Why was Guangzhou the only Chinese port open to most foreign trade before the First Opium War?

The restriction of foreign trade to Guangzhou (Canton) was not a long-standing historical tradition, but rather a deliberate policy decision by the Qing dynasty. While Guangzhou had long served as a major southern hub for exporting tea, silk, and other goods, it became the sole legal port for Western commerce following a specific imperial decree issued in 1757.1

The Qing emperor enacted this mandate in direct response to British attempts to expand their commercial activities into northern Chinese ports. By centralizing all foreign maritime trade in one location, the Chinese government aimed to tighten control over foreign merchants, enforce strict regulations, and manage the Canton system through a group of authorized merchants known as the cohong. This system allowed the state to monitor foreign personnel, restrict their movement to designated "factories," and impose various fees and legal requirements, effectively insulating the interior of the empire from broader foreign influence until the First Opium War forced the opening of additional treaty ports.1