Oya Temple is located a short distance outside Utsunomiya. Its interesting because of the giant statue and the underground caverns.
As you get close you will start seeing shops selling local rock and various builds made out of it. If I had to guess its not very good rock to make things out of because its very light and porous. But the statue is pretty neat and its a good place to visit.
First stop is the statue. If you look closely around the statue you can see areas where big arches have been made and collapsed. Near the statue is a small temple with some nice garden which you must pay a small fee to enter. There is a very old human skeleton that they found in the area on display.
Some distance away is our favorite part. Huge underground caverns made when the excavated rock in the area. Also there is an interesting display where you can compare the local rock with other kinds of rock.
Its a good area for a short visit if you are in Utsunomiya.