HKMAL collection
China, Qing Dynasty, Dao Guang (道光), 1821-1850, Dao Guang Tong Bao (道光通寶), "BOO YUWAN"/ Board of Works mint (寶源局), Peking. 4.51g, 22.63mm, Brass. 母錢/mu qian (seed or mother coin).	Asia China 1821