The Former Ōya Quarry: A Hidden Underground Space

Ōya History Museum

(Utsunomiya City, Tochigi)

【Kūkan（空間）】means “space” in English. Space can refer to a continuous, unoccupied area—such as the space on top of a desk, an open area in a park, or even the vast expanse of the universe. However, space is not simply “an empty place.” It is a sense created by boundaries, something that can only be recognized when it is enclosed. Space (Kūkan) can even become a realm that stimulates our sensitivity.

Ōya Town in Tochigi Prefecture is famous for producing a type of stone called Ōya stone. It is a kind of tuff, formed when volcanic ash accumulated in the sea and later rose up through geological activity. Although Tochigi Prefecture is an inland area and has no sea today, in ancient times it once lay beneath the ocean.

This stone is fire-resistant, lightweight, and soft, making it easy to process. It is often used for both interior and exterior building materials. The popularity of Ōya stone has been rising in recent years, with growing demand from hotels and restaurants, as well as increasing orders from overseas for residential use. Its white surface and gritty texture, along with small brown mottled patterns, give it a beautiful appearance. Because of its low thermal conductivity, it is also used for stoves, pizza ovens, and saunas. 

As you enter the town, you will see buildings made of Ōya stone and whitish rock faces exposed, towering into the sky. This is the area where Ōya stone is quarried. Beneath these rocky hills lies a massive underground space beyond imagination. Covering an area of about 20,000 square meters, it is large enough to fit an entire baseball stadium.

This space, quarried continuously for nearly 70 years from 1919 to 1986, is overwhelming to behold. It resembles a gigantic architectural structure, surrounded by vertical stone walls towering 30 meters high. The rocks are illuminated; however, their upper reaches are shrouded in darkness, making the space appear like an ancient hidden temple floating in the void. Standing in the middle of this cavern, one feels how small one’s existence is in the face of the indescribable awe of nature and man-made space.

Taking advantage of this unique atmosphere, the site has been used as a filming location for many movies and dramas. In recent years, “Fly Me to the Saitama” and “Cells at Work!” are among the most famous. It has also been used for music concerts and art exhibitions, making it a popular cultural spot.

In addition to experiencing the atmosphere of this space, there is another reason that makes you want to visit. Inside the quarry, the temperature remains around 8°C year-round, like a natural refrigerator. In summer, it becomes the perfect place to escape the heat outside and enjoy a refreshing coolness.

Please visit the official website of Ōya History Museum.