Asahidake Onsen Yumoto Yukomansou

Yukomansou (湧駒荘) is the oldest ryokan in Asahidake Onsen (旭岳温泉), built on springs discovered in 1914 and still flowing untreated straight into the tubs, no added water or heat except for a touch of warming to the annex's outdoor bath in the depths of winter. Bathing is spread across three halls. Yukoman-no-yu (ユコマンの湯) is the original bath, set into rough natural rock, with a low reclining pool and a soak so close to skin temperature that regulars stay in a long time before the warmth spreads through the body. Shikoro-no-yu (シコロの湯) is lined in shikoro wood, long valued for its antibacterial qualities, with two adjoining tubs of different color and temperature to move between. The annex, Kamigami-no-yu (神々の湯), the only bath open to day-trippers, has a high wood-beamed ceiling and a floor paved with flagstone said to date from an eruption of Mt. Asahidake (旭岳) some 500 years ago, plus an outdoor bath that stays open through winter. The ryokan sits within Daisetsuzan National Park (大雪山国立公園) above 1,000 meters, surrounded by forest, and the men's and women's sides of the two main-building baths swap nightly.