An onsen is a natural hot spring bath in Japan. The water in an onsen is geothermally heated beneath the ground and rises to the surface bubbling hot. The prerequisites of an official onsen are that the water must contain at least one of the 19 designated chemical elements that naturally occur in hot spring water, and it must be at least 25C when it comes out of the ground. Onsen water has been believed to have a multitude of healing properties basically since time began, and is rich in beneficial minerals.
An onsen typically has an indoor bath tub, a big open-air bath tub (known as a "rotenburo"), and a place for washing, with complimentary soap and shampoo products for guests to use. Some onsen may also have additional facilities like a cool-water bath or a sauna. Visitors to Japan should not miss the opportunity to visit an onsen and experience the unique and therapeutic properties of its waters.
To enjoy an onsen safely, there are some rules and manners that visitors should follow. These include washing thoroughly before entering the bath, not placing the head underwater, and not bringing glass inside the area. Visitors should also not enter the bath after drinking too much, and should not be drunk inside the bathtub. It is also customary to wipe oneself lightly with a wash-towel before entering the locker room to keep it dry and clean. After wiping the body completely with a bath-towel in the locker room, visitors can wear "yukata," a kind of kimono, to enjoy the onsen comfortably.
