UTSUNOMIYA - One step inside the former quarry site at the Oya History Museum in Utsunomiya and you will feel as if you are exploring ancient ruins.
Oya stone, a type of tuff stone that can be seen across the city's Oya district, used to be quarried at the site.
Lured by the prospect of cold air, I went down a dark set of stairs at the old quarry and found myself in a vast underground space where there are a group of stone pillars, each one 10 meters wide.
Created as a result of about 70 years of drilling that started in 1919, the underground space is about 10 meters high and has an area of about 20,000 square meters - enough floor space for an entire baseball stadium. The temperature at 30 meters below ground is about 13 C even in midsummer.
The white stone walls are illuminated by red and blue lights, and lines made in the course of drilling work trace geometric patterns on the walls. Visitors admired the view saying, "It's so mysterious."
Until around the 1960s, the stonecutting work was done by hand. To cut out a slab of stone measuring 90 by 30 by 18 centimeters, workers had to strike the stone with a pick about 4,000 times.
Each worker could quarry about 10 stones per day, on average, and there reportedly were workers called kodashi who specialised in carrying stones weighing about 100 kilograms on their shoulders out of the quarry site.
Looking up, the ceiling was black, unlike the white walls.
"The ceiling was blackened by soot because the inside was warmed by fire," Hiroo Suzuki, 62, the director of the museum, said.
The museum also explains that the Oya quarry site was used as an underground military plant in the final days of World War II.
Oya stone was used to build the former main hall of the Imperial Hotel, which did not collapse even in the Great Kanto Earthquake, making the stone a sought-after material for various other buildings.
However, with the advent of concrete, the quarrying industry declined. The 119 stone drilling companies that existed around 1970 have now fallen to nine, and among the more than 200 stone quarry sites in the city, only nine are currently used.
However, as a large number of people are attracted by the fantastical space created over a long period of time, the former quarry site is now used as a venue for concerts and exhibitions, and promotion videos of famous artists and movies have been filmed at the site.
At a different former quarry site outside the museum, a boat cruising tour of a huge underground lake, which is believed to have been created by rainwater accumulating there, began in April last year. Underground spaces in the Oya district are again bustling with activity.
The Oya History Museum exhibits drilling tools and explains the history of Oya stone. At its underground facility, visitors need to be careful about their shoes and clothes as condensation from the cooling of humid air makes the facility's floor wet from around June to October. Around the Oya district you may see oddly shaped rocks, as well as stores and warehouses built of stone. People who hope to join the underground boat cruise need to apply at Chiikikachi Keikaku (028) 689-8782.
Oya History Museum
Address: 909 Oyamachi, Utsunomiya
Opening hours: 9 a.m. to 5 p.m. (The entrance gate closes at 4:30 p.m.) The museum is closed during the year-end and New Year holidays and some other periods.
Admission: 700 yen (S$3.80) (350 yen for middle school students and younger)
For details, call (028) 652-1232.