Facts from "1493" by Charles Mann as cities from the book and the sources he cites.
Why China Stopped Sailing?
*One part cities several commentators who say that it was the cause of a lack of Curiosity or drive due to the Confucian Ideaology and political infighting of bureacratic factions in which a faction that opposed the ship building.
*Other scholars disagree on the above and any insinuation the Chinese lacked curiosity and drive. The fact was that the Ming were the superpower of the age and despite the fact that the Chinese could have easily sailed to Europe they found no power that could threaten their hegemony or rivaled their civilization so their was no need to continue expeditions FROM THE GOVERNMENT.
*After Fifty Years though the Sea Ban inplaced was abandoned by the Ming government as ineffective and idiotic.
The Sea Ban's Effects
*While the Sea ban focused on wringing out their own merchants, the ban certainly did not stop ships from entering Chinese harbors-at least those that were 'Tribute Payments', at least 38 nations sent delegations to pay homage to the Emperor.
*The Yuan Dynasty had tried simillar Sea Bans in 1303, 1311, and 1320 but they found it more profitable and less of a hassle to tax private trade rather then control it.
*Soon after the ban the Ming government nigh completely dissolved its coastal police forces. The result was of course smugglers and pirates grew exponentially.
*The majority of these 'Woku' were not Japanese but Chinese traders and smugglers who turned to smuggling after the ban outlawed their livelyhood. "Fired government clerks, starving farmers, disgraced monks, escaped convicts, and sailors."
*The main center of this piracy and the area most perfectly suited and worst hit by it was the Fujian province which has infamously poor and rocky land but, great natural harbors in equal abundance.
*Yuegang was the epicenter of the area's maritime history, starting in 1547 when "a Dutch Merchant/pirate/smuggler group set up a base on Wu Island". The Dutch group in question while flying the Dutch flag was made up of a crazy quilt of Spanish, Portugese, Dutch, and Malays who traded happily witht he surrounding Woku fleets. The Fujian Emperor would later attack the 'Dutch' on the island and fail, only forcing the 'Dutch' to flee (and pirate on Chinese and Japanese ships) after he beheaded about 90 of the local merchants who had traded with the group.
*For his further Anti-Piracy actions in Yuegang the city's wealthy, merchant elite complained to the Emperor who had the Governor demoted. Said Governor would commit suicide a few years later.
*The Twenty Four Generals, among other groups, were fleets of merchants from Yuegang who pooled their resources and worked with the Woku and carved up Yuegang into a series of factions. When Imperial soldiers tried to disband them and other groups the Imperials were defeated which caused a new surge of factions.
*Just prior to the ban on Sea Trade, the last major attempt by the government to reign in the region was made by Vice Commissioner of Coastal Survalience, Shao Pian...whose coastal forces were outnumbered and outgunned by the local Woku and was driven from the region "we lost one outpost, two smaller outposts, a prefecture, six counties, and no fewer then twenty-size fortified towns..." a Beijing gazetteer is said to have reported.
Why did the Ming really end the Sea Ban?
*They NEEDED Silver. Apparently, China did not have all the resources it could need. Its Silver and Copper mines had been long since tapped out and the Paper Bill inflation and collapse of the Song, Yuan, and Ming Dynasties had taught the Ming Emperors that paper money was absolutely worthless. So they turned to Silver coinage by the 1570's.
*Fairly soon the vast majority of the Chinese economy was running on a supply of Silver splinters that given the size of the Chinese economy and the desire of the Ming government to spent was no where near enough.
The Result?
Manila in the Philippines by 1591, only twenty years after Chinese merchants had first entered the city for trade with the Spanish, was a small European 'Forbidden City' of a few hundred Europeans which was surrounded by a even larger city, Parain, of several thousand Chinese immigrants who were allowed to worship their 'idols' and traded free of Ming scrutiny. The "Ghetto" of Parain was so successful that even the Spanish colonists preferred shopping in there rather then Manila because the trades of the Chinese were so good and cheap.