Haijin

The Haijin (海禁) or sea ban was a series of related isolationist policies in China restricting private maritime trading and coastal settlement during most of the Ming dynasty and early Qing dynasty. The policy introduced by the Ming founder Zhu Yuanzhang significantly hampered the growth of China's domestic trade,^[1] although the Ming was not able to enforce the policy in full despite official proclamations, and trade continued in forms like smuggling until the late Ming government opened the port of Yuegang for trade. Later, the early Qing dynasty's anti-insurgent "Great Clearance" (1661–1683) also caused considerable devastating effects on communities along the coast, until the Qing seized control of Taiwan and opened coastal ports to foreign trade.

First imposed to deal with Japanese piracy amid the mopping up of Yuan dynasty partisans, the sea ban was completely counterproductive: by the 16th century, piracy and smuggling were endemic and mostly consisted of Chinese who had been dispossessed by the policy. China's foreign trade was limited to irregular and expensive tribute missions, and the military pressure from the Mongols after the disastrous Battle of Tumu led to the scrapping of Zheng He's fleets. Piracy dropped to negligible levels only upon the end of the policy in 1567, but a modified form was subsequently adopted by the Qing. This produced the Canton System of the Thirteen Factories, but also the opium smuggling that led to the First and Second Opium Wars in the 19th century.

The Chinese policy was mimicked in other East Asian countries in the same period, such as in Edo period Japan by the Tokugawa shogunate, where the policy was known as kaikin (海禁) / Sakoku (鎖国), as well as in Joseon Korea, which became known as the "Hermit Kingdom", before they were opened militarily in 1853 and 1876 respectively.