Every 2nd and 3rd Sunday of the month by reservation only!
Walk to “Cave X” from the Oya GT office.
Enjoy a 2.5 km exploration tour!
This is a completely original tour led by Oya Green Tourism. The tour will take you to “Cave X”, the remains of a stone quarry that has been closed to the public for a hundred years. You can see the stone quarries as they were worked by hand a hundred years ago. We will proceed through the cave in the dark, each person with a headlight attached to his/her helmet. The darkness, the beams of light, the rock surface of Oya Stone, and the rough stones left behind create a fantastical atmosphere. The path to Cave X is a natural, unspoiled mountain path where moss-covered trees welcome you.
A shrine to a moutain god on the way to Cave X.
Moss-covered trees take you into a world of mystery.
The trail to Cave X. It’s a trail through a pristine mountain landscape.
The view looking outside from Cave X can be enjoyed in all seasons.
Taking a photo in front of a naturally formed heart!
Oya stone is a tuff formed by an undersea volcanic eruption about 15 million years ago. Ishino hana (Stone flower) is a mysterious phenomenon that appears on the surface of the stone in winter. Here in Cave X, where people rarely enter, many Ishino hana appear.
The rock walls of the cave illuminated.


In winter, Ishino hana are everywhere!


A storyteller will guide you and give commentary.
Meet at Oya GT office (Oyamachi 1249) > Proceed to Quarry Site “Cave X” Exploration Tour > Return to Oya GT office
■Dates: 2nd and 3rd Sundays of each month (by appointment only!)
[Time] Approx. 2.5km, 2.5 hours
[Number] 8-20 people
[Fee] 2,500yen ※Boots, helmets, and headlamps are available for rent.
[Itinerary] 10:00 departure → 12:30 finish
13:00 departure → 15:30 finish
[Date] 2nd and 3rd Sundays
[Reservation required] Reservation required at least one week in advance.
[Inquiries and applications]Oya Green Tourism Promotion Council office
1249 Oyamachi,Utsunomiya City,Tochigi
Mail:info@oya-gt.jp