Which treaty signed in 1842 opened five Chinese ports to British trade?

The Treaty of Nanking opened five Chinese ports to British trade in 1842. Signed on 29 August 1842, it ended the First Opium War between Qing China and Great Britain.

The treaty opened Canton, Amoy, Foochow, Ningpo and Shanghai—today generally called Guangzhou, Xiamen, Fuzhou and Ningbo, alongside Shanghai. It dismantled the Canton System, which had restricted most Western maritime trade to Canton and channelled foreign merchants through licensed Chinese intermediaries.

The agreement also required China to pay a substantial indemnity and ceded Hong Kong Island to Britain. Its terms were imposed after Qing military defeat and became a foundational example of what Chinese historians later called the “unequal treaties.” The treaty was negotiated by the British representative Henry Pottinger and Qing officials including Qiying.

A frequent mix-up is the Treaty of Tientsin, signed in 1858 after the Second Opium War; it opened additional ports and expanded foreign privileges. The Treaty of Nanking is also called the Treaty of Nanjing—the difference is an older and newer romanisation of the same city’s name.