History tells us that neither government decree nor intrinsic content can determine the value of currencies. However true this statement is, though, it is not at all clear who actually made that determination. It is easy to say theoretically that the market decides the price of currencies, but it is not so easy actually to mark the boundaries of the market and identify those who were influential in valuing the currency. Thus, the question remains unanswered. Nevertheless, certain historical facts concerning medieval Japan discovered by Hiroyuki Honda in the following paper furnish us with two important implications regarding it.