Shinmeikan is a venerable inn founded in 1908 (Meiji 41), located along the Tanohara River at the heart of Kurokawa Onsen village in Manganji, Minami-Oguni, Aso, Kumamoto Prefecture. Standing as a witness to the dawn of Kurokawa Onsen itself, the inn is famed above all for its hand-carved cave bath, Ana-yu — a 30-meter-long tunnel chiseled out of solid rock by the third-generation proprietor Tetsuya Goto. Beginning at the age of 24, he labored for roughly three and a half years (some accounts say up to ten years) wielding only a chisel and mallet to excavate this remarkable bathhouse by hand. Inside the steam-filled cave, the path branches and reveals two stone tubs glowing in mystical half-light, offering an utterly unique bathing experience found nowhere else. Adjacent to the inn flows the Iwato-buro, said to be the very first open-air bath in Kurokawa Onsen, carved out of the natural riverside rock and blending seamlessly with the azalea-clad hillside. The source, named Koba-no-se Onsen, emerges at 80.3 degrees Celsius with a pH of 6.8 — a hypotonic, neutral, high-temperature spring of the sodium chloride and sulfate type. The water is delivered as pure free-flowing onsen with absolutely no dilution, no heating, no circulation, and no chlorination, and is known to benefit cuts, peripheral circulation disorders, chronic cold sensitivity, mild depression, and dry skin conditions. Nurtured by the late Tetsuya Goto, who devised the famed Nyuto Tegata bath pass in 1986 and is widely credited as the architect of Kurokawa Onsen''s revival before passing away at age 86 in January 2018, Shinmeikan continues to command deep affection from onsen lovers and Kurokawa devotees alike.