At a time when trade in the west was still conducted by bartering, the business-savvy people of Song-dynasty China were already accustomed to using money. There was even a form of paper currency circulating in Sichuan, where it was known as a "handover."
當西方還在以物易物的買賣交易時，宋人已經普遍用錢來交易，在四川地方甚至已經開始使用叫做「交子」的紙幣，可見宋人真是頭腦一流的商業民族。