Hai jinThe Hai jin (海禁) was a ban on maritime activities during the mid-Ming Dynasty of China. Indeed to curb piracy, the ban was ineffective and posed huge hardships on communities of the coast. After extreme pressure from the bureaucracy, the ban was lifted by 1550.
Some have argued that the Hai jin marked a retreat from maritime activities such as the voyages of Zheng He and was a symptom of a period of technological decline and stagnation which culminated in humiliation against Europe in the 19th century. This view was popularized in the Chinese film River Elegy.
Most current historians of China take issue with this view, and point out that the Hai jin was lifted in the mid-Ming and that China was very active in maritime commerce and the global economy after that.