A legendary hidden hot spring deep in the mountains, known only to a handful of true enthusiasts. Located in a remote area that is difficult to reach, visitors are rare. It is housed within an old, unmanned shack where guests pay by dropping money into a wooden collection box. The fee is 300 yen per person. There is only one bath, and it is not separated by gender.

It is a place to relax alone or enjoy as a couple. If you encounter other guests, please be considerate and share the space.

While someone clearly maintains the facility, the manager remains a mystery. The water is thick and viscous, and its quality is said to be "extraordinary."

It appears there is a hidden medicinal effect as well.