The power of nature 1：The story of the volcanos

The Nasu area showcases the remarkable interplay between its geological features, volcanic landscapes, and the local way of life. Shaped over millions of years by volcanic activity, this region tells a fascinating story of how nature has crafted its unique environment. Visitors can experience not only the majestic natural beauty of Nasu but also discover the rich history and culture of a community that has thrived alongside its volcanic neighbor. Here, you’ll find a deep connection between the land and its people, woven together through generations of coexistence with these powerful natural forces.

Nasu Onsen (Hotsprings), with a history of 1,400 years and offering six different types of spring waters still maintain its historical look.

The terrain in Nasu area is the result of volcanic activity that has occurred repeatedly over the past 1.6 million years. The Nasu mountain range is located at the southern end of the Nasu volcanic belt. It was formed by volcanic activity that began 500,000 years ago at Mt. Koshiasahi (1,835 m / 6,020ft.) The volcano erupted about 16,000 years ago and formed Mt. Chausu (1,915m / 6,282ft.). Mt. Chausu is the only active volcano in the Nasu mountain range today. The andesite that flowed from the crater of Mt. Chausu formed the summit. Volcanic vents are located near the summit on the western side of Mt. Chausu and around Sesshoseki (The killing stone) area on its southern foothills. It’s extremely hot sulfurous gas at around 90°C / 194℉ from vents. The biggest fissure near the summit is known as ‘Mugen Jigoku’ (The Inferno of No Escape).
Nasu Onsen offering a variety of hot springs, is derived from this active volcano. It is said that Minamoto no Yoritomo the first shogun of the Kamakura shogunate, Matsuo Basho the most famous Japanese poet of the Edo period and Nichiren Shonin the Japanese Buddhist priest and philosopher of the Kamakura period came to this area.
Two of the most important spots in Nasu Onsen are 1,300 year old Shika no Yu, the oldest hot spring in Tochigi and Kita onsen. These spots are called Tojiba which is an onsen where you can stay for extended periods to recover from disease or injury.
According to myths, Shika no Yu was discovered in 630 by Karino Saburoyukihiro the local governor who was chasing a wounded white deer found it bathing in the hotspring. Karino was amazed to find the hotspring healed the deer, and so it was named “Deer’s hot spring.” When he found this place, the thick fog had rolled in and covered everything around there. An elderly man with white hair the god of hot springs suddenly appeared in front of him and said “The white deer being wounded and magically being healed in these waters. The sulphur hot springs are mighty good for people as well.” ​
After that Karino Saburoyukihiro built a shrine dedicated to the elderly man with white hair as the hot spring deity and offered deer antlers as a tribute.
Now the shrine is called Yuzen shrine and he is also enshrined there as a discoverer of Shika no Yu.
The pattern on the drum at the main shrine resembles an inverted swastika and is inspired by deer antlers.

In this historic area, visitors can enjoy 100% natural hot springs without any filtration or additives, as well as open-air baths surrounded by nature. The area is known for “Nasu Twelve Springs” the twelve spots in this area offering six diverse types of hot spring water. Also, it was ranked second (East Ōzeki) in the hot spring rankings of the Edo period.
Nasu Onsen (Hotsprings), with a history of 1,400 years still maintains its historical look. It is one of Japan’s most renowned hot spring destinations.

The terrain in Nasu area tells the story of the geological events of the past 100 million years.

The layers of sediment deposited on the seafloor over 100 million years ago were uplifted by orogenic movements. It became Yamizo mountains that located on the border with Ibaraki, Fukushima and Tochigi. Afterwards, there was a large river flowing from Fukushima toward Utsunomiya in Tochigi and a large lake around Nasunogahara area.
The volcanic activity that happened around 1.6 million years ago in the Aizu region of Fukushima caused several large eruptions and pyroclastic flows. The eruptions continued creating, Mt. Kashi Asahi around 500,000 years ago; Mt. Sanbon-yari 300,000 years ago; Mt. Asahi and Minami-Gassan 200,000 years ago; and Mt. Chausu about 16,000 years ago, finally taking the form we see today. The most recent eruption occurred during the Muromachi period (1408-1410).
About 1.2 million years ago, these flows spread to Tochigi, covered the area with thick pyroclastic deposits over 100 meters (328ft.) deep. This is the well-known stone Ashino ishi. It is also widely and thickly distributed underground in the Nasu Highlands.
Ashino Ishi stone is produced in the Ashino area and is known for its durability and water resistance. It has been used for various purposes since ancient times, including the foundations of shrines and temples, stairs, walls, storehouses, and tombstones. It had gained fame alongside Oya ishi stone in Utsunomiya. It is also used in modern architecture, such as the Stone museum in Ashino designed by Kengo Kuma the famous Japanese architect. If you visit this area, you will surely feel the history of the volcanic activity.

Mother nature mountains the Nasu mountain range is providing abundant blessings to the plants, animals, and people living in Nasu.

The Nasu mountain range occupies one-third of Nikko National Park. Mt. Chausu is particularly symbolic and continues to release smoke. It’s affectionately known as “Nasudake (Mt. Nasu).” The diverse and beautiful mountain and wetland landscapes today were created by the active volcanos. The forest limit lines are low and from the summit a breathtaking panorama view of the Kanto plain can be had.
The volcanic activity not only creates abundant hot springs and rich nature but also impacts the habitat of plants and animals. One such volcanic vegetation are azalea flowers which bloom in spring. The vibrant fall colors gradually reveals colorful tapestries as the leaves change over multiple elevations.
The climate of the Nasu mountain range provides water, which is deeply connected to the local food supply, including rice, vegetables, and dairy products. People in Nasu are living in harmony with nature. They see the mountains everyday and respect the rhythms of nature.

Climbing Mt. Nasu, experience the power of the volcanic activity.

Mt. Nasu (Mt. Chausu) is a volcano that continues to exhibit vigorous activity. You feel the energy of the volcano, described as the breath of the Earth itself.
If you hike, there are several spots that you can find the energy of the volcano. One of them is the abandoned sulfur mine. That was used for sulfur and alum mining since the Edo period. These raw materials were used for gunpowder and supplied by the Kurobane clan to the Edo Shogunate.
It became a tourist spot and mining continued until around the 1950s (Showa 30s). It supported people’s livelihoods in Nasu and brought vibrancy to the Nasu Yumoto hot spring area. Another place is the extremely hot sulfurous gas vents. There’s no vegetation grows due to volcanic gases. A roaring sound reminiscent of a jet engine makes you to feel the power of the volcano.