The Battle that Made China Fear Vietnam |How the Empty Fort Strategy Could Defeat the Strongest Army

By the early 15th century, Đại Việt had been under Ming occupation for two decades. The Ming dynasty, powerful and vast, sought to absorb Đại Việt into its empire, exploiting its resources and erasing its sovereignty. Yet from the mountains and villages, a resistance was growing. Lê Lợi, a wealthy landowner turned rebel leader, emerged as the face of a people’s struggle for freedom. His uprising, known as the Lam Sơn rebellion, began in 1418 with only a handful of followers. Over the years, however, he transformed this scattered resistance into a disciplined army capable of challenging Ming rule.
The key to this transformation lay not only in the courage of the fighters but also in the reforms and strategies Lê Lợi and his advisor Nguyễn Trãi implemented. Lê Lợi understood that conventional battle would favor the Ming, whose armies were larger, better equipped, and more experienced. Instead, the Lam Sơn leadership emphasized mobility, deception, and psychological warfare. Farmers and blacksmiths were recruited, trained, and turned into soldiers. Weapons were crafted locally, with bamboo spears, crossbows, and fire weapons adapted from Chinese designs. The rebels also mastered the terrain, using the dense forests, mountains, and rivers of Đại Việt as natural defenses and ambush sites.
One of the most revolutionary elements of their strategy was the “Empty Fort” or “Ghost City” tactic. Nguyễn Trãi, a brilliant strategist and writer, advocated the use of illusion to manipulate the Ming forces. Rather than defending every village and fort, the Vietnamese would abandon them, leaving the enemy to march through silent lands. The eerie emptiness created an impression of weakness and fear, luring the Ming deeper into unfamiliar territory. In reality, this was a calculated move: the further the Ming marched, the more vulnerable they became to ambushes, supply shortages, and exhaustion.
By 1426, the rebellion had grown into a nationwide movement. The Lam Sơn forces captured key fortresses and began besieging Đông Quan (modern-day Hanoi), the main Ming stronghold. In response, the Ming court dispatched two massive armies in 1427 to rescue their garrison: one under Liễu Thăng marching from Guangxi in the north, and another under Mộc Thạnh advancing from Yunnan in the west. Together, these armies numbered over 100,000 men—by far one of the largest invasion forces the Ming had ever sent to Southeast Asia.
To face this threat, Lê Lợi and Nguyễn Trãi prepared carefully. They understood that defeating these reinforcements would break Ming's resolve and force recognition of Đại Việt’s independence. The plan was bold: avoid confrontation with superior forces, instead stretching the enemy thin, exhausting them, and finally striking in terrain chosen by the Vietnamese. At the heart of this plan was the valley of Chi Lăng—a narrow pass in present-day Lạng Sơn, surrounded by mountains and forests.
The strategy relied on spies and scouts to track every Ming movement, while villages were emptied in advance of the invaders, leaving them with neither food nor shelter.

In September 1427, General Liễu Thăng led an advance force of about 30,000 Ming troops into the Chi Lăng valley. He was confident of a swift victory, believing the Vietnamese resistance had collapsed. The valley, with its tranquil landscape of rivers and lush hills, seemed calm. But the silence was deceptive. Lê Lợi had positioned thousands of troops in hidden encampments along the ridges, while others disguised themselves as peasants or retreated, further reinforcing the illusion of weakness.
As Liễu Thăng’s army moved deeper, the Vietnamese struck. Ambushes erupted from the forests, arrows raining down, cavalry charging from concealed positions. Trapped in the narrow valley, the Ming formations broke apart. Liễu Thăng himself was killed in the chaos, a devastating blow to Ming morale. What had begun as a confident march quickly descended into slaughter. By nightfall, much of the Ming vanguard was annihilated, their banners trampled into the mud.
The disaster at Chi Lăng was only the beginning. With their general dead, the Ming forces retreated in disarray. The Vietnamese relentlessly pursued them, harassing supply lines, cutting off reinforcements, and striking whenever the enemy attempted to regroup. Further west, the second Ming army under Mộc Thạnh also found itself unable to advance. Beset by ambushes and attrition, it too was forced to withdraw.
The climax came at Xương Giang, where the remnants of Ming forces, battered and leaderless, attempted to regroup inside a fortified city.