The Sado gold and silver mines

The island that paid for the shogunate, and the history it argues about

Sado lies some 35 kilometres off the Niigata coast, a volcanic island of two parallel mountain ranges where hot water rising through the rock left veins of gold and silver. A tale in the Konjaku Monogatarishū, written down by the late eleventh century, tells of a sand-iron miner from Noto who crossed over with a small boat and some food, came back a month later with gold sand wrapped in cloth, and then vanished, perhaps afraid of being asked where he had found it.

Large-scale mining began in the turmoil of the sixteenth century, after the Tsurushi silver mine was found in 1542, and tunnelling techniques arrived from Iwami. In 1601 the island passed to Tokugawa Ieyasu, and that year a gold vein was found at Kinpokusan. Run directly by the shogunate, the Aikawa mine became one of the largest gold mines in the world. In the early seventeenth century it produced more than 400 kilograms of gold a year, and its silver went into Keichō coins and out to China in exchange for raw silk. As the workings followed the veins under the seabed, water poured in. The shogunate sent convicts and the homeless of Edo to drain the mines, the hardest and most dangerous work there, and a sentence to Sado was a sentence for life.

After 1868 the Meiji government brought in Western engineers, gunpowder, rock drills and pumps, and sank Japan's first Western-style vertical shafts. Mitsubishi bought the mine in 1896, and in 1940, with war driving the demand for gold, it reached its highest output, about 1,500 kilograms a year. That wartime production relied in part on Korean workers. Korean sources say 1,000 to 2,000 Koreans were forced to work at Sado, and in 2015 Japan's ambassador to UNESCO acknowledged the forced labour history. Under colonial rule, an estimated 780,000 Koreans worked in Japanese mines and factories, many in appalling conditions. Mining ended on 31 March 1989.

UNESCO inscribed the Sado Island Gold Mines in 2024, for the way manual mining was carried on and perfected here while machines were spreading elsewhere. South Korea, which had opposed the listing, set aside its protests after Japan promised a full explanation of the history. Japan installed an exhibit acknowledging harsh working conditions, which critics say does not mention forced labour, and South Korean officials boycotted the memorial ceremony held at the mines in November 2024.