was the Tokugawa shogunate's officially sanctioned silver monopoly or silver guild (za)[1] which was created in 1598.[2]
Initially, the Tokugawa shogunate was interested in assuring a consistent value in minted silver coins; and this led to the perceived need for attending to the supply of silver.
This bakufu title identifies a regulatory agency with responsibility for supervising the minting of silver coins and for superintending all silver mines, silver mining and silver-extraction activities in Japan.[3]