Shichimi Onsen

Shichimi Onsen in Nagano Prefecture takes its name from the concept of seven flavors, an allusion to the remarkably complex mineral profile of waters that combine bicarbonate, sulfate, and mildly radioactive characteristics in a single geothermal source found in the volcanic mountains of former Shinano Province. The mildly radioactive quality — associated with dissolved radon gas — is considered in traditional Japanese and European balneology to have tonic and immune-stimulating effects, a practice that has been part of therapeutic spa culture on both continents since the early twentieth century. Shichimi Onsen's extraordinary mineral diversity within Nagano's already celebrated onsen landscape makes it a destination of particular fascination for visitors who approach thermal bathing as both a pleasure and a scientific inquiry into the earth's geochemical gifts.