Hot spring (onsen) facilities have rapidly increased in recent years, and it has become easy for anyone to enjoy hot springs. Kyushu Island in particular is famous for its hot spring resorts.
We would like to introduce some trivia on hot springs here. Read this well to become a hot spring expert!!
We would like to introduce some trivia on hot springs here. Read this well to become a hot spring expert!!
１．What kind of hot water do you call “hot spring”?
In Japan, hot springs are determined by the “Hot Spring Law” (onsen law), which establishes that hot springs are that which discharge hot water from underground at over 25 degrees Celsius (77 degrees Fahrenheit), mineral water, vapor, and/or other gases. A water source is determined to be a hot spring if the water is over 25 degrees Celsius, or if it is under 25 degrees Celsius, meets the defined amount of at least one of the nineteen elements, such as hydrogen ion.
2. What are the advantageous effects of hot springs?
Hot springs are said to have two advantageous effects, which are called “general indications” by bathing and “spring quality-specific indications” for medicinal effect. “General indications” are said to include neuralgia, muscular pain, arthritic pain, stiff shoulders, motor paralysis, stiff joints, bruising, sprains, chronic digestive illnesses, sensitivity to cold, fatigue relief, and health enhancement. “Spring quality-specific indications” signify that potencies exist according to the “spring quality,” which is determined by water composition and quantity. While hot springs can be helpful in building your health, it can also have adverse effects, depending on the condition of your body, so select specific potencies when you bathe in hot springs!
3. What is pH (hydrogen-ion concentration)?
Many hot springs list the pH levels of their water in their descriptions. It is often said that “this water is mildly alkaline, so it appears to be good for the skin.” pH levels indicate the degrees of the acidity and alkalinity of the water, and it is a component that determines the texture of the water. In general, alkaline hot springs have the same effect as soap and feel slippery to the touch. This is why mildly alkaline hot springs are called springs for beauties or beautiful skin. On a side note, pH 7 is neutral, and the lower the pH level, the more acidic the water; the higher the pH level, the more alkaline it is.