Some additional information:
There are about 1,100 hot springs of recognized medicinal value in this country. Some are situated in remote parts of the country where old customs and manners are still retained, whole others are in tourist resort areas, and are provided with all the comforts usually associated with the amenities of travel.
A hot spring is traditionally considered in Japan to be the best and most efficacious resort curing protracted illness. There is a saying to the effect that a disease will prove fatal that is not healed by taking the baths at a hot spring, sometimes five or six times a day, for three cyclic periods of seven days in three consecutive years. The orthodox Japanese, particularly in the rural districts, seen to rely more upon the efficacy of a mineral spring than upon the effect of modern medicine for the cure of a disease, though as a general practice one does not stay at a hot spring more than three weeks at a time, or, as they say, three cyclic periods of seven days.
The spring are classified as simple cold, thermal, and carbon-dioxated sorings, earthy carbon-dioxated and alkaline springs, common salts, bitter, iron carbonated, vitriol, and sulphur springs.
Temperatures of hot springs range from 14 to 102 Centi-degree.
In Hokkaido, the most popular spa is Noboribetsu. It is situated in a region of magnificent scenery, amid boiling mud pools and sulphur fume jets.
One of the inns in the spa has bathroom, largest of its kind in the the country.
Jigokudani (Valley of Hell) at Noboribetsu Spa is supporsed to be a crater formed by a volcanic upheaval in ancient days. The bottom of the crater, which covers an area of some 1- hecrares, is corrugated with entangled masses of yellowish white sulphurized rocks and from under the ground there gushes out a great deal of hotspring water and vapor.
If you have an occasion to take a traditional Japanese-style bath (and hopefully you will have because it is one of the most civilized customes ever developed) you will want to know a few of the rules.
The bather does not wash inside the tub. He douses himself with hot or warm water, either from the tub or a spigot provided for that purpose, soaps up, scrubs carefully, rinses himself and then gets into the tub to soak.
If the bath is the communal type, whether segregated by sex or co-education, it is polite etiquette to cover one's self with a tenugui (small hand towel). It is also customary not to stare when bathing in mixed company. One warning: a person should not enter a hot bath after drinking heavily. The combination of alcohol and hear can be dangerous.