In 1371, the Hongwu Emperor began restricting private overseas sailing and trade, aiming to tighten state control of coastal security and foreign contact. Legal exchange was increasingly channeled into official, state-managed "tribute trade" rather than private commerce. This policy set the baseline for Ming coastal defense planning for nearly two centuries.
By the early 1380s and 1390s, Ming orders further limited coastal people’s contact and travel abroad, with piracy and security concerns often cited. The policy did not stop all seaborne exchange, but it criminalized much of the private activity that had supported coastal livelihoods. This widened the gap between official rules and coastal economic reality.
To enforce policy and protect the shoreline, the Ming relied on a garrison network known as the weisuo system (guard posts). These units were placed at strategic points and reported through military channels rather than local civil government. Over time, however, the hereditary garrison structure weakened, contributing to defense problems by the mid-1500s.
Beginning in 1405, the Yongle Emperor backed large imperial naval expeditions (often called the Ming treasure voyages) to project power and manage foreign relations through tribute diplomacy. These voyages show that the Ming could switch from restriction to active maritime operations when the court saw strategic benefit. The contrast also highlights how state policy—more than technical capacity—shaped Ming seafaring.
The final major treasure voyage returned in the early 1430s, and the court’s focus increasingly shifted away from large-scale maritime expeditions. Over the longer term, coastal policy tilted back toward control and restriction rather than outward naval presence. This left day-to-day coastal security to garrisons and local administration rather than ocean-going state fleets.
In the mid-1400s, Ming policy included renewed limits on privately building ocean-going vessels and on weapons thought useful to pirates. These kinds of rules aimed to reduce the capacity for unauthorized overseas travel and raiding. They also indicate that the state treated shipbuilding and armed seafaring as security issues, not just economic ones.
In 1523, rival Japanese trade missions clashed violently at Ningbo, a key port in the tribute system. The incident damaged local security and helped interrupt official trade with Japan. It also contributed to a rise in piracy (wokou) pressures along the coast, complicating Ming enforcement of maritime restrictions.
In 1525, during the Jiajing reign, policies further restricted navigation near the coast beyond limited local fishing. This sharper clampdown aimed to curb smuggling and piracy but also squeezed coastal economies. The result was a cycle in which tighter bans could increase incentives for illegal trade and armed maritime activity.
From the 1540s through 1567, widespread raids struck coastal regions including Zhejiang, Fujian, Guangdong, and Jiangnan. Although wokou originally meant Japanese pirates, many raiders in this period were multinational groups and a large share were Chinese, tied to smuggling networks. The crisis pushed the Ming to rethink how to combine coastal defense, anti-piracy operations, and trade policy.
In the early 1560s, general Qi Jiguang became a key commander in coastal defense and built disciplined units trained to fight raiders effectively. He promoted coordinated small-unit tactics (later described in his military manual Jixiao Xinshu), helping improve battlefield performance against well-armed pirate bands. These reforms strengthened the practical side of coastal defense even before national trade policy changed.
After the Jiajing Emperor’s death, the Longqing Emperor’s government approved ending the strict haijin approach in 1567 and restored or strengthened institutions to supervise trade. The change did not mean uncontrolled openness—rules and exclusions remained—but it marked a clear policy pivot from broad prohibition to regulated maritime commerce. The outcome helped stabilize coastal life and provided revenue and administrative tools that pure bans had failed to achieve.
In early 1567, the Ming created Haicheng County centered on Yuegang ("Moon Port") in Fujian and relaxed enforcement so private overseas trade could be conducted there under oversight. Officials argued that regulated trade could be taxed and could reduce incentives for smuggling and piracy. Yuegang became the key legal outlet for private maritime commerce as the policy shifted toward managed opening.
Ming coastal defenses and the Haijin maritime prohibition (1371–1567)