How heavy iron coin strings in Sichuan helped drive the development of government-backed paper money.
In Song-era Sichuan, iron cash coins were widely used, and their weight made large payments inconvenient. That practical pressure helped merchants develop receipts and credit instruments that could stand in for coins during settlement.
Iron was heavy and cheap. Large purchases could require thousands of coins, creating a transport problem for merchants who had to move cash between markets.
The Invention of Jiaozi (1024 CE)
Early jiaozi developed from deposit receipts and merchant credit in Chengdu. Later government issues formalised the system.
Instead of retrieving heavy coins for every payment, traders could use receipts and credit instruments to settle debts. Jiaozi is an important early example of paper money and a useful case study in how payment instruments can grow from commercial practice.
State Takeover & Anti-Counterfeiting Mints
The Northern Song government later took a larger role in issuing paper money, including official issues associated with Chengdu. Surviving notes used printing, seals, and warnings as anti-counterfeiting measures, but the exact materials and colour process varied by issue:
- Notes were printed on paper and marked with official designs and seals.
- Woodblock printing made detailed text and images possible.
- Warnings and penalties for counterfeiting were part of the wider paper-money system.
When Venetian traveler Marco Polo visited China two centuries later under Kublai Khan, he was stunned to discover that the Emperor made money out of tree bark, calling it the ultimate alchemy. The Jiaozi marked the moment coins evolved from heavy metallic matter into light credit certificates.
Test Your Knowledge
Sources & References
- American Numismatic Association Money Museum: An Experiment in Paper Virtual Money — Sichuan promissory notes, heavy coins, Jiaozi, and the government's takeover.
- National Museum of China: Huizi edition — the Northern Song Sichuan iron-money region and early Jiaozi paper money.
- Chinese Text Project: Shu Zhong Guang Ji, chapter 67 — historical account of private Jiaozi and the establishment of the Yizhou Jiaozi Office.