Japanese have no qualms about public nudity. The onsen - hot spring bathhouse - is where people of all social ranks get together, get their kit off and boil themselves like lobsters. The water generally has a high mineral content which affords it healing properties. Onsen etiquette dictates that you give yourself a good scrub with soap and water before submerging yourself in the steaming communal pools. Onsen come in all shapes and sizes: some are indoors and attached to ryokan (traditional guesthouses) or located down narrow inner-city side streets, while others are spacious outdoor affairs on remote mountainsides with multiple pools and adjoining restaurants. Most are single-sexed, although mixed-sexed bathing is optional in some onsen in remote rural areas.