The exploitation of hot water for religious, relaxation and medical purposes, represents an eradicated tradition in Japan. Favoured by its geology and location, the nation counts thousands of springs and bathing facilities, accessed by multitudes of natives and tourists. Among the available typologies, onsen represent the most interesting establishments. Their fascination, in fact, transcends the attractiveness of relaxation: the process of bathing, imposing a rigorous etiquette, along with architectural choices and the attention to the natural environment, consist in a unique combination. Despite a strong centenary tradition, the onsen sector, after the bursting of the Economic Bubble in the 90s, has undergone a phase of crisis.