Oirase Stream is one of Japan’s most spectacular natural landscapes, flowing through Towada-Hachimantai National Park in Towada City, Aomori Prefecture. The stream is the only river that flows out of Lake Towada and winds for approximately 14 kilometers through a lush mountain valley.
With crystal-clear water, moss-covered rocks, dramatic waterfalls, and dense riverside forests, Oirase Stream offers a landscape that changes beautifully with the seasons. It has been designated as both a Special Place of Scenic Beauty and a Natural Monument of Japan, and is widely regarded as one of the country’s finest destinations for experiencing pristine natural scenery.
Fresh green leaves in spring, cool forests in summer, brilliant autumn foliage, and snow-covered scenery in winter each give Oirase a completely different character.
The landscape of Oirase Stream was shaped by the geological history of Lake Towada, a double-caldera volcanic lake. Geological changes associated with the lake and the surrounding Towada volcano created the valley through which the Oirase River flows today.
Along the stream, visitors can see steep cliffs, rushing rapids, pools, and numerous waterfalls. The constantly changing flow of water creates a remarkable variety of scenery within a relatively short distance.
The riverside forest is dominated by trees such as Japanese horse chestnut, Japanese wingnut, and katsura. Mosses and ferns cover the forest floor, rocks, and fallen trees, creating an intensely green landscape.
As sunlight filters through the trees and reflects on the clear water, the stream seems to glow from within. The combination of water, forest, rocks, and light is one of the defining features of Oirase.
One of Oirase Stream’s greatest attractions is that its natural beauty can be enjoyed without undertaking a difficult mountain climb. A well-maintained walking route follows the stream, while a road runs alongside much of the valley.
The popular route between Ne-no-kuchi and Yakeyama covers approximately 14 kilometers. Along the way, visitors encounter waterfalls, rapids, rock formations, and particularly scenic sections of the stream.
Travelers can choose how much of the route they want to explore according to their available time and physical condition. Walking even a short section provides an opportunity to experience the sound of rushing water and the atmosphere of the forest.
Choshi Otaki Waterfall is one of the most impressive waterfalls along the stream. Approximately 7 meters high and 20 meters wide, it is remarkable for its broad curtain of water and powerful flow. The sound of the waterfall and the spray rising from the pool below create an unforgettable atmosphere.
Kumoi Falls is another iconic waterfall. The water descends in three stages from a forested cliff, creating a beautiful 20-meter cascade. Surrounded by dense woodland, the waterfall has a mysterious and dramatic appearance.
Asyura no Nagare, or the Asyura Rapids, is one of the most famous sections of Oirase Stream. The water rushes over rocks in a series of powerful currents, creating an almost living, constantly moving landscape.
Ishigedo is another interesting spot along the trail. The area is associated with a local legend about a female bandit named Omatsu, and a distinctive rock shelter supported by a large katsura tree adds to its atmosphere.
Oirase Stream is a year-round destination, with each season offering a different landscape and experience.
Spring brings new leaves and fresh vegetation to the forest. From around mid-May to mid-June, the young greenery reaches its most beautiful stage, creating a bright and refreshing atmosphere along the stream.
Sunlight filtering through the new leaves reflects on the water, while the sound of the flowing stream makes a spring walk especially peaceful.
During summer, the dense forest forms a natural canopy over the stream. The shade keeps the walking paths relatively cool, while the sound of running water provides a refreshing escape from the heat.
For travelers looking for a peaceful place to enjoy Japan’s summer landscape, Oirase is an ideal destination.
Autumn is one of the most popular seasons to visit Oirase. From around mid- to late October, the surrounding trees turn vivid shades of red, orange, and yellow.
The colorful foliage is reflected in the clear water, creating a spectacular contrast between the autumn forest and the dark green moss-covered rocks. During this period, visitors arrive from all over Japan to enjoy the scenery.
In winter, Oirase takes on a completely different appearance. Snow covers the forest and rocks, while sections of the waterfalls may freeze into impressive icefalls.
The quietness of the snow-covered valley creates a mysterious atmosphere. Early in the morning, when mist and sunlight move through the trees, the scenery can appear almost dreamlike.
