 Archaeological evidence now shows that the Ban Liang was first issued in the Warring States period by the State of Qin, possibly as early as 378 BC.A remarkable find was some bamboo tablets amongst which were found regulations (drawn up before 242 BC) concerning metal and cloth money.A thousand coins, good and bad mixed, were to be placed in "pen" (baskets or jars) and sealed with the Seal of the Director.