Monopoly Bureau
Originally the government of the Tang dynasty was less than receptive to the idea of bills of exchange and had attempted banning them on multiple occasions, but in 812 flying cash were officially accepted as a valid means of exchange. After the government had accepted these bills the supervision of flying cash was handled by the Ministry of Revenue (戶部), the Tax Bureau (度支司), and the Salt Monopoly Bureau (鹽錢司). The state began printing their own notes. Flying cash would remain in use until the early period of the Song dynasty.