Geonwon Jungbo, Korea's first legal coin and the oldest coin available for viewing today, is assumed to have been minted during the reign of King Seongjong of the Goryeo Dynasty. The Geonwon Jungbo was made using coinage from China's Tang Dynasty as reference. To distinguish between the two coins, those from Goryeo had the letters "Geon, Won, Jung, Bo" on the obverse of the coin, while the reverse showed the words "Eastern Country." These coins were mainly used at state-run taverns and did not find wide usage since grains and cloth were the primary currency forms in the market place.