Hidden Wonders | The Quarry Behind Tokyo's Most Iconic Structures

The stone used in some of Tokyo's most iconic structures — Tokyo Station, Nihonbashi Bridge, and the Supreme Court of Japan — comes from one of the country's largest quarries. I visited this massive quarry in Kasama City, Ibaraki Prefecture, known locally as the Ishikiri (stone-cutting) Mountain Range, which has been in operation since 1899.

*Due to the hard, water-resistant rock walls, rainwater and spring water have accumulated to create a lake that cannot be found on maps. Kasama City, Ibaraki Prefecture. (©Sankei by Katsuyuki Seki)*

In this tranquil mountain area, towering white rock cliffs marked by quarrying rise like ancient temples. Their majestic forms are reflected in the calm surface of a lake below. The stone belt stretches about 10 kilometers from east to west, 5 kilometers from north to south, and extends 1.5 kilometers underground.

A Majestic Quarry in the Mountains

The white granite quarried here, called "Inada Stone," formed roughly 60 million years ago from cooled magma beneath the ocean floor. Renowned for its exceptional quality, this stone is highly praised for its luster and durability.

*The Inada Stone cut from the rock face weighs about 15 metric tons each. Kasama City, Ibaraki Prefecture. (©Sankei by Katsuyuki Seki)*

Its snow-like surface has earned it the nickname "The White Lady" and it has been used in constructing many of Japan's historical landmarks. For the construction of the National Diet Building, approximately 350 craftsmen worked tirelessly to carve and shape the stones.

*Inada Stone laid out along Gyoko-dori Avenue, connecting Tokyo Station's Marunouchi Central Exit and the Imperial Palace. Chiyoda Ward, Tokyo. (©Sankei by Katsuyuki Seki)*

The Prestige of Inada Stone

Masahiko Kawabata, president of Souseki, a company that has operated in the Ishikiri Mountain Range for 125 years, shared: "The pure white Inada Stone is unparalleled globally. Although it's now rarely used in major construction projects, it continues to be used for shrines, temples, and tombstones, captivating many."

Even today, craftsmen still work in the quarry, producing around 5,000 metric tons of stone annually.

*One of the active quarry sites for Inada Stone. The location has been used for films and promotional videos. Kasama City, Ibaraki Prefecture. (©Sankei by Katsuyuki Seki)*

After visiting the quarry, I headed to Tokyo Station. People hurried along Gyoko-dori Avenue, where gleaming white Inada Stone paves the way toward the Imperial Palace. In the late summer sun, "The White Lady" glowed brilliantly, accentuating the elegance of the red-brick station building, which will mark its 110th anniversary in 2024.

(Read the article in Japanese.)

Author: Katsuyuki Seki, The Sankei Shimbun