Oni no Shitaburui is a spectacular gorge in Okuizumo Town, Nita District, Shimane Prefecture. It was formed over an immense period of time as the Omaki River, a tributary of the Hii River, gradually eroded the surrounding granite.
Stretching for approximately 2 to 3 kilometers, the gorge features towering cliffs, enormous granite boulders, unusual rock formations, and a clear mountain stream. The dramatic scenery has made it one of the most distinctive natural attractions in the Chugoku region.
In 1927, the area was designated a Place of Scenic Beauty and Natural Monument of Japan in recognition of both its scientific value and exceptional landscape. In 1964, it was also designated as the Oni no Shitaburui Prefectural Natural Park.
A walking trail has been developed along the gorge, allowing visitors to observe the rocks, natural potholes, cliffs, and flowing water at close range. Much of the trail has been designed with barrier-free access, making it possible for children, older visitors, and wheelchair users to enjoy the scenery.
The unusual name Oni no Shitaburui is connected to an ancient legend from the Izumo region.
According to the Izumo no Kuni Fudoki, a beautiful goddess named Tamahime-no-Mikoto was repeatedly visited at night by a wani that longed for her. In ancient Japanese texts, the word “wani” is generally understood to have referred to a shark or another large aquatic creature.
The goddess disliked the wani’s advances and blocked the river with a huge rock. Even then, the creature continued to yearn for her. The expression describing the wani’s longing is said to have eventually developed into the name “Oni no Shitaburui.”
Another interpretation suggests that the name refers to a gorge so frightening and rugged that it could make an ogre’s tongue tremble. Standing among the enormous rocks and roaring water, it is easy to understand how such a dramatic name became associated with the landscape.
The greatest attraction of Oni no Shitaburui is its extraordinary geological landscape, created by natural forces over an enormous span of time.
The area is composed of biotite granite formed approximately 50 million years ago deep beneath the Earth’s surface. Later, tectonic movements brought the granite closer to the surface, where the powerful current of the Omaki River gradually eroded it and created the V-shaped gorge visible today.
The granite contains numerous natural fractures known as joints. Water erosion and weathering gradually weakened the rock along these joints, causing enormous sections of granite to break away and form the bizarre rocks and cliffs seen throughout the gorge.
Some cliffs reach approximately 80 meters in height, while enormous boulders measuring more than 10 meters in diameter can be found along the gorge. The clear stream flowing between the rocks adds another beautiful element to the dramatic scenery.
In spring, the gorge is surrounded by vibrant new foliage. Broad-leaved trees such as Japanese beech, hornbeam, and maple create a refreshing contrast with the clear stream.
A walk through the gorge during this season offers fresh mountain air and a wonderful sense of nature coming back to life.
In summer, the shade of the trees and the cool flowing water make Oni no Shitaburui a pleasant place to escape the heat. The sound of the stream and the cool air within the deep gorge create a refreshing atmosphere.
Visitors may also encounter birds associated with clear mountain streams, including crested kingfishers and brown dippers.
Autumn is one of the most popular seasons to visit. The trees surrounding the gorge turn shades of red, orange, and yellow, creating a striking contrast with the enormous gray granite formations.
During the autumn foliage season, the gorge attracts many visitors and photographers and is recognized as one of the notable places in the Chugoku region for enjoying fall colors.
In winter, snow can transform the gorge into a remarkably quiet landscape. White snow covering the ground and pale granite cliffs creates an atmospheric scene that feels almost otherworldly.
Shito-iwa is one of the most famous rock formations in Oni no Shitaburui. A massive boulder appears to have been split cleanly in two, leading to the traditional story that an ogre used it to test the sharpness of its sword.
In reality, the rock split naturally along joints within the granite. Its remarkably straight surface, however, can look almost as though it had been deliberately cut.
Senjojiki is a huge rock with a broad, flat surface. Its name means roughly “a thousand tatami mats,” referring to its appearance as though countless traditional Japanese tatami mats had been laid across the rock.
The enormous flat surface is a natural joint plane in the granite and demonstrates the impressive scale of the geological forces that shaped the gorge.
Byobuiwa is a towering rock wall resembling a traditional Japanese folding screen. The cliff reveals how the river has gradually carved the granite over time.
Round depressions known as potholes can also be seen in the rocks. These were formed as small stones were repeatedly spun around by flowing water, gradually grinding circular holes into the bedrock.
