Frontier Defense of Vietnam's Ly Dynasty

Timeline

1. 1121–1126Song–Viet border · ChinaThe Ly dynasty kept peace with Northern Song in the name of tribute while setting up passes and forts on the northern border to guard against Song military pressure and tribal incursions, forming a frontier pattern of 'nominal subordination, actual autonomy'.
2. 1123–1129Northwestern mountains · VietnamThe court dispatched generals to pacify tribes such as the Nong and Lao, maintaining their allegiance through investiture, seals and annual grants, and campaigning against rebellious tribes, consolidating Ly dynasty practical control over mountain areas beyond the Red River basin.
3. 1125–1130Red River Delta · VietnamThe Ly dynasty implemented military-agricultural colonies on the frontier, using farming to support troops and grain to fund garrison rotation, and reformed local military administration so that the defense system and central tax-corvée system supported each other, strengthening logistical capacity for southern expansion.