Why were Fuzhou and Xiamen opened as treaty ports in the 19th century?

Fuzhou and Xiamen were opened as treaty ports in the 19th century as a direct consequence of China's defeat by Britain in the first Opium War (1839–1842).12

Following the conflict, the Treaty of Nanjing, signed in 1842, mandated that China increase the number of ports open to foreign trade and residence from one (Canton) to five. Fuzhou and Xiamen were among the four additional ports designated under these terms.134

The establishment of these treaty ports was part of a broader effort by Western powers to gain commercial privileges, legal concessions, and territorial access within China. For Fuzhou and Xiamen, this status facilitated their roles as major centers for the tea trade, with Fuzhou becoming particularly significant due to its proximity to tea-producing districts. These ports also served as gateways for Western influence, including the introduction of foreign municipal institutions and, in the case of Fuzhou, early experiments with Western technology such as the Fuzhou Navy Yard.1342