A one-inn hot spring ryokan located at approximately 1,540m elevation on the middle slopes of Abo Pass in Azumi, Matsumoto City, Nagano Prefecture, within Chubu Sangaku National Park. Member inn of the Japan Secret Hot Springs Association, established in 1915 (Taisho 4) with a long history.\n\nRelocated to current location in 1998 due to steam explosion from Abo Tunnel construction. Former facility was near the intersection of National Route 158 and the prefectural road to Kamikochi. The old outdoor bath before relocation was on the opposite bank of the Azusa River, a famous roadside outdoor bath visible to cars waiting at Kama Tunnel traffic signal (until June 2005).\n\nFrom current location, can view Hotaka mountain range in the distance. Located about 9km from Kamikochi along old Abo Pass road, used as a base for Kamikochi tourism and climbing Mt. Yake via Nakanoyu route.\n\nThe only year-round operating hot spring ryokan in the Kamikochi area. During winter (mid-November to late April) when Kamikochi is closed, Nakanoyu Onsen continues operating, serving as a base for winter Kamikochi access. Free shuttle service to Kama Tunnel in winter (by reservation).\n\nSpring quality is simple sulfur hot spring, flowing directly from source. Benefits include fatigue recovery, sensitivity to cold, lower back pain, diabetes, neuralgia, general health improvement. In a quiet environment surrounded by primeval forests.