Iwami Ginzan

A third of the world’s silver once came through these hills

Iwami Ginzan lies in the hills above Ōda in Shimane Prefecture, in the southwest of Honshu, a cluster of mountains rising to 600 metres between deep river valleys. The merchant Kamiya Jutei discovered and developed the mine in 1526, and later brought in a Korean way of refining silver that became the haifukiho method, part of the Asian cupellation technique that had travelled from China through Korea. The work was done by numerous small, labour-intensive businesses using manual techniques, covering everything from digging to refining.

At its peak in the early 1600s the mine produced about 38 tonnes of silver a year, when Japan as a whole produced about 200 tonnes, then a third of the world's output. The silver was of very high quality and was sold abroad as Soma silver, after the village of Sama where the mine stood, and it carried the highest trading credit in East Asia. Coins struck from it served as currency within Japan and in trade with China, Portugal and the Netherlands, and in Europe and China the mine was compared with Potosí. Maps of the period marked the area as the Silver Mine Kingdom.

Warlords fought over it until the Tokugawa shogunate won control in 1600, after the Battle of Sekigahara, and closed it in with fences and barricades of pine. Yamabuki Castle stood at the centre of the complex. Production fell in the 19th century, as Japan's isolation kept out European industrial methods and the commercial ore ran out; copper took over, and the mine closed in 1923. Controlled logging meant less deforestation, erosion and pollution than a mine that size usually causes, and forest has since reclaimed most of the old workings.

UNESCO inscribed the Iwami Ginzan Silver Mine and its Cultural Landscape in 2007, after ICOMOS had first recommended deferring it. The site takes in some 600 pits and shafts, smelting and refining sites, three 16th-century castles built to protect the mines, transport routes to the coast, and three port towns, Tomogaura, Okidomari and Yunotsu, from which silver was shipped to Korea and China. The mining town of Ōmori, protected since 1969, keeps traditional wooden buildings from the 17th to 20th centuries, among them the Kumagai family house. The city's own itinerary runs from the World Heritage Center to the Shimizudani smelter ruins and the Ryugenji Mabu and Okubo Mabu mine tunnels, through Ōmori to the 500 arhats of Rakan-ji, then out to Okidomari and Yunotsu for an evening of Iwami kagura.