Oni no Shitaburui Gorge is a spectacular natural valley in Okuizumo Town, Shimane Prefecture. Located along the upper reaches of the Omamaki River, a tributary of the Hii River, it is one of the region’s most impressive scenic destinations.
Its official name is Onizaburui, and the gorge was designated a National Place of Scenic Beauty and Natural Monument in 1927. In 1964, it was also designated as a Prefectural Natural Park, further recognizing its outstanding natural environment.
The V-shaped gorge extends for approximately 2 to 3 kilometers and was formed over an immense period of time through the erosive power of flowing water. Massive boulders, strangely shaped granite formations, and clear mountain streams combine to create a dramatic landscape that conveys the power and mystery of nature.
The greatest attraction of Oni no Shitaburui Gorge is the extraordinary collection of strangely shaped rocks scattered throughout the valley.
The granite has been gradually carved by the river over countless years, producing formations that look almost like works of art created by nature itself.
Among the notable formations are the steep rock walls known as O-Tengu Rock and Ko-Tengu Rock, as well as broad rock surfaces called Senjojiki and Tatami Rock.
Other unusual formations include Hando Rock, Turtle Rock, Oni no Rakurui Rock, and Eboshiiwa Rock. Each has its own distinctive shape and story, giving visitors something new to discover as they walk through the gorge.
Numerous circular holes known as potholes can also be found in the riverbed and exposed rock surfaces. These formations were created as small stones were repeatedly spun around by the force of flowing water, gradually grinding away the granite.
Some potholes measure more than 1 meter in diameter. They provide a fascinating record of the immense power of water and the long geological history of the gorge.
The unusual name Oni no Shitaburui is connected with an ancient story recorded in the Izumo Fudoki, an eighth-century record describing the geography, culture, and traditions of the ancient Izumo region.
According to the story, a creature known as a wani fell in love with the beautiful goddess Tamahime-no-Mikoto. In ancient Japanese usage, “wani” can refer to a large aquatic creature, traditionally interpreted in this story as a shark.
The expression describing the wani’s longing for the goddess is said to have developed into the name of the gorge. Another local tradition tells of the creature repeatedly trying to cross the river to reach the goddess but being prevented from doing so.
These legends add a mysterious atmosphere to the dramatic landscape, connecting the rocks and river with the ancient mythology of Izumo.
The landscape of Oni no Shitaburui is the result of geological processes that took place over an enormous span of time. Granite formed deep underground approximately 50 million years ago was eventually exposed at the surface through movements of the Earth’s crust.
Afterward, weathering and erosion gradually transformed the granite. Natural fractures known as joints developed within the rock, and sections of granite were progressively broken down and carried away along these lines of weakness.
The fast-flowing Omamaki River continued to cut into the exposed granite, eventually creating the distinctive V-shaped valley seen today. Huge rocks fell into the riverbed, where the current carved around them, creating rapids, pools, and unusual rock formations.
The result is a landscape that vividly demonstrates the power of water and geological change over immense periods of time.
Oni no Shitaburui Gorge offers a different atmosphere throughout the year. Broadleaf forests, including Japanese beech and maple trees, cover the surrounding mountains and provide a rich natural setting.
In spring, fresh young leaves emerge across the mountains, creating a bright and refreshing landscape filled with new life.
During summer, the clear stream and abundant shade provide a naturally cool environment. The sound of flowing water and the surrounding greenery make the gorge an enjoyable place to escape the heat.
Autumn is one of the most popular seasons to visit. The surrounding trees turn brilliant shades of red and yellow, creating a striking contrast with the dark rocks and clear water of the gorge.
In winter, snow can cover the gorge and surrounding forests, transforming the landscape into a quiet and almost otherworldly scene.
The clear stream is also home to fish such as Oikawa and Ugui, while birds including crested kingfishers and brown dippers can sometimes be observed. The gorge is therefore an excellent place for nature observation as well as sightseeing.
A walking trail of approximately 2 kilometers runs along the gorge, allowing visitors to explore the scenery at a relaxed pace. A round trip takes approximately 60 minutes.
The trail has been designed with barrier-free access in mind, making it possible for a wide range of visitors, including families with children and older travelers, to enjoy the gorge.
In 2013, the Shinobure no “Koi” Suspension Bridge was completed. The bridge stands approximately 45 meters above the ground and is about 160 meters long, providing a spectacular viewpoint over the gorge.
Looking down from the bridge offers an impressive sense of the valley’s scale, while the surrounding forests and rock formations create an especially beautiful scene during the autumn foliage season. The word “Koi,” meaning “love,” also gives the bridge an association with romance and wishes for successful relationships.
The beauty of Oni no Shitaburui has attracted artists and literary figures for generations. In particular, the celebrated poet couple Yosano Tekkan and Yosano Akiko visited the area in the early Showa period.
Poems inspired by their visit were later included in collections of their work, reflecting the ability of the gorge’s dramatic scenery to inspire literary creativity.
