Sado Kinzan was the most productive mine in Japan, annually producing nearly 400 kg of gold as well as smaller amounts of silver and copper. The mine was in operation throughout the Edo Period and served as a major source of funding for the Tokugawa Shogunate which directly controlled Sado Island and its mines.- Japan Guide
There were 2 routes to choose from, we chose the Edo period mine course since it would be more educational to see they managed the mine way back before industrialization. From the picture, you can observe that they dug really deep and extensively.
The black stripes at the back are when they hit an area with high density of silver and gold, a praying session would be in place where they pray that the ore would be soft enough for quick retrieval.
Then we spent some time in the exhibition hall, looking at models of life outside the mine where the families lives and how they cleaned the ores. A challenge area is also setup where if you can pick up this 12.5kg gold bar with one hand through the glass hole, you would be rewarded with a certificate (No, you can’t take the gold bar with you). Only 1957 persons have succeeded so far over the past 20 years. 😛