In the pre-Qin period, shells were used as primitive money. As early as the end of the Xia Dynasty, shellfish may have become a medium of exchange. A common tooth shell in Shang Dynasty, the back of which was often ground flat or drilled with holes, was easy to carry, and its scientific name was cargo shell. Shellfish is a kind of shellfish that grows in tropical and subtropical shallow waters. It is small and exquisite, colorful and durable, and has become a favorite ornament of the indigenous residents.

With the development of social economy and the formation of commodity society, natural shellfish has gradually become a universal equivalent of commodity exchange because of its characteristics of moderate size, portability and easy counting. Bei coins take Peng as the unit of measurement, five Bei coins are a string, and two strings are a friend.

Extended data

Before the middle period of Shang Dynasty, the value of Beibi was very high, and it would be a great honor for my lieutenants to get the reward from the Shang King by using Beibi. With the development of commodity economy at that time, the supply of natural shell coins was in short supply, so many imitation shell coins appeared at that time, such as stone shells, bone shells, mussel shells and pine shells. These shell coins are very small, about 1.2 cm ~2.4 cm long.

In the late Shang dynasty, copper coins appeared again, which were also shaped like seashells. Copper shells were unearthed in the tombs of the late Shang Dynasty in Anyang, Henan and Baode, Shanxi, from about 14 BC to 1 1 century BC. The copper shell is the earliest metal coin in China, and there is a kind of gold-coated copper coin used as a large currency.

The unit of measurement of northern currency is Peng. Peng's original meaning refers to a string or two connected northern coins, which gradually evolved into a unit of measurement. Generally, two strings of five shellfish or two strings of ten shellfish are considered as "one friend".

Baidu encyclopedia-babe