About Hot Spring

Here MyJapanPhone will introduce some information about hot spring, hope it can help you during your Japan travel. Hot springs are not only water lines that are based on rain water being heated by earth's magma. Many of the hot springs are virgin water springs (in some of areas when the earth's core is cooled down and it releases gases and water vapor which turns into hot water) or fossil liquid (when ancient live forms died at the beginning of time the remains dissolved and turned into oil or water). The "Hot spring bill" signed in Syouwa 23rd year states: 1) Water temperature needs to be higher than 25c. 2) The water must contain a pre-required amount of minerals in 1kg of hot spring water. So if the water meets both criteria’s then that water can be claimed as a hot spring.
There are many different kinds of hot springs for different uses and different features:
Simple Springs
Water temperature is higher than 25c. Have less than 1gram of radical carbon, salt and other mineral elements. Good for neuralgia and rheumatism, also it is mild making it perfect for long term rehabilitations.

Carbonate Springs
Has less than 1gram of radical carbon and other mineral elements in each liter. Basically close to the Simple Spring water but as you can guess from the name it is carbonated. Many of them are low temperature and cold water springs. Good for heart disease, blood circulation disorders, neurological disorders, female disorders.

Heavy Carbon Soil Springs
More than 1gram/litter of radical carbon and other mineral elements. Good for rheumatism, neuralgia, chronic skin disorder. Also good for drinking to treat digestive problems and inflammation of the bladder.

Salt Springs
Next to Simple springs in numbers, has more than 1gram/liter of mineral elements. If the water contains more than 1gram but less than 5gram of salt it is a weak saltine spring if less than 10gram then it is a Salt Spring , if more than 10gram the it is a Strong Salt Spring. Since is highly sufficient in keeping temperature it is called "Atsu no yu" (Warm hot water)

Saltine Sodium Hydrogen Carbonate Spring
Salt springs with Sodium hydrogen carbonate content, alkine base.

Mirabilite Springs
Good for arteriosclesis or cholecystitis and rheumatism. Sulfite natrium base bitter spring. Not recommended for drinking.B

Mirabilite Sodium Chloride Springs
Mirabilite springs with sodium chloride content. Good for same usage as Salt Springs and Mirabilite springs.

Gypsum Springs
Good for rheumatism or wounds also help the metabolism when drank. High in calcium content bitter spring.

True Bitter Springs
Sulfite magnesium is the main mineral content, good for rheumatism. Low in numbers.

Iron Springs
Two different kinds of springs: Carbonate iron springs and green vitriol springs. When the water is boiled it turns red. The green vitriol springs contains sulfite iron and strongly acidic vitriol.

Acidic springs
Indigenous to Japan. Mainly in volcanically active area, high concentration of hydrogen ions. Hard to bath in and should be advised before taking a bath.

Alum Springs
Main mineral element is sulfite alum. Good for skin disorders. Mostly acidic alum or acidic alum green vitriol springs.

Sulfer Springs
Contains Sulfhydryl ions or Sulfer hydrogen, smells like rotting eggs. Good for drinking and treating many disorders.

Radium Hot springs
Contains a certain amount of radium or throne, good for digestive disorders or rheumatism.
The hot springs not only contain minerals but the water pressure and buoyancy is also good for stimulating the body. Just the hot springs are good for you, doesn't means you should stay in the spring for a long time. Try to keep it around 2, 3 times a day 30min each including washing time. (10min physically in the water, water temperature above 104F) If the water temperature is below 104F then it is better to take long bathes. Luke warm low mineral content water it is better to stay longer. If the temperature is high then don't go straight into it, but warm yourself up before you go in. It always is nice to do so anyway for others in the bath so that they know you cleaned yourself.