Shimogawara Smelting Site
The Shimogawara site on the outskirts of the town of Omori was one of the most significant local centers for processing silver ore in the early 1600s. Small-scale dressing, smelting, and refining was conducted near mining sites throughout the area during this period—the height of silver production at Iwami Ginzan—but here the entire process was centralized and more advanced than in the mining settlements up on Mt. Sennoyama. This suggests that the Shimogawara site was run directly by the magistrate’s office, which represented the central government at Iwami Ginzan and supervised the silver mine.
Ore brought here from the mine was first dressed by crushing it and sifting through the resulting stones to isolate the silver-containing bits. These were then processed using the haifuki (cupellation) method of refining, which had been introduced to Iwami Ginzan from the Korean peninsula in 1533 and was the key to producing high-quality silver in large quantities. In very simple terms, haifuki involves smelting copper-containing silver ore together with lead. The silver binds to the lead, forming an alloy. This alloy is then placed on a bed of ash and heated to as high as 850°C while bellows are used to keep the mixture oxidized. The other elements of the alloy eventually melt and are absorbed by the ash, leaving only pure silver. This process was conducted around the clock at Shimogawara, where the buildings likely had fire-resistant earthen walls. The structures also featured high ceilings, several windows, and chimneys in every room to let out smoke and sulfurous gases.
