Empress Lü Zhi
During the early Western Han period, founding Emperor Gaozu of Han (r. 202–195 BC) closed government mints in favor of coin currency produced by the private sector. Gaozu's widow Empress Lü Zhi, as grand empress dowager, abolished private minting in 186 BC. She first issued a government-minted bronze coin weighing , but issued another, weighing , in 182 BC. The change to the lighter coin caused widespread inflation, so in 175 BC Emperor Wen of Han (r. 180–157 BC) lifted the ban on private minting; private mints were required to mint coins weighing exactly . Private minting was again abolished in 144 BC during the end of Emperor Jing of Han's (r. 157–141 BC) reign. Despite this, the bronze coin was issued by both central and local commandery governments until 120 BC, when for one year it was replaced with a coin weighing . Other currencies were introduced around this time. Token money notes made of embroidered white deerskin, with a face value of 400,000 coins, were used to collect government revenues. Emperor Wu also introduced three tin-silver alloy coins worth 3,000, 500, and 300 bronze coins, respectively; all of these weighed less than .