本沢温泉 雲上の湯

I've been there many times, and each time I can say it's worth it! This hidden hot spring at the foot of Mount Io in the Yatsugatake Mountains is the highest hot spring in Japan that's open year-round. You pay the bathing fee at the reception at Motosawa Onsen, but if you drop in on your way down from Mount Io, you can pay at the inn on your way back. The water is pure white and cloudy, so you can't see anything once you're in. It's also very hot, so it stings. You can't stay in the bath for long, so you'll want to sit on the edge to cool down and then re-enter. The bath's bottom is sandy and rocky, with a place to sit on the river side. Due to its location, there are no changing rooms, so it's a bit intimidating for women. Please consider some kind of safety precaution. You may want to wear bathing attire or a swimsuit, but it will smell like sulfur... and changing after you get out will be difficult. It's on a slope with no place to sit, after all. But it's a great hot spring, and you stay warm for a long time, so it's perfect in the fall!

For the first time in my life, I finally made it to Honzawa Onsen, Japan's highest peak! I paid 1,000 yen for the hot spring at a nearby mountain hut. It was 8 a.m. on a Saturday morning, and it looked like it was going to rain, so no one was there. I'd done a lot of research before coming here, so I knew there wouldn't be any changing rooms, but there really wasn't a place to change, and I truly felt like I'd arrived in a truly remote area. The water is my favorite sulfurous water, with a very high concentration. According to other reviews, it's the second-highest sulfurous spring in Japan, after Manza Onsen. The water was quite hot, but with the outside temperature and a moderate breeze, I was able to enjoy the hot spring for a long time. I love hot springs, and this one, in terms of location, is one of my top three. The sulfur concentration is also high, and these three hot springs—Manza Onsen, Honzawa Onsen, and Tsubame Onsen—are my top three for water quality. It takes two hours to walk here, but I'll definitely come back.

I arrived around noon on Friday, paid at the reception, and headed in. My timing was perfect, and the hot spring was practically all to myself. There were no changing rooms, but I was so tired from hiking that I didn't care about any embarrassment and just bathed in the hot spring right in front of me. The milky white water was surprisingly deep, and I couldn't see the bottom, so I slowly soaked in. The water was hot, so I couldn't stay in for long, but it was cooler outside than on the plains, so I alternated between bathing in the open air and enjoying the hot spring for a long time. There were no fences, so be careful, as you could easily fall into the river. Personally, I felt a tingling sensation on my skin. Even after I got home, I could still smell a faint sulfurous odor. Overall, it was a wonderful hot spring, full of a hidden gem.

Located at an elevation of 2,150m in the Yatsugatake Mountains of Nagano Prefecture, this is Japan's highest open-air bath. It's a two-hour hike from the Motosawa Onsen entrance. Enjoy a dynamic view of the milky sulfur spring water and Mount Io, the highest peak of the Yatsugatake mountain range, standing right before your eyes! The bathing fee is 1,000 yen, and you'll receive a commemorative card. While it's a mixed-gender bath, wearing a swimsuit is optional. (There's no changing room, so I put my swimsuit on from the start. Once we arrived, the bath was all to ourselves, so I ended up taking it off.) The water was quite hot, and my skin turned bright red at first, but Once I got used to it, it felt great, and before I knew it, I was in the bath for over an hour, going in and out. It was an incredibly moving experience!

I used this in June on my way back from climbing Mt. Akadake. The hiking trail from the Koumi side to here isn't easy, but even beginners should be able to manage. It's not crowded, so depending on the day and time of day, you might not pass anyone. After checking in at the lodge, it's another 10-minute climb, but be careful as you'll pass some cliff-like areas. 💦 Since there was no one else there, I was able to relax and enjoy the nature. It has a truly unexplored feel, so I'd love to go again! If you want the view all to yourself, it might be better to aim for a weekday. 🤤