Keiunkan is an inn that has stood the test of time. It is registered in the Guinness World Records as "the world's oldest hot spring inn." It was founded in 705 AD, during the fifth Keiun era, counting from the Taika era. The inn's name is also derived from the era. Perhaps it would be more accurate to say that it was founded five years before the capital was moved to Heijo-kyo and 15 years before the Kojiki was compiled. The current owner is the 53rd generation. To get to Keiunkan, you have to go all the way up the Southern Alps Highway along the Hayakawa River from the Minobu area. After passing through a steep valley and several tunnels, a modern Japanese-style building suddenly appears in the deep forest. When you arrive, everyone says, "We've finally made it!" Even though it's a long way away, inside the inn, there is a wonderful hot spring that will make you forget your fatigue. Your heart will be filled with anticipation.
Running through Hayakawa-cho is the Fossa Magna, which divides the Japanese archipelago into east and west. The difference in the fault line can be seen from inside the inn. The four springs, which have been nurtured over the years underground in this great rift valley and spring up naturally without ever drying up, have nurtured the history of the inn. This famous hot spring has been loved as a "hidden hot spring in the Kai mountains" by people of the capital such as Fujiwara no Masato (Kamatari's eldest son), whose name is remembered in the history of the hot springs, as well as famous generals of the time such as Shingen and Ieyasu, and literary figures.

As part of a commemorative project marking the 1,300th anniversary of the inn's founding, the hot spring was excavated and discovered a natural spring with a temperature of 52 degrees and a flow rate of over 1,600 liters per minute (about 8 drums), the largest in Japan. When combined with the existing spring source, this amounts to about 2,000 liters per minute. At Keiunkan, the water flows freely without adding water or heating, not only for the six types of baths, but also for the guest room baths, hot water, and showers. The water is colorless and transparent, highly alkaline, and has excellent skin-beautifying properties. Drinking the spring water is also effective against digestive disorders and diabetes.

On the fourth floor is the open-air bath "Bokei-no-yu", which is the face of Keiunkan. The bathtub is made of Japanese cypress, which has a unique fragrance and a pleasant texture, and the hot water overflows, while the murmuring of the Hayakawa River and the breeze blowing across the river are soothing. On the top floor are the observation baths "Hinoka-no-yu" and the stone bath "Sekifu-no-yu". As the building is located on the mountainside, you can see the panoramic view of nature as if it were right in front of you. The bathtub in Hinoka-no-yu is made of ancient cypress that has taken root for over 2,000 years. The hot spring water blends with the ancient cypress's warmth, making it very comfortable. If you want to enjoy the atmosphere of a deep mountain valley while soaking in a hot spring by the river, try the stone bath "Keiryu Open-air Bath Hakuho-no-yu" or the private open-air stone baths "Kawaoto" and "Seoto", which can accommodate groups of 15 people. The bathtub in Hakuho-no-yu is made of Hakuho stone mined in the Hayakawa River basin, and turns a deep blue when hot water is poured over it. This is also a product of the Fossa Magna.

All of the guest rooms feature an open-air bath and an indoor bath that flows directly from the source, and are purely Japanese in style. The rooms are designed with great care to respect Japanese traditions. The special guest room "Kitadake" with an open-air bath that flows directly from the source is a luxuriously spacious space consisting of a gorgeous 16-tatami room, a stylish 8-tatami room, and an antechamber. The fragrant open-air bath made entirely of cypress will also take you to a state of ecstasy. After your bath, head to the wooden deck moon-viewing terrace. You can enjoy a blissful time watching the valley and the nature on the opposite bank from the best angle.

The cuisine is the Miyama Kaiseki, handmade by the head chef, who won the Minister of Land, Infrastructure, Transport and Tourism Award in the local cuisine category of the National Japanese Cuisine Competition, and is a combination of the best of Japanese cuisine. No seafood is used, and the dishes, which are made using the seasonal bounty of the mountains and rivers, can only be enjoyed at Keiunkan. Everything from fish paste to mayonnaise is made by hand, and eight different types of salt are used depending on the dish. The Koshu beef, which is purchased in its entirety, is the highest grade A5, and has won gold awards in consecutive years. The lava-grilled Koshu beef, which is grilled on lava from the second station of Mt. Fuji, is a true masterpiece. No matter when you visit, you can experience this deliciousness.
The natural world repeating the cycle of the four seasons and the hot springs bubbling away endlessly... It is lovely that nothing has changed in the last 1,300 years. My sense of travel will take me back in history.