linguistic:paraphrasing
Public baths

In public baths, there is a distinction between public baths with natural hot springs (called onsen, meaning 'hot'), and those without natural hot springs (known as sento). Since Japan is located in a volcanically active region, there are many hot springs, of which about 2,000 are swimming pools. Most onsen are in the open countryside, but they are also found in cities. In Tokyo, for example, there are about 25 onsen baths. Onsen are similar to Western-style spas in their therapeutic use of natural hot springs.

An onsen consists mostly of outdoor pools (rotenburo), which are sometimes at different temperatures. Extremely hot springs, where even experienced or frequent hot-spring bathers can only stay a few minutes, are called jigoku ('hell'). Many onsen also have saunas, spa treatments and therapy centers. The same rules apply in public baths as in private baths, with bathers required to wash and clean themselves before entering the water. In general, the Japanese bathe naked in bathhouses; bathing suits are not permissible.