Oten-gu Rock is an enormous cliff reaching approximately 80 meters in height. Its near-vertical rock face and clearly visible joints provide an impressive example of the geological processes that shaped Oni no Shitaburui.
Funaiwa and Tsurugi-iwa are unusual rocks that resemble a boat and a sword depending on the viewing angle. Their distinctive shapes are the result of natural erosion and weathering, creating landscapes that resemble works of natural art.
A bridge has been built over Tatami-iwa, allowing visitors to walk across the rock itself. Its remarkably flat surface may look artificially carved, but it too was formed through natural geological processes.
Hando-iwa is a fascinating rock that resembles a traditional water jar, or “hando,” standing in an unusual position on top of a larger boulder.
It is thought to have originally been part of a single larger rock. Erosion around it gradually exposed the distinctive shape seen today.
Oni no Rakurui-iwa is a strangely shaped rock that can appear to resemble a human face. Two potholes on the rock look like tears, giving rise to its name, which means roughly “the ogre’s tearful rock.”
Ko-tengu Rock is another impressive cliff located near Oten-gu Rock. The exposed joints and traces of natural rockfall can be observed from close range, making this an especially interesting location for visitors fascinated by geology.
Amatsubo contains numerous potholes of different sizes. Although the area is no longer directly in the river’s main flow, the potholes provide evidence that the river once flowed at this elevation.
Eboshiiwa is a large angular boulder shaped somewhat like an eboshi, the traditional tall headwear once worn by members of Japan’s court and warrior classes. It was formed as granite broke into blocks and eventually fell toward the bottom of the valley.
Oni no Shitaburui is particularly notable for the many river potholes found throughout the gorge. These are circular depressions formed when small stones become trapped in swirling water and repeatedly rotate against the bedrock.
During periods of high water, powerful currents and whirlpools can cause stones to spin with considerable force. Over extremely long periods, this process gradually excavates circular holes in the granite.
Some potholes can reach more than one meter in diameter. One particularly notable group is known as Amatsubo.
These formations, created by nature over tens or even hundreds of thousands of years, can be regarded as works of art created by the Earth itself.
Completed in 2013, the Shitburu “Koi” Suspension Bridge is approximately 45 meters above the ground and 160 meters long.
From the bridge, visitors can look out across the gorge from above and experience the dramatic landscape almost as if taking a walk through the air. The view is particularly impressive during the autumn foliage season.
The word “Koi” means “love” or “romance” in Japanese. The bridge’s name was inspired by the romantic legend associated with Oni no Shitaburui, making it a popular destination for couples and married visitors as well.
In 1930, the famous Japanese poets Akiko Yosano and Tekkan Yosano visited Oni no Shitaburui. Inspired by the grandeur of the landscape, the couple composed numerous poems about the area.
Their works were later included in the poetry collection Heiunsho, showing that the beauty of Oni no Shitaburui has inspired not only travelers but also important figures in Japanese literature.
The walking trails at Oni no Shitaburui have been developed with barrier-free access, and wheelchair users can access much of the route.
The trail system extends between Une Parking Area and Shimotakao Parking Area, allowing families with young children and older visitors to enjoy the scenery more comfortably.
This accessibility makes Oni no Shitaburui an unusual natural attraction where visitors can enjoy spectacular geological scenery without requiring a strenuous mountain hike.
Oni no Shitaburui is approximately 10 minutes by car from JR Izumo-Minari Station. Free parking is available near the entrance.
The walking trail takes approximately 60 minutes for a round trip. Visitors who want to stop frequently for photographs and enjoy the scenery at a leisurely pace should allow approximately 1.5 to 2 hours.
Oni no Shitaburui is a spectacular gorge shaped by natural forces over an immense span of time. Giant granite boulders, unusual rock formations, river potholes, towering cliffs, and clear mountain water combine to create a landscape worthy of its designation as a National Place of Scenic Beauty and Natural Monument.
The gorge is also deeply connected with Japanese mythology, local legends, and literature, allowing visitors to experience much more than scenery alone. Each season brings a different atmosphere, from spring greenery and refreshing summer streams to brilliant autumn foliage and tranquil winter snow.
With its accessible walking trails and dramatic natural scenery, the Oni no Shitaburui Nature Observation Trail is an excellent destination for travelers exploring Okuizumo and looking to experience the geological and cultural heritage of rural Japan.