Although the Ming frontier was initially vulnerable, in the 300 years they ruled, they [N 001 / built up one of the most closed borders] China has ever known. Not all agreed with the wall-building policy, but it was justified in 1482 when the Ming won a major victory over the [G 12 / Mongols]. Further justification, even though it came much later, was when the wall defending Beijing held off the Mongol raiders in the late 1500s. However, walls even then were not seen as a permanent solution for defence.
Ming rulers during the first half of the 16th century were weak and incompetent. By the middle of the 16th century wall building became the Ming's only policy of dealing with its adversaries. It peaked between 1550 and 1580 and included improvements in Beijing's eastern defences. Proposals for further defence walls were still being made when the [G 11 / Manchus] rode into Beijing and toppled the Ming emperor. Ming policies, like those of earlier dynasties, were apparent from looking at the ruins of their walls: where they were built was where diplomacy with nomads failed, and the more that was built, the greater the hostility.
