Amakazari-so is a secluded mountain lodge located at an elevation of 900 meters on the Amakazari Plateau in Otari Village, Kitaazumi District, Nagano Prefecture. It serves as the Nagano Prefecture-side trailhead for Mt. Amakazari (1,963m), one of Japan's 100 Famous Mountains. The inn is nestled at the foot of Mt. Amakazari, on the border between Niigata and Nagano Prefectures, surrounded by pristine natural beauty.

The hot spring features an abundant natural flow of 240 liters per minute of pure, continuously flowing source water. The spring quality is sodium bicarbonate, a neutral, low-tension, high-temperature spring with a pH of 7.0 and source temperature of 51.8°C. The water is gentle on the skin and provides deep, penetrating warmth. The bathing facilities include separate indoor and outdoor baths for men and women. The outdoor baths offer views of Mt. Amakazari and the Northern Alps, and at night, guests can enjoy stargazing under the clear mountain sky.

Accommodation options include Japanese-style rooms with views of the Northern Alps, Japanese-style rooms with forest views, and Western-style twin rooms. Dining features authentic kaiseki-style Japanese cuisine, including tempura made with seasonal mountain vegetables, fresh Iwana (char) sashimi, teppanyaki with A5-grade Shinshu Premium beef, and hand-made soba noodles, all highlighting local mountain ingredients.

During the climbing season, many hikers use the lodge for pre- or post-climb stays, and the autumn foliage season (late September to early October) is particularly renowned for spectacular views. At 900 meters elevation, the location remains cool and comfortable even in summer. The lodge operates seasonally from mid-April to late November, closing in winter due to heavy snowfall. It's a popular mountain resort destination where guests can enjoy both hiking and hot springs.