Mount Koka is a mountain standing 1,224.20 meters above sea level in the eastern part of the Etsumi Mountains, straddling Gujo City and Seki City in Gifu Prefecture. It lies near the northern edge of the Nōbi Plain, in the middle reaches of the Nagara River, and is also known as Kōgadake.
Since ancient times, the mountain has been an important center of Kōga-san worship, a tradition associated with Shugendō, a form of Japanese mountain asceticism that combines Buddhist and Shinto beliefs with rigorous spiritual training in nature. Kōga Shrine stands at the foot of the mountain and is closely associated with its religious history. According to tradition, the shrine was founded by Fujiwara no Takamitsu during the Yōrō era (717–724).
Mount Koka has well-maintained hiking trails and is relatively accessible even for beginners. From the summit, hikers can enjoy panoramic views of Mount Ontake, Mount Hakusan, and the mountains of Oku-Mino.
Kōga Shrine, founded during the Nara period (710–794), is located in the Horado area at the foot of the mountain, approximately 2.5 kilometers south-southeast of the summit. The mountain has long been known as a sacred destination for mountain worship.
The name Kōga is associated with a legend about Fujiwara no Takamitsu, who defeated a monster that had appeared on nearby Mount Fukuragadake, also known as Mount Fūga, and terrorized the local villagers.
During the Edo period (1603–1868), the Buddhist sculptor and itinerant monk Enkū climbed Mount Koka and left behind numerous Buddhist statues in the surrounding area. Because of this connection, the Seki City Horado Enkū Memorial Museum was established nearby. Mount Koka can also be seen from the large torii gate at the foot of Kōga Shrine.
Along the Miyashita Forest Road, which follows the upper reaches of the Kōga River from the shrine, Kōga Forest Park has been developed for visitors. The mountain itself is composed of rhyolitic rocks.
The historical geographical text Shinsen Mino-shi describes the mountain as follows: “Seen from afar, it resembles an arrow notch; therefore, people throughout the surrounding region call it Mount Yahazu. It stands out prominently.” Its distinctive silhouette can be seen from the Nōbi Plain.
Mount Koka is one of the 100 Famous Mountains of Gifu and lies within the Oku-Nagara Prefectural Natural Park designated by Gifu Prefecture.
Mount Koka rises between the Horado and Itadori areas and the border with Gujo City. It reaches an elevation of 1,224.2 meters. The historical text Nōyō Shiryaku describes Kōgadake as a particularly prominent mountain facing Mount Shirodake in Itadori, with a distant outline resembling a notched arrow. For this reason, surrounding communities also called it Mount Yahazu.
Mount Fūga, at 1,162.6 meters, rises to the southeast, while Mount Imabuchigatake, at 1,048.4 meters, stands to the south. The Nagara River flows southward east of these three mountains, the Nabi River runs to the north, and the Itadori River, a tributary of the Nagara River, flows along the western and southern sides. The area enclosed by these three rivers developed into a sacred mountain region in ancient times, with Mount Koka as its principal peak.
According to the founding legend, during the Reiki era (715–717), a monster resembling a bull in appearance and cry lived on Mount Fukube, now known as Mount Fūga, and harmed the villagers.
In 717, Fujiwara no Takamitsu was dispatched by imperial order to defeat the monster. At the foot of Mount Koka, he enshrined several deities, including Kuni-no-Tokotachi-no-Mikoto and Kuni-no-Satsuchi-no-Mikoto, and received their divine protection. After defeating the monster, he found that its vengeful spirit continued to appear. He then enshrined Kokūzō Bosatsu, a bodhisattva associated with wisdom and memory, and finally succeeded in subduing it with the deity’s protection.
Following these events, Takamitsu established six shrines at locations associated with the defeat of the monster. These are now identified as Kōga Shrine, Hongū Shrine and Shingū Shrine in Gujo City, Hoshinomiya Shrine in Minami, and Taki Shrine and Kinmine Shrine in Mino City.
During the late medieval period, Jōdo Shinshū Buddhism spread through the Nagara River basin, while Zen Buddhism became widespread along the Itadori River. As these traditions developed, Kōga-san worship gradually declined.
In the early modern period, however, a pilgrimage tradition involving visits to all six shrines took shape, and the mountain once again attracted widespread devotion among ordinary people.
A stone monument at the summit bears the inscription “Kokūzō Bosatsu” and the date 1841. Enkū also undertook extensive spiritual training at the foot of Mount Koka, leaving calligraphy and Buddhist images at places including Kōga Shrine and Hoshinomiya Shrine.
The Kōga Highway was an important historic route connecting settlements along the Nagara and Itadori rivers with the sacred mountain. It branched off from the Gujo Highway at Kamikōchi Village, now part of Mino City, where a river port served boats traveling along the Nagara River.
The route followed the Itadori River upstream before branching along the Kōga River from Abe Village and entering the mountains. From Kōga Shrine, it continued toward the summits of Mount Koka and Mount Fūga.
