The Output of Copper and Coinage in the 18th Century Sado

Abstract

Coins were minted in Sado during the years from 1714 to 1741 and also from 1771 to 1781.
In the first half of the 18th century, especially from 1738, for 7 or 8 years, on, coinage was thriving. It was due to the rise in monetary value caused by recoinage and to the shortage of volume of coins in circulation caused by laying up. The case was the same with Sado, and mineworkers were so much hindered from working at gold and silver mines, that necessity for coinage was greatly cried for.
Since 1714, coins were minted first by Edo merchants and then by Aikawa merchants, but the coinage could not be continued any more than 2 years and a half.
Under the administration of Sado-bugyo-sho (Magistrate Office) during the years from 1717 to 1734, it was planned to mint coins to the amount of 10, 000kan a year (in fact, 9, 600kan, according to the customary rule to pass 96mon for 100mon [ku-roku-ho: ninety six-rule] observed at that time), but real output was only 60 percent or less then 60 percent of the planned amount.
In 1734, an application for coinage made by Aikawa merchants was admitted, but their program did not make good progress as prearranged owing to a shortage of copper. Thus, in 1740, they had to take a temporary expedience to mint iron coins.
During the years from 1771 to 1781, five Aikawa merchants carried forward a plan to mint coins to the amount of 10, 000kan a year. Though until that time the copper from Sado had exclusively been used as a material, together with tin and lead, for coinage, on that occasion it was per-minted to purchase copper from Osaka-doza (the Osaka Copper Refinement, Collection and Delivery Agency). But actual amount of coinage was as before less than 60 percent of the planned one.
The copper production in Sado was known as early as in the middle of the 17th century, and until the middle of the 18th century, the Tsurushi pit (Sawada-town) and later the Torigoe pit belonging to the Aikawa mine ranked among the principal copper mining places.
Around 1714, when coinage started, the output of copper from the Tsurushi pit was said to have reached 43, 750kin a year, but after that year on the output began to decrease. After the suspension of coinage in Sado, copper was sold to Osaka-doza. We can give almost all the figures of annual output of copper of those days, from which we understand that 38, 665kin in 1797 was maximum.
The copper from Sado was called Shibori-do (unwrought copper), from which Haifuki-gin (refined silver) and Suji-kin (refined gold) were obtained by means of Namban-buki (smelting) method. In Sado, Shibori-do was usually refined into re-Sibori-do by the same method of Namban-buki, and was sold to Osaka-doza until about 1818. But probably with the smelting process in Sado it was not enough to fill the need of Osaka-doza, because it was usual that Shibori-do and re-Shibori-do from Sado were refined again at Osaka-smelter.