Kunugi-yu is a family bath facility located in the Hagenoyu area of Waita Onsen Village in Oguni Town, Aso District, Kumamoto Prefecture. All 16 bathing cottages are exclusively private, offering a unique and intimate hot spring experience. Situated at the foot of Mount Waita at approximately 700 meters above sea level, the facility provides stunning views of nature throughout the seasons and beautiful starry skies at night. The spring water is a simple hot spring (hypotonic neutral high-temperature spring) with a source temperature of 44.2 degrees Celsius. The colorless, transparent, and soft water is gentle on the skin and known for its relaxing properties. The most distinctive feature is the coin-timer system that completely replaces the bath water for each use, ensuring that every visitor enjoys fresh, 100% natural free-flowing hot spring water without any dilution or reheating. The facility offers 5 indoor bath cottages (cypress and granite types) and 11 outdoor bath cottages (cypress, rock, special rooms, and observation rooms) with 6 different bath types. Operating 24 hours, visitors can bathe at any time. Bathers can use the complimentary jigoku-mushi (hell steaming) kettles to cook eggs, sweet potatoes, and other foods using natural geothermal steam. Two accommodation cottages with private baths are also available for overnight stays (room only, no meals). The spacious parking lot accommodates 70 vehicles.