The Shōho-era provincial map depicts another route running upstream along the western bank of the Nagara River from Kamikōchi Village, passing through Sayo Village and crossing the river near its junction with the Itadori River to Tachibana Village on the opposite bank. It then continued through villages along the western bank of the Itadori River, including Nagase, Katachi, Warabi, and Ueno, before reaching Otogari Village.
These roads were used to transport local products from settlements in the upper Itadori River valley. As the port at Kamikōchi developed, the routes became connected as a larger highway network. They were subsequently used by pilgrims visiting the six shrines associated with Mount Koka.
The path from Horado to Mount Koka follows the Kōga River, a tributary of the Itadori River. It served both as a trading route for Kōga Village and as a trail for mountain ascetics.
After entering the mountains from Kōga Shrine, hikers encounter a stone known as the Chikaraishi, or “Power Stone.” Local tradition holds that placing a small stone on it brings strength and helps ensure a safe climb.
Farther along is a small waterfall known as the Koritori-ba, where ascetics are said to have purified themselves with water. The path then reaches a cave where Fudō Myōō, a Buddhist deity associated with protection and spiritual discipline, was enshrined until the early Meiji period. A legend about the immortal nun Yao Bikuni is also associated with the area.
Higher up, the path divides. One branch leads to the summit of Mount Koka, while the other passes through Minechigo Shrine and continues to Mount Fūga.
Stone statues of Batō Kannon, the Buddhist deity of compassion associated with horses, and roadside guardian deities can still be found along the historic highway in areas including Amage and Warabi in present-day Mino City, as well as Kosaka, Ōno, Ichiba, and Tsūgenji in the former Horado area. These monuments reflect the prayers of travelers for safety on the mountain roads.
Mount Koka and its surrounding shrines preserve numerous cultural treasures. Kōga Shrine houses Buddhist sculptures, including a bodhisattva statue dated to 1124 and an image of Dainichi Nyorai, the cosmic Buddha central to Esoteric Buddhism.
Shingū Shrine preserves wooden sculptures carved from single blocks of timber, including a statue of the Eleven-Headed Kannon and a statue of Jizō Bosatsu. These works reflect the area’s long-standing religious traditions.
The mountain region is believed to have developed into a sacred center for practitioners of mountain religion by the late Heian period (794–1185).
Kōga Forest Park occupies a wooded area extending from Kōga Shrine toward the foot of Mount Koka. The park also serves as a trailhead for mountain hikes.
Cherry blossoms bloom in spring, and seasonal flowers bring color to the landscape throughout the year. With its peaceful forest setting, the park is also an appealing place for picnics and enjoying nature.
Mount Koka, Mount Fūga, and Mount Imabuchigatake are collectively known as the Three Mountains of Kōga. All three are associated with Kōga-san worship, with Mount Koka recognized as the principal peak of this sacred mountain group.
Mount Koka lies east of the main ridge of the Etsumi Mountains, which extends along the border between Fukui and Gifu prefectures. The mountain is surrounded by the Nagara and Itadori rivers, and Misaka Pass lies along its ridge.
At the pass stands Minechigo Shrine. According to local tradition, the shrine commemorates the spirit of a young child who was abducted by a monster and brought from the imperial capital of Kyoto to this region.
The most commonly used hiking route starts at Kōga Shrine, passes through Misaka Pass, and continues to the summit. Fresh green foliage is at its best around mid-May, while autumn colors typically peak around mid-November.
Another approach is possible from the direction of Mount Fūga via the Naka-Mino Forest Road. At the summit, hikers will find a first-order triangulation point and a Buddhist memorial monument inscribed with the year 1841.
On clear days, the summit offers views of Mount Nōgōhakusan, Mount Hakusan, Mount Norikura, and Mount Ontake, along with the surrounding mountain ranges.
A maintained trail begins near Kōga Shrine and follows the Miyashita Forest Road toward Kōga Forest Park. This route is considered relatively easy in terms of both technical difficulty and physical exertion.
From Misaka Pass, hikers follow the mountain ridge to reach the summit. The annual Kōga Hiking Festival is held on April 29.
The route from the Takahata Onsen area is less frequently used. Sections have faint or disappearing trail markings, making navigation more difficult than on the main route from Kōga Shrine.
The Six Shrines of Mount Koka are a group of six shrines traditionally believed to have been founded by Fujiwara no Takamitsu. They are located around the mountain and are linked by the area’s legends of defeating a monster.
In the past, pilgrims undertook a demanding circuit of all six shrines, traveling along mountain ridges and attempting to complete the journey in a single day.
Kōga Shrine: Seki City, Gifu Prefecture.
Nabi Shingū Shrine: Gujo City, Gifu Prefecture.
Hongū Shrine: Gujo City, Gifu Prefecture.
Hoshinomiya Shrine: Gujo City, Gifu Prefecture.
Taki Shrine: Mino City, Gifu Prefecture.
Kinmine Shrine: Mino City, Gifu Prefecture.