The formation of Kiyotsu Gorge

16 million years ago,
the eruption of a submarine volcano covered the ocean floor in a thick layer of volcanic ash. Via a chemical transformation,
this ash turned green in color, forming a type of rock known as green tuff.

5 million years ago,
magma flooded the space under this layer of green tuff, cooling and hardening to create porphyritic rock.
As it cooled, it contracted, resulting in structures called columnar jointing.

Later, during a period of significant surface layer activity, the seabed rose and became dry land. It continued to be forced upward, forming mountains.

At the same time, a river (the Kiyotsu River) wore into the mountains, forming a valley.

As the mountains were worn away,
the porphyritic columnar jointing underground was revealed at the bottom of the valley.
The valley grew even deep, resulting in what we know as Kiyotsu Gorge today.

About columnar jointing


Columnar jointing consists of four- to six-sided natural rock pillars formed when magma cools and hardens.

The rocky walls of Kiyotsu Gorge are made up of columnar joints jumbled together (like bundles of hexagonal pencils). As they are not made up of single, large slabs of stone, while the rock itself is hard, the walls are fragile and can collapse relatively easily.

Similar columnar jointing can also be seen in Akiyamago in adjoining Tsunan Town. On Mt. Yamabushi, also in Tsunan Town, you can see horizontal columnar jointing.

Tuff・・・Tuff forms when volcanic ash solidifies into rock.

Porphyrite・・・Porphyritic rock is a type of volcanic rock formed when magma cools and hardens. Andesite and basalt are formed via similar processes.

The history of Kiyotsu Gorge

The presence of hot springs in the area was already known some 300 years ago.

Starting from around that time, there was talk of developing the hot springs for baths,
but due to the terrain and a large number of other challenges, no progress was made on this front for many years. Finally, in 1862, a hot spring spa was built by local residents, which still exists to this day.

In 1941, the gorge was designated a National Place of Scenic Beauty and Natural Monument due to its beauty and magnificent columnar jointing.
In 1949, the gorge was designated a part of Joshin'etsu-kogen National Park, after which time it became a renowned sightseeing destination.
A hot spring district was also built in the area.

In February 1984, a large snow avalanche directly struck a section of the hot spring district, killing and wounding several people.
The current Kiyotsukan inn was rebuilt after that time.

Building the Kiyotsu Gorge Tunnel

ⅤA trail following the Kiyotsu River from Kiyotsukyo Onsen passing through Yagisawa made it possible for visitors to enter and travel through the gorge, but avalanches and lingering snows would block it in early spring, and large and small falling rocks as well as landslides were frequent occurrences, making the path extremely dangerous.

In July 1988, falling rocks struck a man on the head, resulting in his death. Thereater, it was determined that safe passage could not be guaranteed to visitors and usage of the trail, and consequently entry into the gorge, was prohibited without exception. Accordingly, it became impossible to enter the depths of the gorge from the hot spring district and see the sheer cliffs found there, which boast the most spectacular and beautiful columnar jointing in the gorge.

Many locals and visiting tourists requested that it be made possible for them to view the gorge’s beauty, and the Environment Agency (in charge of National Parks), the Agency for Cultural Affairs (in charge of Natural Monuments), the Niigata Prefectural government, Nakasato Village (now a part of Tokamachi City), and other relevant agencies began investing the matter.

The following determinations were made:

  1. Reopening the closed trail was not a possibility.

  2. The collapse-prone rock walls made the creation of a safe trail extremely difficult.

  3. The construction of a large-scale artificial structure which would damage scenic views would not be permitted in a National Park.

  4. The purpose of Japan’s National Parks is for them to be used by residents as widely as possible, and, as the gorge was also a tourism resource, leaving things as they were was not an option.

  5. Based on the above, the decision was made to build a pedestrian tunnel in place of the old trail to provide safe passage without damaging the gorge’s scenery.
    Subsidiary aid was provided by Niigata Prefecture, and Nakasato Village served as the implementing body. Total construct costs came to approximately two billion yen. Construction began in 1992 and the tunnel was opened on October 1, 1996.

For the first time in eight years, people were again able to see the gorge’s beauty, albeit only a part of it. The trailalong the river remains closed to this day.

There is now, the tunnel makes it possible for visitors to safely enjoy the gorge without worrying about what’s above (the weather and falling rocks), or what’s below (steps, uneven terrain, etc.).

