Waitakan, officially known as Yuyado Oguni no Auberge Waitakan, is a secluded hot spring inn located at the foot of Mount Waita in Oguni Town, Aso District, Kumamoto Prefecture. Situated at approximately 700 meters above sea level within the Aso-Kuju National Park, this tranquil retreat is surrounded by magnificent natural scenery. The most distinctive feature is its mystical milky water that changes color daily, ranging from milky white to pale cobalt blue. The spring water is a sodium chloride spring (hypotonic alkaline high-temperature spring) with a source temperature of 96.5 degrees Celsius and a pH of 8.5. It contains an exceptionally high concentration of metasilicic acid at 461.4mg/kg (50-100mg is normally considered sufficient for skin-beautifying effects), earning it a reputation as a bijin-yu (beauty bath). All baths are 100% free-flowing natural hot spring water. The facility offers a diverse range of bathing options including Tenku-no-Yu (rooftop open-air bath), Chikurin-no-Yu (bamboo grove open-air bath), Sasa-no-Yu (semi-open-air bath), Waita-no-Yu (indoor bath), Yubatake-no-Yu (mixed bathing open-air bath with bathing wear), and a reclining bath. The cuisine features French-Italian fusion bistro-style dishes using Kumamoto brand wagyu beef and local game. The inn has 5 Japanese-style rooms including a detached cottage with a private open-air bath. As an adults-only retreat, guests under junior high school age are not permitted to stay.