in the early edo period , hyodo kahei (currency valued by weight ) such as cupellated gold and silver which had hallmark on metal , was circulated widely , and bakufu banned cupellation of gold and silver (isolation and ore refining ) in feudal lord ' s territories around the country in 1668 , controlling major gold and silver mines as tenryo (a shogunal demesne ) under the direct control of bakufu to organize territory currency like hyodo kahei and unify them into keicho gold and silver . 江戸時代初期は依然として、灰吹金および灰吹銀といった地金に極印を打った秤量貨幣が広く通用しており、幕府はこのような領国貨幣を整理して、慶長金銀に統一するため、各地の有力金銀鉱山を幕府直轄の天領として管理し、寛文8年(1668年)年頃には諸国での金銀吹分け（分離・精錬）を禁止した。
