Goshaya-yama Site

Wow! Look at all the rocks in the mountains!

Here is the Goshaya-yama Site. Pay attention to the waterways used for placer gold mining and the reservoirs for storing water. There are still piles of unwanted stones from when the mountain was excavated to reach the gold. Meanwhile, the unique shape of the rocks are believed to be the foundation of blacksmith and workshops, built by stacking rubble into squares with one side open. All these remains are well preserved. These remains provide insight into onagashi, the method used to extract placer gold in the area. Onagashi was an unusual technique that was rarely seen elsewhere in Japan.

How exactly was onagashi done?

Onagashi required an enormous amount of water.
1. A large amount of water was collected in a reservoir by digging waterways from several rivers, the water source for the onagashi.
2. The gold-bearing gravels were scraped out of the mountainside by hand. Then, they were washed away with a lot of water from the reservoir.
3. Waste stones that could not be washed away were removed by hand. (The above process was repeated from the first to the 25th or 26th of each month, increasing the concentration of placer gold left at the bottom).
4. The dirt and gold mixture was put into a pan and shaken, and since they weigh different, the placer gold separated and was picked up.
5. At the end of each month, after the placer gold had been collected, the distribution of gold between the miners and the Sado Magistrate's Office was determined at the Mine Administration Office.