China is one of the earliest countries to use money in the world, with a history of 5,000 years. In the process of its formation and development, China's ancient currency experienced five major changes:

1, the evolution from natural currency to artificial currency. Shells were the earliest currency in China, and shells were used as currency in Shang Dynasty. In China's Chinese characters, most of the words related to value come from "Bei". With the development of commodity exchange, the demand for money is increasing, and shells can no longer meet people's needs. Shang people began to imitate seashells with copper. The appearance of copper coins is a major evolution from natural currency to artificial currency in the ancient currency history of China. With the extensive use of artificial coins, seashells, a natural currency, gradually withdrew from the currency stage in China.

2. Evolution from messy shape to unified shape. From the appearance of copper coins in Shang Dynasty to the Warring States Period, there were many forms of China currency. During the Warring States period, not only countries made their own money, but all regions of a vassal state also made their own money. It is famous for Zhao's shovel coins, Qi's knife coins, Qin's round hole coins and Chu's ant nose coins. After Qin unified China, Qin Shihuang promulgated the earliest monetary law in China in 2 10 BC, "taking Qin coins as the world's currency", which stipulated that the whole country should use Qin's square and semi-written language. The unification of currency ended the chaotic state of China's ancient currency with different forms and different weights, which was a major evolution from chaotic form to normative form in the ancient history of China's currency. The shape of this circular square hole determined by Qin Banliang Qian continued until the early Republic of China.

3. Evolution from local currency to central currency. At the beginning of Han Dynasty, counties were allowed to cast money freely. According to the Records of Hanshu Foodstuffs, Wendi "made people make money besides stealing", so "stealing is like a cloud". This not only caused currency confusion, but also made dajia, a wealthy businessman, manipulate the right to coin money, making him richer than the emperor. In 65438 BC+065438 BC+03 BC, Emperor Wu of the Han Dynasty recovered the right to coin coins in counties and counties, and the central government unified the casting of five baht, which became the only legal tender at that time. From then on, it was decided that the central government would manage the casting and distribution of coins in a unified way, which was a major evolution from local coins to central coins in the ancient currency history of China. Since then, coins of past dynasties have been directly managed by the central government. The return of the right to coin to the central government played an important role in stabilizing the political situation and economic development of the dynasties.

4. The evolution from literature weight to Bao Tong and Yuanbao. Coins minted since the Qin and Han Dynasties usually clearly indicate the weight of Qian Wen currency, such as "half a tael" and "five baht" (24 baht is one tael). In the fourth year of Wude in Tang Gaozu (62 1), Li Yuan decided to reform the currency system, abolish ancient coins with different weights, take the meaning of "creating the world" and uniformly cast "Kaiyuan Bao Tong" money. "Kaiyuan Bao Tong" is a change of the old system in Qin and Han Dynasties, and Qian Wen didn't pay attention to weight, which is the evolution of the ancient currency in China from the weight of certificates to Bao Tong and Yuanbao. "Kaiyuan Bao Tong" coin is the earliest Bao Tong coin in China. Since then, China's copper coins no longer take Qian Wen as the standard weight, but are commensurate with Bao Tong and Yuanbao, and have been used until the "Bao Tong of the Republic of China" after the Revolution of 1911.

5. Evolution from metal money to paper money. During the Northern Song Dynasty, with the development of exchange, currency circulation increased. When Emperor Taizong of the Northern Song Dynasty was in power, he minted 800,000 coins every year, and then gradually increased. Due to the shortage of copper materials for casting coins, the government has cast a large number of iron coins in some areas to make up for the shortage of copper coins. According to "History of Song Dynasty", the total amount of cast iron money in Sichuan at that time weighed 25 Jin 82 Liang. In Sichuan, you have to pay 130 Jin of iron to buy a piece of silk. Iron money is so cumbersome and inconvenient that the paper money "Jiaozi" printed in the Northern Song Dynasty came into being in Sichuan. In Song Zhenzong, with the permission of the government, it is run by 16 wealthy families in Chengdu. The appearance of "Jiaozi" is an important evolution from metal money to paper money in the ancient currency history of China. Jiaozi is not only the earliest paper money in China, but also the earliest paper money in the world.