Shiga Kogen, Yamanouchi Town, Shimotakai District, Nagano Prefecture
Rating
Cost per person
¥500
The Hiratoko Great Fountain, located along Route 292 in Shiga Kogen, Yamanouchi, Nagano, is a natural hot spring vent that emits powerful steam and a strong sulfurous odor. This unique spot is also known as "Hotaru Onsen" (Firefly Hot Spring) because it's one of the highest altitude habitats for Genji fireflies in Japan. While not a destination in itself, it's a worthwhile stop for a quick photo and sensory experience while driving the scenic Shiga-Kusatsu Kogen Route. Be aware that parking is limited, and the sulfur smell can be intense. The best time to visit is during daylight hours to fully appreciate the surroundings.