This is one of Takeda Shingen's secret baths, where 500 years ago, the Kai Province lord's samurai warriors healed their wounds after a fight.
It features a special spring called "Shibu Choju-to" (meaning "long life onsen"), which flows naturally to the surface and presents a unique bubbly texture.
Shibu Gotenyu is a ryokan, but most of its baths are open to the general public. If you use the Shibu no Yu trailhead when trekking the Yatsugatake, we recommend you stop over for a relaxing bath on your way back.