Explains all about Onsen from the science aspects.
Culture of Onsen.
It explains the history and culture of Onsen in Japan.
Welcome to Gero Onsen
Shows the history of Gero Onsen.
Dr. Onsen
... is the library with all kinds of Onsen related books and text.
Onsen Challenge
are experiencing Onsen materials from both cultural and science aspects.
Also, there is great foot Onsen.