Iwami Ginzan Silver Mine Townscape Tunnels and History

Iwami Ginzan Silver Mine (石見銀山) occupies the Omori district of Oda City and nearby valleys in Shimane Prefecture. Active from the late Sengoku through the early Edo period, it became Japan’s largest silver mine in its heyday and is now closed; its surviving tunnels, townscape and managed woodlands were inscribed on the UNESCO World Heritage List in 2007.

Arrival and visitor centres

The main public orientation points for the site are clustered around the historic Omori town and the eastern part of the Ginzan Sakunouchi area. A dedicated Iwami Ginzan World Heritage Centre opened on 20 October 2008 in the eastern sector of the Ginzan Sakunouchi property to provide interpretation and overview information. Separately, the Iwami Ginzan Museum occupies a Meiji-era building first opened in 1976; it was reworked and reopened on 1 April 2022 with a renewed focus on the eighteenth-nineteenth century daikan, presenting the museum under the informal secondary name “Imo Daikan Museum.” The Kumagai family residence in Omori, an Important Cultural Property, is among historic buildings whose interiors are accessible to visitors.

Getting there

By car: follow National Route 9 after joining the San’in Expressway at the Izumo IC or the Gotsu (江津) IC. By public transport: from Izumo Airport a limousine bus serves Izumo-shi Station in about 30 minutes. From Izumo-shi Station ordinary JR trains take approximately 40 minutes to JR Ōda Station and approximately 55 minutes to Nima Station. From either Ōda Station or Nima Station, Iwami Kotsu route buses provide onward service toward the Omori and Ginzan areas.

Historic townscape and built heritage

Iwami Ginzan has layered designations: the site was protected as a national Historic Site in 1969 and the Omori Ginzan district was selected in 1987 as an Important Preservation District for a Group of Traditional Buildings (mining town type). The UNESCO nomination bundles the mine workings and the mining townscape with related infrastructure and port towns. Component elements named in the inscription include Ginzan Sakunouchi, Omori-Ginzan, the Daikansho (the former magistrate office now associated with the museum), the Kumagai family house (an Important Cultural Property), Rakan-ji with its five-hundred rakan statues, the Miyanomae district and several castle sites. The ports and routes used for shipment—Tomogaura, Okidomari and Yunotsu—are also part of the registered set of properties.

Mine workings and industrial remains

More than seven hundred mine tunnels and drainage workings, called “mabu” in local usage, had been identified by 2015. Principal tunnel groups named in site documentation include the Kamaya mabu, Ryugenji mabu, Okubo mabu and the so-called Permanent (Eikyū) workings. Okubo mabu was developed across the Edo and Meiji periods; it was originally hand‑dug, later enlarged with drills, and wooden rails and small wagons were introduced for ore transport. Below Okubo mabu lies the Kinsei drainage adit, excavated in the Meiji period, which is connected to Okubo by flighted steps visible within the workings. Waste rock (zuri) from excavation was used locally to fill valleys and create small areas of flat land. Before electric lighting, miners commonly used a lamp fashioned from a turban-shell (sazae) called a ratō; that lamp form long belonged to local visual culture.

History and economic role

A local chronicle records a legend of discovery in 1309, and small-scale surface mining was conducted in early phases. Large-scale redevelopment began in the early 16th century: a leading merchant from Hakata undertook systematic extraction from 1527 with the support of local authorities and neighbouring mine operators. Control of the silver resources passed repeatedly among regional powers in the sixteenth century—the Ouchi, Amago and Mōri clans all contested the mine—until the Mōri consolidated control in the 1560s and presented the mine to the court as imperial domain. Documentary returns show the scale of output: a 1581 record gives a levy (noshodaka) for the Omori mine of 33,072 kan of copper-silver equivalent, shown in the source material as 3,652 silver pieces; and in the early seventeenth century the Tokugawa administration’s rapid development of the mine led to a reported delivery of some 4,000–5,000 kan of silver in 1602.

Iwami Ginzan was central to Japan’s silver economy in the 16th and 17th centuries. Contemporary estimates cited in the documentation put Japan’s annual silver production at around 200 tonnes, with Iwami’s share around 38 tonnes (about 10,000 kan). Refined silver from the mine—known in contemporary foreign trade as “Soma” silver after the old local placename—was worked into the flat, weight‑based currency pieces such as Sekishu chōgin and later the Keichō chōgin used widely for domestic transactions and for export trade with Ming China and European traders.

World Heritage inscription, conservation and tourism

Japan placed the Iwami Ginzan nomination on the UNESCO tentative list in 2001 and submitted a full nomination in January 2006. At the 31st World Heritage Committee meeting in Christchurch the committee decided in the session of 28 June 2007 to inscribe the site as a UNESCO World Heritage cultural property; the inscription was formalised on 2 July 2007. ICOMOS had earlier proposed a deferral, prompting Japan to supply a substantial English language supplementary dossier emphasising the mine’s long history of woodland management and its integrated landscape. The committee recognised the site against criteria (2), (3) and (5). ICOMOS and the committee also recorded follow-up needs: further study of the cultural landscape, archaeological investigation of unexcavated remains, protection of wooded site cover, and management of waterborne mine drainage and infrastructure impacts. A small boundary amendment was accepted in 2010: Omori’s preservation area was extended (in 2007 selection documents Omori expanded from 32.8 hectares to 83.62 hectares) and Yunotsu’s municipal preservation area was increased in 2009, among other adjustments to improve the coverage of landscape and port elements.

Local stakeholders set up collaborative governance arrangements in advance of inscription: a citizen‑led Iwami Ginzan collaborative meeting met in 2004 to deliberate conservation and use, and a maintenance and conservation liaison group formed in 2005 to coordinate volunteer and civic activities. Visitor numbers rose sharply after inscription (around 810,000 visitors in 2008), and local authorities took measures—such as restrictions on direct bus access—that affected visitor flows; local groups in the documentation judged a sustainable visitor range to be roughly 300,000–400,000 per year and emphasised the role of guides for interpreting the complex industrial heritage.

FAQ

When was Iwami Ginzan inscribed as a UNESCO World Heritage Site?

The World Heritage Committee decided inscription on 28 June 2007 and the site was formally registered on 2 July 2007.

Where is the mine located?

The mine is centred on the Omori area of Oda City and extends into nearby Nima and Yunotsu in Shimane Prefecture.

How extensive are the surviving mine tunnels?

By 2015 more than 700 mine tunnels and drainage workings (mabu) had been identified.

When did the mine reach its peak production?

The mine’s heyday ran from the late Sengoku period into the early Edo period, with peak deliveries recorded around the early 1600s.