The tunnel is also open to stroller and wheelchair users. Because of these reasons, the tunnel has been particularly praised by group tour operators and families with small children or senior members, etc. who are not able to walk a rough nature trail. In addition, people are beginning to realize that, thanks to the tunnel, this is one of only a very few places where you can easily enjoy deep mountain snowscapes in the middle of winter.

Kiyotsu Gorge Tunnel

After an incident involving falling rocks in 1988, the Kiyotsu Gorge valley was closed to the public. The Kiyotsu Gorge Tunnel was opened in October 1996 to make it possible for visitors to enjoy the magnificent natural beauty of the area in a safer and more secure way. The structure was restored in 2018 for the Echigo Tsumari Art Trienniale as an artwork called “Tunnel of Light” by Ma Yansong / MAD Architects.

The tunnel is 750 meters long in total. From the three viewing locations along the tunnel as well as the Panorama Station at its end, visitors can take in the fantastic beauty of the gorge. You can really take in the scenery here. The most impressive spot here is the panorama station at the end of the tunnel, where the scenery is mirrored back on a reflecting pool in a beautiful art space. There are also delightful exhibits throughout the tunnel for visitors to enjoy which provide information on the gorge’s seasons, plant and animal life, and how it came to be formed.

Four seasons of Kiyotsu Gorge


Early May – late June The best time for fresh verdure and river beauty


Snowmelt fills the river and, with the onset of the late spring, new greenery bursts forth all at once, instantaneously filling the previously drab landscape with color. Lingering patches of hardened snow formed by the repeated accumulations of avalanches during the winter can be seen here and there on the gorge bottom.

Patches of snow also hang over portions of the river, but the river continues to flow unabated underneath and never becomes blocked during this time. The snows melt away on the ground, sometimes leaving natural bridges of snow over the river hollowed out by the water flowing underneath. If you are very lucky, you just might get to see a mass of this snow collapsing into the river with a loud splash.

Via avalanches and winds, the surfaces of any lingering patches of snow accumulates dried leaves and dirt from the surrounding forest, turning them a brown color. Snow can linger here up to around June. The first new leaves begin appearing from about the end of April. The colors of the leaves differ subtly depending on the species, resulting in beautiful scenery that is a match for the area’s spectacular fall foliage. Meanwhile, on the banks of the river where the snows have only just melted, lovely early spring flowers come into bloom.


Early July – mid-October River fun


Filled with rich greenery and the murmurs of the pure river, the gorge enters tourist season.

Many make their way to the riverbank and dip their toes in its icy waters.

Outside, temperatures often exceed 30° C, but inside the Kiyotsu Gorge Tunnel, it stays around 21 to 24° C and can even

feel chilly.

No sunlight penetrates into the tunnel, and a constant refreshing breeze blows off the river, providing it with natural

air conditioning.

However, the moisture-rich river air cools and condenses inside the tunnel, resulting in high humidity (over 90%), and

extreme differences in temperature inside and outside the tunnel persist throughout the summer.


Late October – mid-November The fall foliage season


No paints on Earth can fully express the stunning beauty created by the interweaving of the stark bare rock walls and

vivid autumn foliage induced by the gorge’s extreme temperature differentials.

Fall is the season when Kiyotsu Gorge is at its busiest, and extreme crowding and congestion can be expected from

mid-October to late November.

The best time to see the area’s fall foliage starts from around the middle of October and lasts until the end of October

to the start of November.

The gorge’s green foliage begins to grow pale, brilliant yellows start to stand out, and eventually almost all of the trees

are covered in gold, but patches of crimson can also be seen here and there.

Due to the gorge’s spring avalanches and climatic variations, each year the conditions of the trees is different,

resulting in different color patterns every fall.

The leaves begin to fall off in mid-November in preparation for winter.


Mid-November – late May Winter snowscapes


Even for Niigata, a place known for snow, Kiyotsu Gorge experiences heavy snowfall.

The contrast between the roughly carved columnar jointing of the gorge’s cliffs and the white of the snow resembles an

ink painting.

In most years, the first snow of the season falls in late November. Most of the time, this snow melts away and does not


The true snows begin to fall and accumulate on the ground in mid-December.

The snow is powdery but abundant, and more than a meter can pile up in a single day.

Snow removal ensures that passage in and out of the area is still possible, but walls of snow greater than two meters high

enclose roads on either side, and small avalanches blocking cliffside roads are a frequent occurrence.

Note: The gorge tunnel may temporarily close in winter due to the snow conditions.