The Canton System served as a means for Qing China to control trade with the West within its own country by focusing all trade on the southern port of Canton (now Guangzhou). The protectionist policy arose in 1757 as a response to a perceived political and commercial threat from abroad on the part of successive Chinese emperors.

From the late seventeenth century onwards, Chinese merchants, known as Hongs, managed all trade in the port. Operating from the Thirteen Factories located on the banks of the Pearl River outside Canton, in 1760, by order of the Qing Qianlong Emperor, they became officially sanctioned as a monopoly known as the Cohong. Thereafter Chinese merchants dealing with foreign trade acted through the Cohong under the supervision of the Guangdong Customs Supervisor, informally known as the "Hoppo", and the Governor-general of Guangzhou and Guangxi.