|A long soak in a sento, or any kind of onsen, provides more than just hot water to soak the aches from your muscles. The waters that bubble to the surface bring all kinds of minerals that are effective treatments for different ailments. Bathers can pick and choose from springs infused with sodium hydrogen bicarbonate (an alkaline substance that makes skin smooth and supple), calcium sulfate (a sedative ingredient that eases the pain of sprains, bruises, cuts, and burns), and aluminum sulfate (an effective treatment for a number of skin conditions). |
The baths in the Tokyo region are known to contain a number of substances that have percolated up from ancient seawater trapped in the water table. Tokyo onsen are rich in "fossil water," which contains silicate and boric substances that turn the water brown. The areas nearest Tokyo Bay - Ota, Shinagawa, Minato, and Setagaya Wards - are home to a number of sento where you can soak in this kuroyu, or "black water."
But mind that you don't just walk in and jump right into the tub. There are certain rules that must be followed in any onsen. Everyone shares the main tub, so keeping it clean is important. Before getting into the water, bathers scoop some of it out and rinse off their bodies. Washing, too, is done away from the main pool. Soap and shampoo are kept some distance from the tub, and after using them it's important to wash them off of your body entirely before heading back to the tub to soak. It's also important to sit down
when washing to avoid splashing people near you with the spray from your shower.
If you decide to take a trip to an onsen, there
are a few terms to keep in mind. Finding baths like these can make your bathing experience more memorable.Roten-buro: This is an open-air bath. Soaking in hot water is always relaxing, but it can be extra-special when you do it while gazing at the forested hills and sky and listening to the birds of Japan.
Kashi-kiri-buro: This "reserved bath" is one you get all to yourself. Some onsen hotels offer rooms with their own tubs for private use; other establishments let you rent out a bath for 30 minutes or an hour at a time. These are especially popular with families and parents with young children.
Hinoki-buro: These tubs are made from the wood of
the hinoki, or Japanese cypress. The aromatic wood
adds its scent to the water, making for a most relaxing bathing experience.
Yakuso-buro: These baths contain a bag filled with
medicinal herbs or other ingredients. Steeping these leaves and roots adds their essence to the water, making the bath effective for treating any number of ailments.