Sanbe Onsen is a historic hot spring area spread across the southern foothills of Mount Sanbe in Shigaku, Sanbe Town, Oda City, Shimane Prefecture. The hot spring is said to have been discovered during the Hakuho period (late 7th century), and was long known as Shigaku Onsen. During the Edo period, miners from the nearby Iwami Ginzan Silver Mine are said to have visited to soothe their fatigue. In the Meiji era, an army training ground was established in the area, and at its peak, some 3,000 soldiers were stationed nearby and used the baths. In 1959, the hot spring was designated a National Health Resort by the Ministry of Health and Welfare, and was renamed Sanbe Onsen.

The spring quality is an iron (II, III)-containing sodium chloride spring (hypotonic, mildly acidic, low-temperature spring) with a source temperature of approximately 37.6 degrees Celsius. Due to its high iron content, the water is transparent when it first emerges but oxidizes upon contact with air, turning a distinctive tea-brown color. The total flow rate of all Sanbe Onsen sources reaches approximately 3,000 liters per minute, the largest in the Chugoku region. At Tsuru-no-Yu, source water gushes powerfully through thick pipes over 5 centimeters in diameter, constantly overflowing from the bath. The water is heated to approximately 39-40 degrees Celsius.

Shigaku Yakushi Tsuru-no-Yu is a traditional public bathhouse located in the Sanbe Onsen town, long beloved by local residents and visitors seeking therapeutic bathing. During its heyday in the mid-Showa era, approximately 30 inns and health facilities lined the surrounding area. The current building was reconstructed during the Heisei era and maintains a simple sento-style design with no showers or amenities. Hand baths and foot baths are available outside. An Ichibata Yakushi temple hall stands adjacent to the bathhouse, and a festival is held every late July. Admission is 400 yen for adults and 200 yen for elementary school students. Operating hours are 12:00-21:00 (until 20:00 from November to mid-April).