Oirase Stream is particularly famous for its abundant mosses. Around 300 species of moss are found in the area, covering rocks, fallen trees, tree trunks, and even structures along the trail with a soft green layer.
The humid environment created by the stream and surrounding forest provides ideal conditions for moss and other plants. Ferns and other moisture-loving species thrive alongside them, forming a richly layered ecosystem.
The forest is also home to a wide variety of birds and other wildlife. Visitors may encounter species such as the Japanese wagtail, brown dipper, crested kingfisher, and ruddy kingfisher.
The soundscape of Oirase is an important part of the experience. Flowing water, birdsong, rustling leaves, and the movement of wind through the trees combine to create an atmosphere that encourages visitors to slow down and simply listen.
Oirase Stream has long been recognized for its exceptional scenic value. In 1928, Oirase and Lake Towada were designated as Places of Scenic Beauty and Natural Monuments. In 1952, these designations were elevated to Special Places of Scenic Beauty and Special Natural Monuments.
Since the Meiji period, efforts have been made to preserve the area’s natural landscape. Today, conservation remains an important part of managing Oirase so that future generations can continue to experience its forests, waterfalls, and clear water.
Water levels are also managed at the Ne-no-kuchi water gate. Controlled releases known as tourism water releases help maintain an attractive flow in the stream while supporting the landscape that visitors come to enjoy.
Choshi Otaki is one of the signature attractions of Oirase Stream. It is approximately 7 meters high and 20 meters wide, making it one of the most visually impressive waterfalls in the valley despite its relatively modest height.
Rather than falling from great heights, the water spreads broadly across the rocks, producing a powerful and continuous flow. The large volume of water creates a deep roaring sound as it reaches the pool below, while fine spray fills the air around the waterfall.
When sunlight enters the spray, shafts of light can appear among the surrounding trees, creating an almost magical scene.
Moss-covered rocks and dense vegetation surround the waterfall, allowing visitors to experience the distinctive atmosphere of Oirase’s forest ecosystem at close range.
Kumoi Falls is located in the middle section of Oirase Stream and is one of the valley’s most impressive waterfalls. Water descends in three stages from a forest-covered cliff, creating a cascade approximately 20 meters high.
The abundant flow of water gives the waterfall a powerful presence, while the surrounding primeval-looking forest creates a secluded and mysterious atmosphere.
Among the many waterfalls scattered along Oirase Stream, Kumoi Falls is particularly worth stopping to admire and photograph.
Oirase Stream is accessible via National Route 102, which runs through the area. From the Ne-no-kuchi bus stop on the shore of Lake Towada, visitors can travel toward Yakeyama by bus or car, while sections of the stream can also be explored on foot.
Because Oirase is particularly popular during the spring greenery and autumn foliage seasons, roads and parking areas can become busy. Visiting early in the morning is recommended for travelers who want to enjoy a quieter atmosphere.
The Oirase Stream Museum is located along the route and provides information about the area’s natural environment, geology, plants, and wildlife. Visiting the museum can help travelers better understand the landscape they are about to explore.
Before traveling, it is also useful to check current transportation conditions, seasonal access information, weather, and trail conditions, particularly during winter.
Oirase Stream is a place where water, forest, light, and changing seasons come together to create one of Japan’s most beautiful natural landscapes.
Every season offers something different. In spring, fresh leaves brighten the forest. In summer, the shaded valley provides a refreshing retreat. In autumn, brilliant foliage surrounds the stream, while winter transforms the waterfalls and forest into a quiet world of snow and ice.
The experience is not simply about sightseeing. Walking beside the stream, listening to the waterfalls, feeling the cool forest air, and observing moss-covered rocks and trees allows visitors to experience nature at a much slower pace.
For travelers looking to discover the quieter and more pristine side of Japan, Oirase Stream is an unforgettable destination in northern Aomori Prefecture. Its clear water, dramatic waterfalls, ancient-looking forests, and peaceful walking trails offer a memorable encounter with the natural beauty of Japan.
Free of charge
80 min. by bus from Hachinohe Stn.
120 min. by bus from Aomori Stn.