Japanese Onsen & Sauna Guide
Spring Quality & Science
Deep dive into onsen spring types, components, and scientific knowledge
Japanese Onsen & Sauna Guide
Spring Quality & Science
Deep dive into onsen spring types, components, and scientific knowledge
AllBasic Knowledge and IntroductionThe Appeal of Japan's Hot Springs and SaunasHealth & BenefitsSpring Quality & ScienceThematic GuidesTips for a Successful Trip
26 articles in total
Spring Quality & ScienceSpring Quality Details
Moor Hot Springs: The Story of Brown "Plant-Based" Baths
What are moor hot springs? This guide explains them as springs rich in plant-derived organic matter, such as humic substances and humic acid. Learn why "moor spring" is only a common name, not an official classification, what causes the tea-like brown color and smooth feel, how it differs from iron-colored springs, and why Tokachigawa Onsen in Hokkaido is the best-known example.
Jun 28, 2026
Spring Quality & ScienceHot Spring Science
