Mount Koma is a small but picturesque mountain straddling Hiratsuka City and Oiso Town in Kanagawa Prefecture. Located at the eastern edge of the Oiso Hills, it stands 168 meters above sea level and is known for its rich natural environment and beautiful woodland scenery.
The mountain is covered with extensive natural broadleaf forests, creating a peaceful landscape that changes with the seasons. Its outstanding natural beauty has earned it a place on the list of Japan’s 100 Natural Sites Worth Preserving in the 21st Century. Despite its modest elevation, Mount Koma offers visitors an enjoyable opportunity to experience the countryside and explore the natural surroundings of the Shonan region.
Mount Koma has a long history closely connected with the spread of culture from the Korean Peninsula to Japan. In the past, a Buddhist temple called Korai-ji stood on this mountain, and the area was known as Koraiji-san or simply Mount Koma.
Korai-ji was associated with Koma Wakko, a historical figure who came to Japan from the ancient Korean kingdom of Goguryeo (Koguryo). The temple is said to have been established to honor him, reflecting the historical connections between the region and people who migrated from the Korean Peninsula.
During the Muromachi period (1336–1573), Korai-ji suffered repeated damage caused by warfare. The temple experienced a period of serious decline and was reportedly brought close to complete abandonment.
Its fortunes improved during the Edo period (1603–1868), when the Tokugawa family placed the temple under the jurisdiction of Kan’ei-ji Temple in Ueno, Edo (present-day Tokyo). The establishment of a Toshogu Shrine on the temple grounds also helped restore its prominence, and Korai-ji once again flourished as an important religious institution.
However, the beginning of the Meiji period (1868–1912) brought another dramatic change. Under the government’s policy of separating Buddhism and Shinto and suppressing Buddhist institutions, known as haibutsu kishaku, Korai-ji was abolished. Its temple buildings and other structures were destroyed, leaving only the Koma Shrine.
This remaining shrine was subsequently renamed Takaku Shrine, which continues to be known by that name today. Its history preserves an important connection to the religious and cultural heritage of Mount Koma.
The name Mount Koma is generally believed to have developed from its former name, Koraiji-san, which referred to the Buddhist temple that once stood on the mountain. However, there are also different theories regarding the origin of the name.
One theory suggests that refugees from the ancient Korean kingdom of Goguryeo, which fell in the 7th century, settled in this area and established a temple. The mountain subsequently became known as Mount Koma, reflecting the origins of these early settlers.
Several local historical clues are associated with this theory. Decorative objects discovered in nearby ancient burial mounds have been cited as evidence of cultural connections with the Korean Peninsula. The place name Toga-hara, written with the characters for Tang and plain and located south of the mountain, is another geographical clue often mentioned in connection with the area’s historical background.
Mount Koma is also associated with the legend of Toragozen, a woman who appears in the historical epic known as the Soga Monogatari (The Tale of the Soga Brothers). According to local tradition, she lived in this area and spent her later years near Korai-ji Temple.
These historical accounts and legends add a cultural dimension to the mountain, making it an interesting destination not only for nature lovers but also for visitors interested in the history of the Shonan region.
Mount Koma is designated as the Koma-yama Prefectural Forest, an extensive natural area covering approximately 29 hectares. The woodland is home to around 500 species of plants, providing a valuable environment for nature observation and outdoor recreation.
The forest’s broadleaf trees create an appealing landscape throughout the year. Visitors can enjoy the changing scenery as fresh greenery appears in spring, the woodland becomes lush in summer, and autumn brings seasonal colors. The variety of plant life also makes the area suitable for observing local vegetation and experiencing the natural environment of the Oiso Hills.
One of the popular hiking routes connects Shonan-daira (Mount Awatari) with Mount Koma. This relatively easy trail is well known among local residents and is suitable for visitors who want to enjoy a short walk in nature without undertaking a demanding mountain hike.
The walk from Shonan-daira to the summit of Mount Koma takes approximately 30 minutes. Along the way, hikers can enjoy the peaceful woodland atmosphere and the natural scenery of the surrounding hills.
Another recommended route begins at Takaku Shrine, the historic shrine associated with the former Korai-ji Temple. From there, hikers can proceed to the summit of Mount Koma, continue toward Shonan-daira, and eventually descend in the direction of Oiso.
This route allows visitors to combine a visit to a historic religious site with a relaxing walk through the mountain forest. It is an appealing option for those who wish to experience both the cultural heritage and natural beauty of the area.
Benches and tables are provided along the walking paths, allowing hikers to take breaks, relax, and enjoy the surrounding scenery at their own pace.
Mount Koma offers a pleasant combination of natural beauty, historical heritage, and accessible hiking trails. Its 168-meter elevation makes it an approachable destination for casual walkers, while its approximately 29-hectare woodland provides plenty of opportunities to appreciate the region’s natural environment.
Visitors can explore the forest, observe its diverse plant life, follow trails connecting Takaku Shrine and Shonan-daira, and discover stories associated with the ancient Korean immigrants who helped shape the area’s cultural history.
For travelers exploring Hiratsuka, Oiso, and the wider Shonan region, Mount Koma is a rewarding place to slow down and enjoy a quieter side of Kanagawa Prefecture, away from the busy coastal attractions.