Why did the Ming government devote major resources to the Great Wall?

The Ming dynasty (1368–1644) invested significant resources into the Great Wall of China primarily to ensure national security and prevent the Mongols from threatening China again.1

Following the expulsion of the Mongols, Ming emperors maintained a defensive posture in the north to prevent any reconsolidation of Mongol power. This concern was so central to Ming foreign policy that the Yongle emperor moved the national capital from Nanjing to Beijing in 1421 to be closer to the frontier.1

To protect the capital and the northern border, the Ming government:
* Strengthened and expanded the wall to its present-day extent, utilizing strategic passes such as Juyong, Daoma, and Zijing.21
* Established nine defense commands stretching from Manchuria to Gansu, which were heavily garrisoned to repel incursions.21
* Maintained the wall as a critical barrier against raiding forays by groups such as the Oirat and Tatars.1

These efforts reflected the Ming commitment to keeping the frontier secure and preventing the resurgence of hostile forces on their northern border.1