"So if we want to solve the problem of copper coins being inconvenient to carry, then we can launch a new currency, as long as it can be guaranteed to be exchanged for the equivalent value of gold." Zhang Nan said.

"New currency?" Everyone said in unison.

"That's right, it's a new currency, a currency that is easy to carry and easy to trade, in fact, I don't need to say, you adults should also know that when businessmen make transactions with relatively large amounts, they will not carry so many copper coins, and after the transaction is completed, they will generally have a voucher representing the amount of their transaction, and with this voucher, you can get the agreed money." Zhang Nan said.

The voucher that Zhang Nan said in his mouth is the original banknote, which is the so-called "Jiaozi".

In the early years of the Northern Song Dynasty, Sichuan used iron money, which was worth a small weight, and it took 90 to 100 catties of iron money to buy a silk. Inconvenient circulation. As a result, merchants issued a type of paper money, called Jiaozi, which was circulated in place of iron money.

Thirty dollars will be deducted for each cash-out. Sixteen wealthy businessmen in Chengdu opened Jiaozi shops for the purpose of printing, issuing and operating the exchange business of copper coins and Jiaozi, which opened the precursor of private finance. Every year when the silkworms, rice, and wheat are about to ripen, they use the same color of paper to print jiaozi. This is the earliest paper money.

"Qingquan, you mean to make this voucher into currency?" Cui Shao asked.

"That's right, that's what I mean, but if this thing is made, it's not a certificate, it's a paper money." Zhang Nan said with a smile.

"Banknotes?" Again, the crowd spoke in unison.

"It's paper money, we now have Datang's papermaking technology is mature, we can make paper that can't be imitated by others, we only need to use this paper to make paper money, we can make the smallest face value into consistent money, and when we use copper money in the future, we don't need to take consistent money, just need a piece of paper, which is consistent money." Zhang Nan said with a smile.

"Just a piece of paper?" Li Er looked a little puzzled, although Zhang Nan had already explained to him clearly about the value of money, but Li Er still couldn't accept for a while that a piece of paper had inexplicably become consistent money.

"Yes, just need a piece of paper, we can also set different denominations, such as 20 Wen, 50 Wen, 100 Wen, 500 Wen, consistent money, or a larger denomination, of course, this matter of setting the face value only needs to be left to the household department to consider."

After listening to Zhang Nan's words, Cui Shao almost vomited blood, Zhang Nan said a lot of words, and finally kicked the ball under the feet of the household.

"That's a good idea." Li Er thought about it and said.

"But Qingquan, how can you guarantee that this paper money must be better than copper money? At least not in my opinion. After thinking about it, the eldest grandson Wuji put forward his different opinions.

"Oh? The eldest grandson can directly say that there is something wrong with him. Zhang Nan said with a smile.

"In the old man's opinion, this banknote has nothing to do except if it can be reset, you think, this banknote is made of paper, although it is more convenient to carry when a large amount of money is said, but it is not too easy to preserve." The eldest grandson Wuji said.

"That's right, that's right. If you use paper to make money, not only is it not easy to preserve, but it will be relatively easier to imitate? Fang Xuanling also spoke.

"Imitation? No, no, no, Master Fang, you have been thinking too much, and there is no possibility of imitation. Zhang Nan said with a smile.

"Oh? Are you so sure of Qingquan? Li Er asked.

"That's right, the minister is so sure, the minister dares to ask the emperor, why is there no one copying the copper coins we use now?" Zhang Nan looked at Li Er and asked.

"Because they don't dare." Li Erdao.

"That's right, it's because they don't dare, our "Tang Law" clearly stipulates that the people are prohibited from minting money privately, and if someone mints money privately, it is a violation of the "Tang Law". But the emperor, you should pay attention to one thing, because of the "Tang Law", so no one in the people dares to mint money privately, but this does not mean that the people do not have this technology to mint money. Zhang Nan said.

"And Your Majesty, are you really sure that there is no circulation of counterfeit money in Datang? I don't think so, the emperor can't guarantee this, right? Zhang Nan said with a smile.

Indeed, as Zhang Nan said, even Comrade Li Er, the first emperor of the ages, cannot guarantee that there is no counterfeit currency circulating in the territory of Datang, because compared with paper money, copper money counterfeiting will be easier.

The easiest way to do this is to reduce the weight of the coin.

It is perfectly feasible to dissolve twelve copper coins or eleven copper coins out of copper water from ten copper coins. And this weight is not felt at all in the hands of ordinary people.

If you want to make it more like a little bit and solve the weight problem, then you can add cheaper metal to it, and the cost is not very high.

In the early years of the Western Han Dynasty, there was a serious shortage of currency, and Han Gaozu implemented pod money, which nominally weighed 12 baht, but in fact it was only 3 baht. When Dong Zhuo was in power, he changed the five-baht coin to one baht, and the currency depreciated four or five times at once. Some people melt the 12-baht money and make it into a three-baht pod as a 12-baht coin, and the currency in the market varies in weight and size.

Due to the limited production of copper, during the Northern Song Dynasty, the official price of mineral products was: copper per catty of about 200 wen, tin per catty of 35 wen, lead per catty of 18 wen, it can be seen that the price of copper is about six times that of tin, 11 times that of lead.

There are countless examples of this kind of counterfeiting in the long history of China, and almost every dynasty that used copper coins as currency can see such records, and there seems to be no better solution to the problem of currency counterfeiting except for the introduction of strict laws.

Of course, in addition to reducing weight and doping with other metals, there were cases of small money being flattened and used as big money during the Song Renzong period.

During the time of Renzong, there were constant troubles, and the demand for military spending was huge, so he often minted a lot of money, and cast three small copper coins into a big coin worth ten dollars.

After Emperor Huizong of the Song Dynasty succeeded to the throne, in order to make up for the fiscal deficit caused by huge expenditures, he even issued currency indiscriminately, which eventually led to inflation. In the currency circulating in the Song and Jin dynasties, it is common to see small flat coins that were mixed into the strings of money to pass off as large coins after the area was expanded.

Therefore, for the Tang Dynasty, Zhang Nan does not think that the Tang Dynasty has anything advanced compared to other dynasties in terms of monetary management. Therefore, Zhang Nan also believes that there is also a situation of counterfeit money in Datang.