Utsuno Cave is a small, hidden-away location in Sano, Tochigi prefecture, that is completely off the beaten path. It's free to enter and likely completely deserted when you visit, being mostly unknown to people outside this part of Tochigi.
This makes for a unique experience and, to reward your efforts in getting there, you'll also be able to witness gorgeous panoramic views of the surrounding valley. Be prepared to make a short 5 minute hike to the summit – granted a few factories/quarries operate in the region, but stunning views can be yours on a good day.
At 165m elevation above ground, the original form of this cave dates back to the Cenozoic era (Tertiary Period) and diluvial epoch (Pleistocene epoch) period, where it developed through the movement of groundwater dissolving the limestone over time. Even now, the stalactites and stalagmites have developed fairly well and have been preserved well. It is thought the Kuzuu region was formed about 250 million years ago from a stratum of predominantly limestone dolomite spread over 8km2 in the region.
The cave itself takes about 10 minutes to explore completely – so is most suitable as a brief stop for travellers passing through the Sano area of Tochigi by car, on their way to other destinations (from Tochigi IC, change to highway 32, towards Kuzuu). Nonetheless, the area can be accessed via a 10 minute bus ride from Kuzuu Station followed by a 3 minute walk.