Tamagawa hot spring

Tamagawa Onsen is a renowned hot spring located in Towada-Hachimantai National Park in Senboku City, Akita Prefecture. It is famous nationwide for its extremely acidic hot spring water that gushes out at a rate of 9,000 liters per minute from a spring source called "Ohbuki," the largest single-source output in Japan. The discovery of this hot spring dates back to 1680 when local matagi (traditional hunters) found deer healing their wounds in the hot water. Originally called "Shika-no-yu" (Deer Hot Spring), it has been operating as a therapeutic hot spring resort since 1885, with over 140 years of history.

The distinctive feature of Tamagawa Onsen is its extremely acidic water with a pH of 1.05, the most acidic in Japan. This rare hot spring water has hydrochloric acid as its main component and contains radium. The low-dose radiation hormesis effect, which has gained attention in the medical field, is expected to promote natural healing abilities. The source temperature reaches 98°C, and the hot spring water flows as a 3-meter-wide stream, creating an impressive spectacle. The area features a high-temperature geothermal zone, and it's famous for hokutolite (a nationally designated natural monument), which exists only here and at Beitou Hot Spring in Taiwan.

Currently, there are three accommodation facilities: Tamagawa Onsen (main facility), Shin-Tamagawa Onsen, and Buna-no-mori Tamagawa Onsen, all drawing from the same source. The natural bedrock bathing area is considered the birthplace of bedrock bathing, where many visitors can be seen lying on mats for therapy. As a authentic therapeutic hot spring resort, it attracts visitors from across the country for long-term stays, making it one of the premier hot springs in the Tohoku region.