The Currency System of the Lianghuai Region during the Southern Song Dynasty: Focusing on Jiaozi and Iron Coins

During the Southern Song period, the Lianghuai region emerged as a militarily and fiscally critical frontier zone bordering the Jin dynasty. In response, the central government implemented a distinct monetary policy tailored to the region’s geopolitical demands. The Huainan jiaozi (淮交), a region-specific paper currency, was introduced to replace copper coins and alleviate the transactional inefficiencies caused by iron coins. Initially, the jiaozi was issued under a credit system backed by iron coins, following the classical principle of “operating the virtual with the real” (以實運虛). However, as the state increasingly overissued paper currency and iron coins, while also introducing hybrid circulation with hui-zi (會子), the monetary structure destabilized. The original framework in which the jiaozi functioned as the standard and iron coins acted as the referent was reversed—iron coins came to determine the value of the jiaozi, a transformation conceptualized as the shift from “jiaozi valuing iron coins” to “jiaozi being valued by iron coins” (被稱提). This study examines the structural reversal of value representation in Huainan jiaozi circulation, highlighting the Song dynasty's regional monetary diversity, the fragility of its fiduciary currency system, and the broader institutional constraints of its monetary policy. Ultimately, the decline of the Huainan jiaozi provides a critical case for understanding the tension between policy-driven monetary expansion and the market's trust-based acceptance of currency.