Ming Great Wall

Timeline

1. 1420–1487Xuanfu–Datong · North ChinaAfter the Yongle reign moved the capital to Beijing, the principle of 'the Son of Heaven guards the gate of the realm' was reinforced, with brick-and-stone walls, passes, and beacon fires built at the Nine Frontiers including Xuanfu, Datong, and Liaodong; the Chenghua reign added hollow watchtowers and standardized beacon tower spacing, forming an integrated wall-pass-tower-beacon defense chain that laid the foundation for mid- and late-Ming frontier defense.
2. 1521–1530Datong Garrison · DatongAfter the Jiajing Emperor acceded in 1521, Mongol raids had grown more frequent since the Zhengde reign; the Ming court added wall sections and beacon towers at Datong and Xuanfu and strengthened rotating guards garrisons. Great Wall works of the 1520s focused on consolidating existing defenses and improving early warning and firepower support, accumulating pressure toward the frontier crisis preceding the Gengxu Incident of 1550.
3. 1525–1530Juyong Pass · Ji GarrisonIn the later 1520s the Ming court emphasized the direct shielding role of the Ji Garrison–Juyong Pass line for Beijing, repairing pass fortresses, dispatching additional frontier troops, and perfecting the beacon signal system; here the Ming Great Wall controlled passages through dangerous passes, working with the Nine Frontiers general and governor systems to form the capital's last line of defense.