First used by injured warriors to heal their wounds, hot springs became important because of the significance of cleanliness in Japanese culture. In medieval times inns were built for samurai, feudal lords and their retinues visiting hot spring locations. For ordinary people, visiting an onsen was like taking a holiday.
As Japan opened to the outside world in the Meiji era and industrialisation started, Onsen began to attract people from the expanding cities and western-style hotels were built. Onsen still attract a large percentage of all domestic tourists in Japan, who travel on short packages to soak in the thermal waters and enjoy the local cuisine.
Onsen differ from hot springs in other countries in several respects. First, the water is usually hot, around 37- 42 degrees Celsius is average. The baths where you soak can normally accommodate ten to twenty people, though many are smaller and many larger. Baths are often built from stone or sometimes wood – Hinoki cypress is a prized material.
The other major difference is that clothing is not allowed and bathers are naked. Until the early part of the 20th century most onsen were mixed, but gradually the number of mixed onsen has declined under pressure from foreign missionaries. Today only a tiny minority of Onsen offer mixed bathing and they tend to be the more remote and secluded ones.
Visiting an onsen is a must on any visit to Japan. There is simply nothing like it and most visitors become addicted! Even if you feel shy about being naked in public, it is well worth trying. Start off by going at an 'off-peak' time; if you are bathing at a Japanese inn, your host will tell you when the bath is likely to have fewer people.
All onsen must by law display their mineral content and temperature; so check before going into the water. Some onsen are not suitable for those with heart conditions or high blood pressure – again, please check.
The name of an Onsen on a map in Japan usually refers to the collection of inns using that particular thermal source, not to an individual inn. So, for example, Nyuto Onsen in northern Japan refers to the spring and its attached group of inns; Tsuru-no-yu is the name of one of those inns. People choose Nyuto Onsen for its famous milky-white water.
The simplest Onsen are rock pools in the mountains where the thermal water is free for anyone to use. Next are local village Onsen, run by the village primarily for residents, but open for visitors too. Usually indoors, they resemble Sento public baths in towns and cities and they provide a meeting place for the community. There is an entry fee of a few hundred Yen and you can stay as long as you like.
Most visitors experience Onsen bathing at one of the Ryokan or Minshuku grouped together around a source of thermal water. Their baths may be for exclusive use of overnight guests, but many inns welcome Higaeri (daytrip) visitors to bathe for a small fee. There may be a whole series of baths, both indoor and outdoor; smaller Kazoku-buro (family baths) can be reserved for a particular period and then used by one party for greater privacy.
The largest ‘Ryokan hotels’ at hot-spring locations are modern buildings with hundreds of rooms, many large baths and an intriguing blend of western and Japanese styles. Though less traditional in feel, they can be great fun and are a good place to see the Japanese at play.
In certain locations, thermal water emerges through riverbeds. At Kawayu Onsen in Wakayama prefecture, people move stones on the shallow riverbed to channel hot-spring water and allow them to soak in the river. Perhaps the hottest hot spring is Nozawa Onsen in Nagano, where the villagers use the water to cook eggs. South of Kagoshima, on the southern island of Kyushu, hot water bubbles up on the black volcanic sand beach. The hot sand is then mixed to the right temperature and bathers lie on the sand and are then covered up to their necks.
If you are not a guest at the inn or are visiting an Onsen not attached to a particular inn, you will need to pay first at reception. Remove your shoes and place them in the lockers provided. Your entry fee may include a small white towel, which is yours to keep.
The bathing area will normally have Noren curtains over the entrance - red for women, blue for men. Inside you will find the changing area, with shelves and baskets for your clothing. Remove your clothes, place them in the basket and keep with you just your small white hand towel. If you have a larger bath towel too, leave it in the basket as it will get wet if taken into the bathing area. It is acceptable for men to carry razors for shaving while into the washing area.