Korea, Joseon Dynasty. Sang Pyong Tong Bo; 1 Mun. Government Tithe Office. 1807 AD. (3.65g; 23.2mm). O./ 常 平 寶 通 [Sang p'yong tong bo; Department of Korean Yi Dynasty, currency unit]. R./ 均 九 (Kyun): Government Tithe Office, (Jiu) Series 9]. Mandel#15.1.9 $20