Odaito Onsen Seaside Hotel

The hotel has one indoor bath and one outdoor bath, each separate for men and women, and no sauna. The spring water runs dark and salty, with a strong mineral smell that reviewers say fills the bathhouse. The outdoor bath is kept on the cool side, good for a long soak while looking out over Notsuke Bay toward the Notsuke Peninsula. It's a plain, no-frills hotel on the bay in Betsukai, on Japan's eastern Hokkaido coast, close to the peninsula's ghostly dead-tree forests and wildflower fields, the traditional sailboats that work the bay in summer, and the "square sun" mirage that appears over the frozen bay in winter.