Pei Bi Dang Jin 350 BC - 250 BC

The Pei Bi Dang Jin coin was used as a form of currency during the Warring States period in ancient China, and it's interesting to note that the coin was made of bronze, which was a valuable resource at the time. The use of bronze in coinage was a significant innovation in the history of currency, as it was more durable and had a higher value than other materials used in earlier forms of currency, such as cowry shells or bartering systems. The Pei Bi Dang Jin coin's use of bronze helped to establish it as a widely accepted and trusted form of currency, and it played an important role in facilitating trade and commerce during this time period.