Jiaozi, as the earliest popular paper ratio in China, was put into practice in the early years of Northern Song Dynasty, and was standardized by Zhang Yong in Jingdezhen, which promoted the further development of Jiaozi. Jiaozi itself is derived from the convenience of merchants' transactions, so where did so many merchants come from in Sichuan, which has always been regarded as a barren land?
The reason why there were so many rich people in Sichuan in the Song Dynasty can be traced back to the Anshi Rebellion. After the Anshi Rebellion broke out, Emperor Xuanzong of the Tang Dynasty took people to take refuge in Shu, and many rich people in Chang 'an also fled to Sichuan. The arrival of these rich people promoted the economic development of Sichuan at that time, and Sichuan, a barren place, also had more foreign trade exchanges. However, Shu Dao is difficult, as you can know from Shu Dao Nan. It is unrealistic for businessmen to carry a lot of copper coins with them when they want to conduct foreign transactions. Moreover, bandits are rampant in Sichuan, and it is not safe to carry a lot of money. Therefore, in order to facilitate the trade and the safety of businessmen, Zhang Yong began cross fertilization in Sichuan during the Jingdezhen period.
Historically, there were few iron mines in Sichuan, with low mining capacity and inadequate smelting technology. For these reasons, there are few subway coins. On the contrary, after Sichuan's paper-making reform, due to geographical reasons, bamboo was abundant, and Sichuan's paper-making technology reached its peak at that time. It was a trend of economic development at that time that paper money replaced iron coins, and the popularity of jiaozi in Sichuan was also a historical necessity.