietly, creating a peaceful seasonal landscape.
Koonji holds various Buddhist ceremonies and events throughout the year. Among the best known are the Fudo Myoo Grand Festivals held in spring and autumn.
Held annually on March 28, the spring festival features Shoto Goma, a sacred fire ritual in Esoteric Buddhism, as well as a traditional fire-walking ceremony. Many worshippers visit the temple for the event.
The autumn festival includes Goma fire rituals and the chanting of the Great Prajnaparamita Sutra, along with distinctive cultural events such as an Indian dance performance. The temple grounds become lively with visitors and worshippers.
Koonji Temple is not only an ancient Buddhist temple but also a remarkable cultural destination where historic buildings, archaeological remains, religious treasures, and seasonal scenery come together.
The combination of the ancient kofun, historic architecture, Buddhist treasures, and flowers throughout the seasons gives visitors a unique opportunity to experience different layers of Japanese history in one peaceful setting.
Surrounded by the natural landscape of the Tone River and a rural countryside atmosphere, Koonji offers a quiet place to explore the history and culture of Chiyoda Town while appreciating the beauty of Japan’s changing seasons.