Takayu Onsen Kagetsu Highland Hotel

The hotel's baths run on spring water alone, no added water, no heating, no recirculation, no chlorine: full kakenagashi (かけ流し). The water is a milky, sulfur-heavy onsen that throws off flecks of yunohana (湯の花), mineral flakes that form when the fresh spring meets the air. The indoor bath, Yama-no-yu (山の湯), sits high on the hillside with a wide view of the mountains and no steps to navigate. The open-air Mori-no-yu (杜の湯), set above the tree line, looks straight out at the Azuma range. Two private baths, Himesayuri (ひめさゆり), can be booked by the hour for a quieter soak. Takayu Onsen sits about 800 meters up the Azuma mountainside, a hot spring village with a history running past four hundred years and a remote, out-of-the-way feel. In 2010 the whole village pledged to keep its baths fully source-fed, and this hotel is part of that pledge. Some upper-floor rooms look out over Fukushima city's lights at night.