Money has many names. Today, different terms are used for the monetary units of Korea, China and Japan-won, yuan and yen-but each of these words comes from the Chinese character ‘Won(圓), meaning “circle”. This implies that money in the form of coins is round and therefore circulates. Money is basically an instrument of exchange, storage and measurement of value. It must be accepted as a medium of exchange in markets and remain stable in value, and someone has to be responsible for controlling the volume of money in circulation. Money must also be consistent in terms of the quality of materials used to make it, and remain pure even when when melted to be divided or melded together. Currency is closely tied to the political, economic and social environment. Just as living creatures become extint when they fail to adapt, currencies that fail to serve their purposes disappear and are replaced by new types of money. In this way, currency has evolved throughout history.