During the Ming dynasty, the Liaodong region featured a Great Wall spanning thousands of miles. The section in the Liaohe River bend formed a V-shape, known as the Liaohe River Bend Great Wall. The black line on the map represented the Great Wall, the red star the Zhenjing Fortress, and the blue circle the Liao Swamp.
This particular configuration existed because the Liaohe River bend was then a landscape of endless marshes. This swamp, known as the Liao Swamp, was so muddy and treacherous that it was impassable for both men and horses. Constrained by the terrain, the Great Ming had no choice but to construct defensive walls along the eastern and western banks of the Liaohe River. Before that era, the Liao Swamp had been even more expansive.
To launch an expedition from inside Shanhai Pass into Liaodong, there were only two viable routes. One was the maritime route, sailing from Dengzhou to land in southern Liaodong for combat. The other was the land route south of the Liao Swamp, but this path was blocked by Liaodong City, a fortress notoriously difficult to take. During the Sui dynasty, Emperor Yang launched three campaigns against Goguryeo—not Goryeo—and exhausted the national treasury, yet he only managed to capture cities west of the Liaohe River and never set foot across it. He not only lost hundreds of thousands of troops but also inadvertently supplied Goguryeo with the vast quantities of armor and weaponry they desperately needed, creating immense trouble for his s…
Chapter 958