Tamagawa hot spring
Hot Spring Overview
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.
About Secluded Rating
Access (Difficulty to Reach)
15min walk
Scenery & Atmosphere
Untouched nature
Onsen Value
Historic unique spring
Although it takes over an hour by bus from the nearest train stations, public transportation to Tamagawa Onsen is relatively well-established, and access by private car is also possible. However, road conditions in winter require caution.
With its extremely acidic water (pH 1.05), geothermal bedrock bathing, and the presence of hokutolite (a rare radioactive mineral), Tamagawa Onsen offers a truly one-of-a-kind hot spring experience.
Rather than a typical "hidden hot spring," it gives the impression of a hot spring from another world.
That said, due to its popularity and large number of therapeutic visitors, it may lack a sense of seclusion for those seeking a quiet, untouched retreat.
The surrounding environment is equally remarkable, with the rugged mountainous landscape of Hachimantai, rising geothermal steam, and fumaroles creating a dramatic and mystical natural setting.
Historical records trace the origin of the hot spring back to the Nara period, and it was formally developed as a therapeutic bathhouse in 1885. As the birthplace of ganbanyoku (stone sauna therapy) and one of the few places in the world where hokutolite is found, its cultural and medical significance is exceptionally high.
Hot Spring Details
Practical Info
Visit Log
Bath Types
Facilities
Access Information
From Tazawako Station on the Akita Shinkansen / JR Tazawako Line, take the Ugo Kotsu Bus to Tamagawa Onsen (approx. 1 hour 20 minutes).
Alternatively, from Kazuno-Hanawa Station on the JR Hanawa Line, take the Shuhoku Bus, which takes about 1 hour 15 minutes.
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