Koutakuji Onsen

Koutakuji Onsen in Atsugi City, Kanagawa Prefecture takes its name from the Koutakuji temple — also written Hirozawaji — located in the Nanasawa district of the Tanzawa foothills, and represents one of the springs within the Nanasawa Onsen cluster of the broader Sagami thermal region accessible from the Tokyo metropolitan area. The spring flows with simple and siliceous thermal waters, combining the gentle mineral warmth of simple-type onsen with the additional silica content that contributes to the smooth, silky skin texture many bathers experience after immersion in siliceous spring water. Koutakuji Onsen is home to the single inn Gyokusuiro, making it an example of Japan's intimate ipponshibori tradition where a solitary establishment serves as the exclusive custodian of a natural spring, offering guests a deeply personal encounter with Kanagawa's geothermal heritage within the forested hills of the Tanzawa range.