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.

Tochigi

The Former Ōya Quarry: A Hidden Underground Space