Hamayu Sanso

The bath is a comfortable temperature, around 41°C, so you can really relax in it. Hamayuso's spring water is brown but has no smell, quite different from Aimagagawa Onsen in Kurabuchi. Aimagagawa Kleingarten and Aimagagawa Seseragi no Yu have brown water with an oily smell. The downside is there's no outdoor bath. You can see the forest, but the view isn't particularly striking. After bathing, you can have Yokosuka Navy Curry. I asked the staff, and they said it's homemade rather than pre-packaged. I've never had authentic Navy curry, but I thought it was delicious!

The bath water was just the right temperature and very pleasant to soak in. It's a reddish-brown, iron-rich spring, circulated with added water and chlorine sterilization. If chlorine bothers you, I'd suggest showering after your bath. There were few overnight guests, so I had the bath to myself in the morning and evening. The place is a huge facility, which surprised me. It seems to have been a Yokosuka City facility in the past, with a gymnasium, and apparently hosts youth training camps. I visited on a weekday, when the bathhouse was busy with older people stopping by for a soak after mountain climbing. It's on National Route 406 on the way to Kita-Karuizawa, where the road starts climbing more steeply from here.

The brown spring water is so deep you can't see the bottom, and it warms you right through. They say this iron-containing spring is the only one of its kind in Gunma, which is known for its hot springs. The spacious hotel was well maintained, and our room was spotless. We came as a couple for one night in late December. We had lunch at the hotel restaurant and hoped to try the King of Pasta menu. There was time before check-in, so we asked the front desk if we could wait by the entrance. When they told us our room was ready, they kindly let us check in early, though I won't say what time. We had booked the top Joshu Wagyu course for dinner, which included Ginhikari beef. It was delicious, and my husband and I especially liked the wagyu's rich flavor and tenderness. The local Kurabuchi koshihikari rice was so good we had several bowls, lol. Breakfast was a healthy buffet made with local ingredients, and every dish was tasty enough that we went back for seconds. I don't have any particular complaints, though the layout means every room opens onto the same hallway. Noise outside carries through just one door, which could bother light sleepers. The doors also rattled quite often, probably because of the air pressure, lol. With the nature, good food, warm service, and reasonable price, I thought it was a great hotel.

The day-use hot spring seems like a good option. It's an indoor bath only, but the water circulates well and feels hygienic. There's also a campfire stand in the courtyard, and the facility seems to have potential, though it doesn't really make use of those features. As a hotel, it doesn't seem aimed at the general public. It feels more like a youth center or training camp, and there were lots of high school students staying there. The evening meals were especially disappointing. With a 40-minute drive up mountain roads from places like Karuizawa and no nearby restaurants, it's not somewhere I'd pick as a regular hotel. It could work for business use as a slightly upscale business hotel.