Ming Great Wall Border Defense System

Timeline

1. c. 1470–1570Xuanfu–Datong frontier garrisons · Xuan-DaThe Ming established military garrisons at nine frontier sites including Xuanfu, Datong, and Jizhou, building brick-and-stone-faced walls, watchtowers, and beacon towers to form a defense-in-depth and early-warning communications network; garrison troops farmed military colonies for self-sufficiency, constituting an independent border defense economy.
2. 1580–1590Along the Ji-Liao Great Wall · Ji-LiaoIn the 1580s the Ming court maintained the Nine Frontier Garrisons' defenses after Altan Khan's investiture and tribute, continuing to build watchtowers and passes at Jizhou and Liaodong; meanwhile Jurchen tribes grew in power, and the Liaodong wall and beacon tower system became the frontline barrier against the emerging northeastern threat.
3. c. 1585–1610Liaodong Great Wall · LiaodongThe Ming Great Wall was not merely a static wall but also an administrative boundary for garrisons, postal relay stations, trade markets, and tributary trade; however, arrears in troop pay, factional strife, and the rise of the Later Jin meant that the Liaodong defense line, still relatively stable in the 1580s, faced systemic collapse by the early 17th century.