道後温泉 第1分湯場
Dogo Onsen No. 1 Distribution StationSodium Bicarbonate-Chloride-Fluoride spring
- Sodium Na⁺
- salt's cation — pairs with chloride to make the water salty.
- Bicarbonate HCO₃⁻
- "soda" — softens skin, leaves it smooth.
- Aches & jointsstiff shoulders
- Smooth skindry, rough skin
- Recoveryfatigue, stress
Water drawn from Dogo Onsen's No. 1 distribution station — an alkaline simple thermal spring at pH 9.0, classified hypotonic, alkaline and hot. Lightly mineralized at just 0.27 g/kg, it is gentle on the body, and the alkalinity gives it a slippery feel that, together with 52.3 mg/kg of metasilicic acid, places it squarely in Japan's beauty-water family. The posted certificate lists the conditions typical of a simple thermal spring — autonomic nervous system instability, insomnia and depressed mood — among its documented indications. The bath is reheated to a comfortable bathing temperature and, to protect the source and keep it hygienic, is run through recirculating filtration with chlorine-based disinfection.
Analyzed Dec 6, 2023·愛媛県立衛生環境研究所