In July 1859, the third article of the Treaty of Amity and Commerce negotiated by Townsend Harris (1804–1878) in 1858, opened the ports of Nagasaki, Kanagawa, and Hakodate to foreign trade, creating the first treaty ports in Japan. Unlike Hong Kong, for example, these treaties were eternal—there was no expiration date to any of the terms. This fact was to mold Japanese domestic and foreign policy through the Meiji Period (1868–1912).
As the name might suggest, a treaty port was established by treaty. They were a leasehold, a sort of limited colonialism in which the area around a strategically located harbor area was designated as a place where extraterritoriality prevailed. So, in addition to establishment by treaty, extraterritoriality was a defining factor of a treaty port. In Japan, foreigners were limited to within thirty miles of the treaty ports, unless they were contracted by the government. Any expedition outside of this boundary required special permission and a passport. This system lasted in Japan until 1899, when the renegotiated settlement from 1894 went into effect.
The origins of extraterritoriality (later sometimes shortened to extrality) were in principle set forth in Emmerich de Vattel’s The Law of Nations or Principles of the Laws of Nations Applied to Nations and Sovereigns (1758). This seminal work by a Swiss diplomat established guidelines for the actions of independent nations in times of peace and war. It was read by important figures in American history like George Washington and Benjamin Franklin and was thus influential in the formation of the policies and laws of today. In this book, the word extraterritoriality was used but was closer to what we now call diplomatic immunity. It was not until Western imperialism against isolationist Asian nations that the present meaning evolved.[i] It refers to the concession that allowed (concessions being another word that was sometimes used to refer to the treaty ports) each treaty nation to judge its own citizens according to the laws of the home country.
When China was forced to cede ports to the British in 1842 as a result of the Opium War, one of the conditions set in the Treaty of Nanjing (Nanking) was extraterritoriality. The British government demanded this right because they saw the Chinese justice system as brutal and unjust. As imperious as it seems in retrospect, it was meant as a measure to protect British citizens. The Chinese treaty ports—Canton (Guangzhou), Shanghai, and Hong Kong were the biggest ones—were the prototype for concessions later obtained in other Chinese and East Asian ports. Thus, when Townsend Harris negotiated a commercial treaty, the fourth clause in the convention was: “Americans to be exclusively under control of their consuls, and to be tried by American Law.”[ii] As other countries concluded treaties, they made sure to obtain all the rights granted to the Americans.