Osawa Onsen is an inn with a history of 1,200 years, surrounded by the great outdoors along the Toyosawa River, which can be called the cradle of the four seasons.
Sansuikaku is a Japanese-style inn with sophisticated modern architecture and various facilities. There are four types of guest rooms overlooking the mountain stream, including the "Peony Room" which is a reproduction of the room beloved by Kotaro Takamura, and a two-room room with a cypress bath. The room is a space where you can enjoy the colors of the trees, the sounds of the rapids, and the Japanese atmosphere that is unique to Japanese rooms.
This is an inn that wants even people who are unfamiliar with touji to learn about its benefits. Currently, the "Self-Cooking Toujiya" welcomes guests for touji, with three baths waiting for you. The famous mixed-gender open-air bath, "Osawa no Yu," is the subject of an anecdote from when Miyazawa Kenji was a student and played a prank by stopping the waterwheel that pumps the hot spring water. It has been a social gathering place for bathers since ancient times. Its appearance alongside the flow of the Toyosawa River is truly spectacular, with a spectacular view and a sense of openness. The thrill of soaking in the free-flowing hot spring water while thinking about history can only be experienced here.
There are also designated bathing times for women, so you can enjoy the feeling of a hidden hot spring along with the women-only "Kawabe no Yu." Regular customers highly recommend the indoor bath "Yakushi no Yu," which warms you from the inside out. The bath space has been renovated while retaining the tasteful retro tiles of the past, and still exudes the atmosphere of a hot spring resort.

The tour of the baths continues to the Sansuikaku bathhouse, but it is a rule to take breaks in between.
After taking a rest, head to the "Sansui no Yu" bath, which is exclusively available to guests. The large bath, with its impressive high ceiling and large glass windows, is spacious and open, allowing you to stretch your limbs and refresh yourself while gazing at the poetic colors of the mountains. The atmosphere of the adjacent open-air bath is also exceptional. You will also be soothed by the sunlight filtering through the trees, the murmuring of the stream, and the sound of the wind.
The other is Toyosawa-no-Yu, a semi-open-air bath by the river for men and women. During the deep green to autumn foliage season, the glass doors are open, making it a semi-open-air bath, but in the winter, when the snow scenery is beautiful, it is partitioned off and becomes an indoor bath.
Sansuikaku also has three private baths available for guests to use free of charge from 3pm to midnight and from 6am to 10am the following morning.
Guests can enjoy a monthly changing "honkaku kaiseki meal" using the most delicious seasonal ingredients and carefully prepared by hand in the modern dining room or private banquet hall.
One place you should definitely check out is the multi-purpose thatched roof hall "Mukashi Gallery Chigaya" at the Nanbu Clan Thatched Roof Kikusui-kan. The building was created in 2023 after the renovation of a rare thatched roof building. The gallery displays photographs and postcards related to Kenji, as well as items that commemorate the history of Osawa Onsen.
This is the "Village of Hot Springs for 1,200 Years," where the four seasons change. The hot spring therapy culture and history are alive and well, and should be known by modern people.