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Good money drives out bad: Introduction to the featured section on “The evolution of diverse e-money: Digital-community currencies and cryptocurrencies”*

Abstract This article introduces the special issue featuring “The evolution of diverse e-money: digital-community currencies and cryptocurrencies,” and argue on diversity and evolution of modern money, including community currencies and cryptocurrencies. How such new “currencies” survive through users’ choice in money and what the criteria of such decision are highly critical issues. We contrast the meanings of Gresham’s law “Bad money drives out good,” and Hayek’s principle of choice in money “Good money drives out bad” and show that there are necessary conditions for either Gresham’s law or the principle of choice in money to hold. For the principle of “choice in currency” to function well, both (1) different denominations for the distinction of money in quality, and (2) the non-fixed exchange rates are necessary. Since cryptocurrencies met these conditions, the principle of choice in money began to work. Cryptocurrencies took the test of users’ choice in money in the search for good money but failed to pass the criteria of stability of currency value. Then, digital-community currencies that involve local and community contexts are the next candidates for good money. We observe that two DCCs in Japan, Sarubobo Coin and Kisarazu Coin are currently challenging toward the realization of good money.