In the Edo period, the currency value of Hyoryo ginka (the silver coin used as the currency by weight) depended on its weight, and in 1700, 60 monme of chogin (silver coin) was officially equalized in value with 1 ryo of koban (former Japanese gold coin of oval shape), however, it was actually floating rate by the market economy.
江戸時代には秤量銀貨の実測値が通貨単位として使用され、元禄13年（1700年）に丁銀60匁は小判1両に相当すると公定されたが、実態は市場経済による変動相場であった。