Korea, Joseon Dynasty. Sang Pyong Tong Bo; 1 Mun. Military Training Command. 1757. (3.75g; 24.0mm). O./ 常 平 寶 通 [Sand p'yong tong bo; Department of Korean Yi Dynasty, currency unit]. R./ 訓 四 大 [(Hun):Hullyondogam Military training Command, (Tae): Great, (Is) Series/Furnace 4]. Mandel#28.5.4. $20