sentences:  Additionally, silver vases called "ŭnbyŏng" were widely used and circulated as a currency among the aristocracy of Goryeo.It was not until the beginning of the Joseon period that copper coins called "mun" were minted for wide circulation.Jeohwa (저화/楮貨), which was made of standardized mulberry-bark paper early in the Joseon period, become the first legal paper money and was used as a medium of exchange in place of coins until it disappeared in the early 16th century.