Jiaozi () was a form of promissory note which appeared around the 11th century in the Sichuan capital of Chengdu, China. Numismatists regard it as the first paper money in history, a development of the Chinese Song Dynasty (960–1279 CE). Early Jiaozi notes did not have standard denominations but were denominated according to the needs of the purchaser and ranged from 500 wén to 5 guàn. The government office that issued these notes or the Jiaozi wu () demanded a payment or exchange fee () of 30 wén per guàn exchanged from coins to banknote. The Jiaozi were usually issued biannually. In the region of Liang-Huai () these banknotes were referred to as Huaijiao (淮交) and were introduced in 1136 but their circulation stopped quickly after their introduction. Generally the lower the denominations of the Jiaozi the more popular they became, and as the government was initially unable to properly regulate their production, their existence eventually led to undesirably high rates of inflation. To combat counterfeiting, jiaozi were stamped with multiple banknote seals. The Jiaozi was first used in present-day Sichuan by a private merchant enterprise. They were issued to replace the heavy coins (鐵錢) that circulated at the time. These early Jiaozi were issued in high denominations such as 1000 qiàn, which was equal to one thousand coins that of security. As denominations were not standard their nominal value was annually added by the issuing company. During the first 5 years of circulation there were no standard designs or limitations for the Jiaozi but after 5 years the sixteen largest Sichuanese merchant companies founded the Paper Note Bank (Jiaozi hu 交子戶, or Jiaozi bu 交子鋪) which standardised banknotes for them to eventually become a recognised form of currency by the local government with a standard exchange fee of 30 wén per string of cash in paper currency. As bankruptcy plagued several merchant companies the government nationalised and managed the production of paper money and founded the Jiaozi wu (交子務) in 1023.