Mikagura Onsen

A hamlet on the Tadami River in Oku-Aizu with one bathhouse and one minshuku, sharing a 38 °C spring so charged with dissolved carbon dioxide that it ranks among the most carbonated in Japan — tea-brown, faintly salty, lukewarm enough to sit in for an hour, and drunk as well as bathed in. A second spring rises cold a few minutes away: a well of natural sparkling water that Meiji-era traders shipped to Europe and that is still bottled today.

Aizu-Wakamatsu's traditional onsen quarter, founded in the 8th century. Ryokan packed along the Yukawa river gorge below Tsurugajo castle.