Furuyu Onsen Kakureisen, officially known as 'Tsuru no Ongaeshi Yomigaeri no Yado Kakureisen,' is a historic hot spring inn located in Fuji-cho, Saga City, Saga Prefecture. With a history said to span over 2,000 years, legend has it that the spring was originally discovered during the reign of Emperor Korei but was buried by a flood and forgotten. Years later, local people noticed cranes healing their wounds in a nearby pond, dug into it, and rediscovered the ancient hot spring. The renowned poet Mokichi Saito also stayed here. The inn's most distinctive feature is its nationally rare natural sand bath, designated as a Hot Spring Heritage site, where hot spring water bubbles up through sand spread across the bottom of the bathing pool from the bedrock below. The water is an alkaline simple hot spring with a pH of 9.5, at a lukewarm temperature of around 38 degrees Celsius, ideal for long soaking sessions. Known as a 'beauty bath' for its silky smooth texture, the inn offers two pools: the sand bath at natural temperature and a heated pool. Alternating between the two is said to stimulate metabolism. This intimate ryokan with only 9 rooms provides a tranquil mountain retreat for therapeutic bathing.