From 1678, under the reign of King Sukjong, until late in the Joseon period, the official currency of Joseon was “sangpyeongtongbo.” The rough translation of “sangpyeong” is “constant uniformity,” which indicates the importance of having a currency that maintained a relatively consistent value, unlike earlier barter goods such as cloth or rice. The coins are round and flat, with a square hole in the middle. The name “sangpyeongtongbo” is written on the front, while the back is marked with the abbreviated name of the government office in charge of minting the coins, as well as a single Chinese character, number, and sign.