- Chinese: 海禁 (hai jin)
Chinese overseas activity, including trade, was not cut off entirely, but was merely limited in certain ways; in particular, trade outside of that associated with tribute missions was strongly proscribed. This meant that members of the large overseas Chinese communities in Southeast Asia and elsewhere could only return home to visit, legally, as members of tribute missions; many were able to do so, leveraging their knowledge and skill in maritime navigation, commerce, Ming bureaucracy, ritual, Chinese language, and/or other relevant matters, to gain positions in tributary missions. Still, unofficial, or private, trade, continued in great volume - it was just now considered illegal smuggling.
The volume of Chinese goods flowing out of China decreased dramatically, increasing the market for goods such as Southeast Asian ceramics and silks. The number of active Chinese merchants on the seas and in the ports similarly decreased, creating greater opportunities for Southeast Asian, Japanese, and especially Ryukyuan merchants to expand their activity and revenues. The official tally trade between Ming China and Ashikaga Japan was ended after 1523, and in 1557, Chinese were banned from traveling to Japan, and Japanese were banned from making port in China. These bans allowed for the development of Nihonmachi (Japantowns) in Southeast Asia, and the expansion of Japanese maritime activity in the 16th century, while also providing for the increased prominence of the Kingdom of Ryûkyû as an intermediary or entrepot for Chinese, Japanese, and Southeast Asian goods being provided to Southeast Asian, Japanese, and Chinese markets.
The removal of these maritime prohibitions in 1567 played a significant role in the decline of Ryukyuan maritime activity and commercial trade.
Though piracy (see wakô) is generally cited as the key impetus for the implementation of this policy, Angela Schottenhammer argues that it was instead a new political philosophy initiated by the Hongwu Emperor, and a shift from overseas trade to domestic trade via the Grand Canal which served as the main causes for this shift in policy.
- Schottenhammer, Angela. "The East Asian maritime world, 1400-1800: Its fabrics of power and dynamics of exchanges - China and her neighbors." in Schottenhammer (ed.) The East Asian maritime world, 1400-1800: Its fabrics of power and dynamics of exchanges. Harrassowitz Verlag, 2007. pp1-83.
- Chan, Ying Kit. “A Bridge between Myriad Lands: The Ryukyu Kingdom and Ming China (1372-1526).” Thesis, National University of Singapore, 2010, 59. http://scholarbank.nus.edu.sg/handle/10635/20602.