In contrast to the currency issued for use in ancient and early modern Japan, a feature of the currency of that country's medieval period was that the Japanese state did not mint its own coinage but rather imported the entirety of its supply of copper coins from China. An economy based on Chinese coins therefore lasted for 650 years, from the middle of the twelfth century, through the upheavals of the sixteenth century, down to the seventeenth century when the Tokugawa Bakufu once again minted coins. This article outlines the situation of currency and its specific features during this period, paying particular attention to the trend towards the use of credit, in such forms as bills of exchange and promissory notes. In addition, it points out that the medieval Japanese state had absolutely no motivation, either financially or geopolitically, to issue its own currency.