How a Secret Dam and a Feigned Retreat Decided the Fate of Ancient China
In 204 BC, General Han Xin faced a massive coalition of Chu and Qi forces across the Wei River. Instead of a direct assault, he used a hidden dam to manipulate the water levels, orchestrating a brilliant tactical trap that shattered his enemies and secured the richest kingdom in the north.
The Battle of Wei River in November 204 BC was a pivotal moment in the struggle between Liu Bang and Xiang Yu. By this time, the two former sworn brothers were locked in a grueling stalemate in the Central Plain. Han Xin, tasked with conquering the northern kingdom of Qi, recognized that Qi’s wealth and manpower were essential to breaking this deadlock. While a diplomat named Li Yiji had already secured a tentative peace with King Tian Guang, Han Xin’s advisor Kuai Che convinced him that the conquest was his to claim by force, leading to a surprise invasion.
The conflict reached its climax when the Chu general Long Ju arrived to bolster the Qi forces. Positioned on the south bank of the Wei River, Long Ju ignored advice to fight a war of attrition. Instead, he sought a decisive battle. Han Xin, anticipating this, secretly constructed a makeshift dam with sandbags upstream to lower the river's depth. He initiated the engagement by attacking and then performing a feigned retreat, luring Long Ju’s vanguard across the shallow water. Once the enemy was partially across, Han Xin released the dam, cutting off the vanguard and isolating Long Ju, who was killed in the ensuing chaos.
The victory was total. With their leader dead, the Chu army disintegrated, and the Qi forces scattered. Han Xin continued his campaign into 203 BC, systematically dismantling the remaining resistance of the Tian clan. The conquest of Qi left Xiang Yu in a precarious position, effectively stripping him of his northern options. Although Xiang Yu attempted to bribe Han Xin into neutrality with a proposal to divide China, Han Xin remained loyal to Liu Bang, citing his past experiences serving under the dismissive Xiang Yu. This loyalty paved the way for the final Han victory at the Battle of Gaixia.
Source: Battle of Wei River