The spectacular V-shaped valley extending for more than 2 kilometers is the defining landscape of Oni no Shitaburui. The Omamaki River, a tributary of the Hii River, gradually carved through the granite over countless years.
Steep rock walls rise along both sides of the valley, while enormous boulders fill the riverbed below. The sight of the rushing stream winding between these rocks creates a powerful natural spectacle.
Throughout the gorge, visitors encounter rocks with remarkably unusual shapes. One famous example is Shitō Rock, a huge boulder that appears to have been split cleanly in two by a giant blade.
Senjojiki features a broad, flat expanse of rock resembling a floor covered with traditional tatami mats. Byobuiwa Rock has layers of rock that resemble a traditional Japanese folding screen, while O-Tengu Rock rises approximately 80 meters and creates one of the gorge’s most imposing views.
These formations were created by natural processes such as geological fracturing and erosion, making them remarkable examples of nature’s ability to shape solid rock over time.
The gorge contains countless potholes, or rounded hollows carved into the rock by flowing water and rotating stones.
Their sizes and shapes vary considerably, with some exceeding 1 meter in diameter. Some are also known as Ame-tsubo, or “rain pots.”
These formations provide evidence of the powerful currents that once flowed through the area and offer an opportunity to observe the geological history of the gorge firsthand.
The Shinobure no “Koi” Suspension Bridge, completed in 2013, is one of the most popular viewpoints in the gorge.
From the approximately 160-meter-long bridge, visitors can look across the valley and see the clear stream and giant rocks far below. During autumn, the vivid foliage creates a particularly beautiful contrast with the rugged landscape.
The Oni no Shitaburui Nature Observation Trail follows the gorge for approximately 2 kilometers. Along the route, visitors can observe giant boulders, unusual rock formations, clear mountain water, and the geological features created by erosion.
The trail has been designed with accessibility in mind, making it relatively easy to walk while still offering impressive views. Information boards along the route introduce plants and notable features, allowing visitors to learn more about the natural environment as they explore.
Shitō Rock is a huge boulder lying in the valley that appears to have been split into two pieces by a sharp blade.
The division was created naturally along a geological joint, demonstrating the immense forces that have shaped the surrounding granite. A local legend says that an oni, or demon, once tested the sharpness of its sword against the rock.
In recent years, the rock has also attracted attention because its distinctive shape evokes scenes from Japanese animation, making it a popular photo spot.
Senjojiki is a broad, flat expanse of rock that looks as though countless tatami mats have been laid across the valley.
The smooth surface was created when sections of granite broke away along natural joints. Its open character provides a refreshing contrast to the narrow sections of the gorge and offers visitors a chance to appreciate the scale of the surrounding landscape.
Byobuiwa Rock features distinctive curved surfaces and potholes carved by flowing water. The rock formations stretch across the landscape like a traditional Japanese folding screen.
One notable feature is a pothole known as Hime no Tōsen-ato, or “the Princess’s Fan-Throwing Mark,” which provides another fascinating reminder of the power of ancient water flows.
O-Tengu Rock rises approximately 80 meters and forms one of the most dramatic cliffs in Oni no Shitaburui. Its immense scale makes it one of the defining sights of the gorge.
Ko-Tengu Rock, meanwhile, provides an opportunity to observe geological joints and signs of rock collapse, offering a closer look at how the landscape was formed.
Funaiwa-Kenjō Rock has a curious shape that can resemble either a boat or a sword depending on the viewing angle. It is a fascinating example of how natural formations can stimulate the imagination.
At Tatami Rock, visitors can walk across sections of the flat rock surface created by natural joints, creating the feeling of standing on a stage formed entirely by nature.
Hando Rock is a particularly unusual formation, with a rock resembling a water jar delicately balanced above another section of stone.
Oni no Rakurui Rock, meaning “Demon’s Falling Tears Rock,” has potholes on both sides that make the formation resemble a human face. Its appearance evokes the image of an oni shedding tears.
At Ame-tsubo, visitors can see groups of potholes of various sizes. Even in places where water no longer flows, these hollows preserve evidence of the area’s geological past and the force of ancient currents.
Eboshiiwa Rock is characterized by its angular shape. It was formed as granite fractured into blocks and gradually collapsed. Its sharp outline can look almost as though it had been deliberately carved by human hands.
Oni no Shitaburui Gorge is a remarkable destination where giant rocks, clear mountain water, geological history, and ancient mythology come together.
The gorge has been shaped over immense periods of time by the forces of water, weathering, and geological change. Its dramatic rock formations and potholes are a vivid reminder of the power of nature, while the stories recorded in the Izumo Fudoki give the landscape an additional layer of cultural and mythical meaning.
Walking along the gorge and watching its scenery change with the seasons offers a chance to step away from everyday life and experience the natural beauty of Okuizumo at a leisurely pace.
For travelers visiting Okuizumo, Oni no Shitaburui Gorge is a memorable place to experience the extraordinary landscapes, ancient legends, and geological wonders of the Japanese mountains.