Money is a special commodity used for barter exchange. Everyone knows that the earliest money was shells. As human beings develop, the "money" used for barter exchange must also develop. This requires meeting at least two requirements.
The first is that it is easy to carry and store. This requires that "money" should not be afraid of falling or hiding, be able to withstand the test of various extreme environments, and be easy to circulate.
The second is that with the establishment of the country and political power, it must carry out corresponding functions and represent national authority and culture.
It is precisely because of these two major needs that copper, a rich metal, became the first choice for making coins. Gold and silver are both stored in small quantities. It can only afford the exchange of bulk goods.
Since copper coins are selected to represent official authority and the will of the country, when the coins are made, they must reflect the external aesthetics given by the state power and the internal cultural heritage.
First, the sky is round and the place is round
As we all know, in Chinese culture, there is a concept of a round sky and a round place. Therefore, it must be reflected on coins. Therefore, ancient copper coins are almost all round, which not only meets the requirements of portability and safety, but also reflects the concept of "round sky".
There is a square hole in the middle, which represents the "place" and is also convenient for connecting with ropes.
Second, a gentleman is round on the outside and square on the inside
This point is derived from the round sky and the square place. It is a reminder of ancient etiquette and personal cultivation, and is a manifestation of "virtue". A person's conduct in life can be tactful and treacherous in rhetoric and so on, with the aim of not hurting each other's harmony, but the heart must be firm and sharp, that is, there must be a bottom line, good and evil must be clear, and cannot be vague.
For example, Confucius said: A gentleman can bully others. That is, he is too upright in his conduct and can easily be taken advantage of.
Money belongs to "profit". The so-called gentleman values ??righteousness over profit. Therefore, the coins follow the outer circle and the inner square, reflecting this cultural connotation. At the same time, since ancient times was an agricultural civilization and was based on agriculture, naturally this connotation is in line with the needs of the country.
Roughly because of these two points, ancient coins are all round on the outside and square on the inside. It is easy to carry and store, and at the same time reflects the characteristics of ancient Chinese culture.