周世宗
Copper mining in the north was heavily disrupted by the constant warfare of the Five Dynasties and Ten Kingdoms era. In consequence bronze coins became scarce. The situation became dire in northern China. In 955 the Later Zhou Emperor Chai Rong banned the possession of bronze utensils upon pain of death. The Southern Tang and their neighbors minted coinage from clay, iron, or lead. These coins for domestic circulation (despite having minimal value intrinsically) and to prevent the export of precious bronze coinage to neighboring states.