Sado’s oldest placer gold mine, which is presumed to have appeared in the Heian period’s (794–1195) “Tales of Times Now Past”
The Nishimikawa Placer Gold Mine in the Mano district, located in the southwestern part of Sado, is the oldest placer gold mine in Sado. It is mentioned in the “Tales of Times Now Past” that alluvial gold panning was carried out at this mine, which is believed to have been compiled at the end of the 12th century. In 1589, Uesugi Kagekatsu of Echigo province, the ruler of Sado, redeveloped the Nishimikawa Placer Gold Mine. The alluvial gold produced was offered to Toyotomi Hideyoshi, and around 1593, Oyamazumi-jinja Shrine was built to pray for the safety and prosperity of the mine.
In the latter half of the 16th century, the present-day Sasagawa settlement was called “Sasagawa Juhachimai-mura” (Sasagawa 18-mai Village: mai was a unit used to measure the production of gold and silver before the 17th century) because 18 mai of alluvial gold (approx. 2.9 kg) were paid as tax per month, and it is said that the settlement was very prosperous. In Nishimikawa, the mountains containing alluvial gold were scraped and the gold panned. A method called “Onagashi” (great flow) was used, in which excess stones and dirt were washed away with large amounts of water, and the remaining alluvial gold was collected using panning boards. The water required for Onagashi was obtained by constructing many waterways in the surrounding area, some of which were over 9 km long.
In the Edo period (1603–1868), when the Sado Magistrate’s Office was established in Aikawa, Nishimikawa was positioned as an important mine. A bureaucrat called the Nishimikawa Mine Official was dispatched from the Sado Magistrate’s Office to continue alluvial gold panning, but the volume of mined ore gradually declined, and the mine was closed in 1872.
Subsequently, the people who panned gold changed their means of livelihood to agriculture, and their descendants continue to live in the area even today. The remains of mountains where gold was panned and those of the waterways are still well preserved in the areas around the settlements, and the landscape is almost unchanged from the pictorial maps of the Edo period.
Toramaru-yama Site（Photo by Hoichi Nishiyama）
Toramaru-yama Site
This is the largest mining site in the Nishimikawa Placer Gold Mine. The strata of the mountainside that were scraped for panning alluvial gold are still devoid of vegetation, exposing the red surface of the mountains. (National Historic Site/National Important Cultural Landscape)
Stone-piled work shed site at Goshaya-yama Site
（Photo by Hoichi Nishiyama）
Stone-piled work shed site at Goshaya-yama Site
The Goshaya-yama site is one of the places where alluvial gold panning was carried out in the Edo period using the “Onagashi” method, in which the strata of the mountainside containing alluvial gold were leveled, waterways were built, and water from a reservoir was flushed out all at once to wash down away any excess dirt and stones.
Since there has been no development here since around 1872, when operations were stopped, the alluvial gold panning site, reservoirs and waterways, and the stone-piled work shed site still remain in good condition. This is an important site where visitors can learn how alluvial gold was panned in those days. (National Historic Site/National Important Cultural Landscape)
Sasagawa Settlement
Sasagawa Settlement
This is a village of people who mined alluvial gold. The rows of houses, consisting mainly of traditional wooden houses, still retain the atmosphere of a mining settlement of the time. Large amounts of wastestones left by the Onagashi method were used for the foundations of the houses. (National Important Cultural Landscape)
Kaneko Kanzaburo House (Photo by Monochrome Niigata)
Kaneko Kanzaburo House
This is the residence of the Kaneko family, who served as the mine headmen (managers) of the placer gold mine for generations from the Edo period until the closure of the mine in 1872. In addition to the main building with its thatched roof built in the 19th century, the storehouse, shed, and cow barn remain to this day. (National Historic Site/National Important Cultural Landscape)
Oyamazumi-jinja Shrine（Photo by Hoichi Nishiyama）
Oyamazumi-jinja Shrine
This shrine was built in 1593 to pray for the prosperity and safety of the placer gold mine. The Noh play stage in the shrine’s precincts was built around the late 19th century, and Noh plays were performed here until the 1950s. The Nishimikawa placer gold mine is in an area on the island where Noh plays were very popular, and while the plays were performed as Shinto rituals, they also served as entertainment for the people of the settlement. (National Historic Site/National Important Cultural Landscape)
