what is onsen in japan

Onsen is a Japanese word that means "hot spring". It refers to natural hot water baths that are rich in beneficial minerals. Japan has approximately 25,000 hot spring sources, and there are over 2,900 onsen hot spring resorts scattered throughout the country. Onsen water 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 may be either outdoor baths or indoor baths. Traditionally, onsen were located outdoors, although many inns have now built indoor bathing facilities as well. Nowadays, as most households have their own baths, the number of traditional public baths has decreased, but the popularity of sightseeing hot spring towns has increased. Onsen can be enjoyed at ryokan, hotels, and public bathhouses. An overnight stay at an onsen ryokan is a highly recommended experience for any visitor to Japan.