Toramaru-yama Site and Sasagawa Juhachimai-mura Village

Did people mine for gold before the Aikawa Gold and Silver Mines were established?

Indeed. This place was once the location called Sasagawa Juhachimai-mura Village, a settlement of placer gold miners. The mountain with the reddish outcropping in front of you is the Toramaru-yama site, one of the mining sites of the Nishimikawa Placer Gold Mine, the oldest gold mine in Sado. A place similar to the Nishimikawa Placer Gold Mine is mentioned in the Tales of Times Now Past, which was written in the 12th century during the Heian period. Sasagawa Juhachimai(18-mai)-mura Village got its name in the late 16th century, when placer gold miners contributed 2.9 kilograms, or 18 mai of placer gold in monthly taxes, making the village into a thriving community. The slopes of the Toramaru-yama site, which were stripped bare by placer gold mining, remain barren to this day, offering a glimpse of history.

I wonder how they mined placer gold?

In the past, people would mine placer gold by scraping off the gravel containing the placer gold. Then they would wash away the unwanted dirt with a large amount of water. Finally, they would collect the remaining placer gold left in the "yuriita" pan, and this whole process was called "onagashi". The miners dug several waterways in the surrounding area to get the water they needed for onagashi. The longest of these waterways was said to be over nine kilometers long. In the Edo period, the Sado Magistrate's Office sent mining officials called “Nishimikawa Mine Officials” to the village. They supervised gold mining there until the mine closed in 1872. Even today, the residence of the Kaneko family, who managed the gold mine for many years, and other historical remnants, such as waterways, have been preserved as they appeared in the Edo period pictorial maps.