Since the establishment of the Han Dynasty, the currency has followed half of the Qin Dynasty, but the quality is inferior, and the actual weight is often only eight baht, four baht, or even lighter. Some are as thin as elm couplets and are called "elm pod money". Nobles and wealthy businessmen stole money wantonly, causing currency confusion. The out-of-control of county coins was also one of the reasons for the rebellion of the seven countries during the reign of Emperor Jing of Han Dynasty. After Emperor Wu of the Han Dynasty ascended the throne, on the one hand, out of the need of the central government's economic management and political rule, on the other hand, due to the increasing annual output value brought about by foreign conquest, the national treasury became increasingly embarrassed, so he attached great importance to the monetary system and carried out six monetary reforms successively. The sixth reform carried out "three officials and five baht", which solved the problem of private casting and stolen casting that plagued the finance of the Western Han Dynasty for many years in one fell swoop, which not only stabilized the finance, but also unified the right to coin money delegated to the central government by the Emperor Wudi of the Han Dynasty, so the currency system was stable for a long time. Five baht money became the main form of national coinage from the era of Emperor Wu of the Han Dynasty to the Sui Dynasty for more than 700 years. Five-baht coins with a diameter of about 2 and a weight of about 3.5 grams, which are often unearthed in 0.3 cm Han tombs, are the "three officials and five baht" produced by the sixth monetary reform in the era of Emperor Wu of the Han Dynasty.

From the end of the Western Han Dynasty to the New Dynasty, a series of monetary reforms carried out by Wang Mang once caused confusion in the monetary system. It was not until the early years of the Eastern Han Dynasty that Wang Mang coins gradually withdrew from the historical stage. In the early years of the Western Han Dynasty, the founding emperor Han Taizu (about 202 BC-BC 195) closed the government mint (revised here) to support private casting. Lv Zhi, the widow of Han Taizu, as the Empress Dowager, abolished private coinage in 186 BC. She first issued 5.7 grams (0.20 ounces) of copper coins minted by the government. In BC 182, another coin weighing1.5g (0.053 oz) was issued. Switching to lighter coins caused widespread inflation, so in 175 BC, Emperor Wendi of the Han Dynasty (about 180- 157 BC) issued a decree prohibiting private coinage. They only allow coins weighing 2.6 grams (0.092 ounces). In 144 BC, that is, at the end of the reign of Emperor Han Jing (about 157-14 1 year BC), private coins were abolished again. Despite this, the central and local county governments continue to issue copper coins weighing 2.6 grams (0.092 ounces). It was not until 120 BC that coins were replaced by 1.9 gram (0.067 ounce) copper coins. Other currencies were also issued during the year. When the government collects taxes, it uses embroidered white deer skin with a face value of 400,000 instead of paper money. Emperor Wu of the Han Dynasty also adopted three kinds of silver-tin alloy coins with face values of 3000, 500 and 300 respectively. All coins weigh less than120g (4.2 ounces).

In BC 1 19, the government issued five Thai baht coins weighing 3.2 grams (0. 1 1 ounce); This coin was the standard currency of Tang Wude four years ago (62 1). During Wang Mang's briefly independent new dynasty (AD 9-23), the government adopted several new monetary units in AD 7, 9, 10 and 14 respectively. The market price of these units (including copper knife coins, gold, silver, turtle coins and shell coins) does not match their weight, thus devaluing the coins. After the large-scale civil war eased after the demise of the new dynasty, Emperor Guangwu of Han Dynasty (about 25-57 AD), with the encouragement of Ma Yuan, reintroduced five baht copper coins in 40 AD. Due to the low quality and light weight of coins issued by counties, in 1 13 BC, the central government closed all county mints and gave the central government full responsibility for the coinage of waterways and highways. Although the currency issued by the central government was handed over to the office of Dasinong (one of the nine ministers of the central government) in the early Eastern Han Dynasty, the central government still maintained the monopoly right of currency issuance. Businessmen and small farmers pay property tax and poll tax with coins, and pay land tax for some harvested agricultural products. Farmers earn money by working for rich landlords, working as laborers in industries such as brewing, or selling agricultural products and homemade products in cities and towns. The imperial court of the Han dynasty may think that it is the easiest way to levy taxes with coins, because there is no need to transport taxed goods.

From BC 1 18 to AD 5, the imperial court minted more than 28 billion coins, with an average of 227.6 million (or 227,600) each year. Compared with the Tianbao period of the Tang Dynasty (742-755 AD), 327 million coins were minted every year. In the Song Dynasty (960- 1279), the number of coins was 1045, 3 billion pieces, and 1080, 5.86 billion pieces. Since wages were paid only in cash, coins and cash became the common standards for measuring wealth in the Eastern Han Dynasty. The fifth theory (about 40-85 AD)-The satrap of Shu County (now Sichuan Province) in Han Dynasty described that the wealth of his officials was not converted into land ownership, but the total assets were calculated in cash, with a value of about 654.38+million yuan.

Angus Madison estimated that the gross domestic product (GDP) of the Han Dynasty at that time was calculated at US$ 65,438+US$ 0,990, which was equivalent to US$ 450 per person-this total exceeded the minimum living standard in the 1990s, and it did not change significantly until the end of the 65,438+00 century and the beginning of the Song Dynasty. The widespread circulation of coins and cash made many businessmen rich, and commercial transactions involving hundreds of coins were everywhere at that time. They used their wealth to buy and sell land and become rich landlords. A series of efforts made by the government for cash flow have made a certain social class strong, and this government class has tried its best to suppress it by imposing heavy taxes, imposing high fines, confiscation and price supervision mechanisms.