Until the end of Meiwa period, not only were used silver coins in western Japan and gold coins in eastern Japan commonly, but also the exchange rate between those coins were flexible and unstable.
明和年間までは、西日本で銀貨、東日本で金貨が一般的に用いられ、しかも両者の為替レートは変動相場制で、不安定だった。