When I read about Tamagawa Onsen online, it said that it is not usually a tourist destination, but more a destination for people with illnesses they wish to be cured. The water has special properties and is home to rocks said to help cure a variety of things. We decided to go check it out!

After we parked in their large parking lot, Hunter and I walked down to a fork in the path. The way left went into the volcanic rock area while the left went to lodging and the onsen. We decided to explore a bit before hitting the baths.

The first thing we saw on the left path was a big sign warning people in both English and Japanese. It said that nearby Mt. Yakeyama is an active volcano, and while it is possible to climb the short distance to the top, hikers should avoid low lying areas in the event of still weather. Without wind to clear the heavy, poisonous gasses issuing from various holes, it collects in dips and valleys and can cause sickness and death.

Continuing on, we were pleased and surprised to find small signs in English and Japanese explaining various things along the path. One of the first ones was about sulfur flowers, deposits of sulfur and other minerals that are left behind when the water evaporates.

Here, the water is being pumped through troughs so that the sulfur flowers can be harvested and used for various things. I saw similar things at Kusatsu Onsen! 

The next one was about the special rocks called Hokutolite ( 北投石)! Come to find out, they are radioactive, and Tamagawa Onsen is the only place in Japan they exist. Cool, huh? People believe that touching them can help treat cancer, so the area is very popular with cancer patients.

And here’s where things got a little odd. As we walked, we noticed a couple of aluminum blankets near the radioactive rocks. As we got closer, we realized that they were people! People dressed in layers, laying on the ground, covered with an aluminum blanket and a small sun umbrella propped up near their faces to shield them from the sun. No lie, it looked like there were baked potatoes dotting the landscape. No pictures of this interesting phenomenon because taking pictures of people without their permission is not something I like to do, but trust me, it was a sight. I don’t know how they didn’t pass out from heat stroke or something!

Here’s something cool — the source of the hot spring. In Japanese it is called 大噴 (obuke), which means “great gusher.” And for good reason too — it produces about 8,400 liters per minute of hot (98C / 208F), acidic (pH 1.2) water. All the steam and gasses that were escaping along with the water were definitely not what I’d call pleasant; the wind changed while we were walking to it, and Hunter and I suddenly found ourselves inside a cloud of the stuff. It changed again soon after, but not before making me move to cover my nose and mouth. It had suddenly become difficult to breathe! I remembered the sign at the beginning of the path, warning hikers about the dangers of inhaling too much gas.

Other than that one instance of difficulty breathing, Hunter and I thoroughly enjoyed walking around the area. The nearby hills are dotted with fumaroles (volcanic vents), and all we could hear was the bubbling of water and the hiss of escaping gasses.

There were signs EVERYwhere warning people not to wander off the paths. Besides the obvious dangers of boiling water and poisonous gas, some of which is spewing out at over 100C, much of the ground is unstable and could give way underneath you.

Once we were done exploring, it was time to hit the baths! Obviously I have no pictures of this, but the onsen was very nice. It smelled like fresh wood, and there were many baths to try. The water here is famous in Japan for being the most acidic of any onsen in Japan — almost pH 1! Most of the baths here were labeled 50%, the source water having been watered down, but there was one labeled 100%. I got in and immediately one of my fingers started to hurt. I forgot I had pulled a hangnail earlier, and the water was causing it to sting. One of the ladies nearby accidentally splashed some of the water in her eye and frenziedly grabbed for her towel. Be careful! I think my favorite part of the onsen were the steam boxes. It’s a giant box that you sit in and feels like a sauna, but your head sticks out of the top so you can breathe normally. Big thumbs up from me!