Goguryeo-Sui War: Why Did Sui’s Million-Man Army Lose to Goguryeo?

This video explains the strategic reasons why the Sui Dynasty failed in its massive campaign against Goguryeo. After unifying China, Sui attempted to force Goguryeo into submission by mobilizing huge military resources. The campaign was enormous in scale, involving a vast combat force and a large supply structure.

Goguryeo did not rely on open-field confrontation alone. It used strong fortress defense, especially around key positions such as Liaodong Fortress, and applied a scorched-earth strategy to deny food and supplies to the invading army. The documentary emphasizes that Goguryeo’s walls, defensive planning, and ability to endure siege warfare exhausted the Sui army.

Another key factor was logistics. The Sui supply route stretched across a very long distance, and Goguryeo understood that this was the empire’s weak point. Goguryeo forces, together with allied or cooperating groups near the northern routes, threatened the supply chain and pushed the Sui army toward starvation and exhaustion.

The central military climax is the Battle of Salsu. Eulji Mundeok used deception, false surrender, and lure tactics to draw the Sui detachment deep into Goguryeo territory. When the exhausted Sui force retreated, Goguryeo struck decisively at the Salsu River and nearly annihilated the detachment.

The documentary presents the defeat as more than a battlefield loss. Repeated failures against Goguryeo drained Sui power, encouraged internal rebellion, and helped accelerate the collapse of the dynasty. The video frames Goguryeo’s victory as the result of fortress engineering, intelligence gathering, logistics awareness, and the collective will to resist.