Obuke(The Great Gusher)

Tamagawa Onsen's source, **"Oobuki,"** boasts the largest water flow rate and the highest acidity (pH 1.2) in Japan. More than 9,000 liters of 98°C hot water erupts every minute, creating a spectacular sight. The highly acidic water quality and the radium contained in the Hokutolite are expected to have therapeutic effects, attracting visitors seeking therapeutic bathing and recuperation. Features of "Oobuki" Largest water flow rate in Japan: More than 9,000 liters of hot water gush out from a single source every minute, boasting the largest water flow rate in Japan. Highest acidity in Japan: With a pH of around 1.2, it is an exceptionally highly acidic water quality in Japan, so much so that a nail will dissolve if dipped in it. High-temperature geyser: The temperature of the erupting water reaches 98°C, creating a visually impressive spectacle. Active Volcanic Activity: From the Tamagawa Onsen Nature Research Trail near the source, you can see the large geyser and the active eruption of steam. Benefits and Enjoyment of Tamagawa Onsen: Therapeutic Bathing: Known as a "healing bath" due to its highly acidic water quality and the presence of trace amounts of radium, it attracts many visitors seeking therapeutic bathing. Natural Stone Bath: You can also experience a free natural stone bath using bedrock heated by geothermal energy around the source. Nearby Facilities: Because the water quality is highly acidic, if you experience skin irritation, it is recommended to start with water diluted to 50% and gradually acclimate yourself. Precautions: Effects on Metals: Highly acidic steam floats in the air, which may cause discoloration of precious metal accessories. Effects on Machinery: It may cause malfunctions in precision machinery, so care should be taken when handling it.

(Visited October 19, 2023) This is the source of Tamagawa Onsen, and it's said to have the largest single-source hot spring discharge in Japan. Regardless of the actual figures, seeing it gushing forth is quite impressive, and you can really feel the power of nature. I grew tired of seeing it when I stayed here for long summer vacations as a child, but perhaps because it's been a while since my last visit, I never got tired of the constant gushing of hot spring water. For me, it was a place where I could feel the energy of the earth on my skin and forget about my daily work, even if just for a moment.

If you pass Oofun, you'll find a hut where you can enjoy a natural bedrock bath. I tried the bedrock bath at this hut. I brought a mat with me, laid a bath towel on top of it, and rolled around. Since it's natural, the temperature varies depending on the spot, but it's fun to find the perfect temperature. If you stay at nearby Tamagawa Onsen, you can go back multiple times. However, there are only three huts, so they may get crowded on holidays or at certain times and you may not be able to get in. By the way, the huts are opened and closed by security staff from 6am until 5pm.

Ganbanyoku (Ganbanyoku) I brought a mat, covered myself with a towel, and lay down for about 30 to 40 minutes. It was so hot I started to sweat, and if I had the time, I would have liked to stay there longer. Bath Each person's washing area is separated. Shampoo and body soap are provided. It's best to start with 50% of the water and then move on to 100%. There was also a hair dryer in the changing room. This is the best hot spring. I've heard it's the best in the world.

Tamagawa Onsen has very strong acidic water, even by Japanese standards. There are 100% and 50% spring waters, and the 100% spring water is quite stinging. What was great about this hot spring was that you could get very close to the steam. I recommend seeing the big gust of hot spring water before entering the hot spring. 😄