In anticipation of the 2020 Summer Olympics, Japan is in the midst of a mini hotel boom. The rooms at the new Amanemu (above), within Ise-Shima National Park, seven hours south of Tokyo by car, are designed to promote total tranquility — all clean lines and warm, woodsy neutrals, with a basalt stone onsen-style tub in every suite. And the high-rise Hoshinoya (below), in Tokyo, will aim to maintain that same hushed, intimate feeling when it opens in July, with an entire floor devoted to onsen tubs, each in a private room with a sliding roof to reveal the sky.