Background
Ever since the Battle of Xiaoyaojin in the twentieth year of Jian'an (215), Hefei had been the linchpin of Caowei's Huainan defensive line. Almost every Eastern Wu northern campaign passed through Hefei. The problem was structural: the old Hefei city sat close to the lakes and rivers to the south, far from Shouchun to the north, allowing Wu naval forces to approach and lay siege with ease, while Caowei's infantry and cavalry relief had to march long distances. Man Chong, drawing on years of defensive experience, identified this structural weakness — Hefei's geographic position placed it at a natural disadvantage in every engagement [c:17248]. By the first year of the Qinglong reign (233), Sun Quan had proclaimed himself emperor and pressure along the Wu-Wei frontier increased sharply. Man Chong concluded that the entire defensive line needed to be fundamentally restructured, and submitted a memorial proposing the construction of a new city thirty li west of Hefei at a commanding highland position that could serve as a natural strongpoint.
Key Figures
Man Chong, as the senior frontline commander, was the originator of this proposal. His logic: draw Wu forces out of the water-warfare environment where they excelled, compelling them either to fight a decisive land battle deep inland or to hesitate for long stretches at the water-land transition, thereby breaking the cycle of Hefei being besieged repeatedly. General of the Household Jiang Ji raised strong opposition in court, on grounds of political optics: relocating the city was "showing weakness to the world" — yielding ground before the enemy had even attacked, which would embolden the foe, damage morale, and lead to passivity across the entire Huaibei front [c:17248]. This was the classic "prestige-school" position: the symbolic political significance of a city outweighs its tactical value. Secretariat Director Zhao Zi sided with Man Chong, arguing that the art of war is inherently a form of deception: "appearing capable while showing weakness, dangling advantage to lure the enemy" — this is orthodox military teaching. Emperor Ming Cao Rui ultimately adopted the proposal of Man Chong and Zhao Zi.
Central Issue
The substance of this debate was a contest between the political value and the tactical value of fortifications. What Jiang Ji saw was the political signal: "abandoning the old city equates to admitting the enemy is strong and we are weak." What Man Chong saw was the tactical trap: "the old city sits by the water — the enemy can besiege it at any moment." In his second memorial Man Chong cited Sun Tzu's principle of "appearing weak when one is capable," inverting the "showing weakness" that Jiang Ji feared into a deliberate tactic of luring the enemy in. This is a rare instance of a frontline commander winning a court debate — ordinarily, central bureaucrats far from the front override tactical reason with political posturing. Cao Rui's final ruling in support of Man Chong reflects his respect for frontline judgment, and also reflects Caowei's strategic orientation in the Huainan direction shifting from "forward deterrence" to "waiting at ease for the exhausted enemy."
Political Consequences
The first validation of the new city came quickly. That same year Sun Quan personally led a large army intending to besiege the new city, but found it lay far from the water — his fleet could not reach directly below the walls — and "for twenty days dared not disembark" [c:17248]. Those twenty days of hesitation were a key strategic dividend: cut off from their waterborne lines of communication, Wu troops began to waver in morale and logistics. Man Chong seized the opportunity, pre-positioning six thousand infantry and cavalry in ambush, and when Sun Quan finally decided to go ashore and stage a "display of force," Man Chong's troops struck: several hundred heads were taken. From that point on, every Wu northern campaign against Hefei faced the same dilemma: either abandon the naval advantage and go deep inland, or look up at the city walls and sigh helplessly. In the long term, Hefeixincheng became the anchor of Caowei's Huainan defensive line, not again becoming the focus of Eastern Wu or rebel contention until Zhuge Ke's campaign at the Battle of Dongxing (252) and the revolt of Wuqiujianwenqinzhiluan (255). Man Chong became one of the most relied-upon regional senior officials of Caowei's later period.
Counterfactual Analysis
What if Jiang Ji's objections had prevailed and the old city had been left in place? The consequences would likely have been twofold. First, Sun Quan's large-scale northern campaign the following year (first year of Qinglong) could very plausibly have achieved a local breakthrough at the old city — at minimum establishing a siege posture before any siege equipment was burned. Second, the political pressure of Cao Rui's personal campaign would also have been diminished, since the old city was by nature "capable of being besieged," while the new city's resistance to prolonged assault was precisely what made the Wei emperor's personal expedition a credible deterrent. Another counterfactual: what if the new city had been built even farther away, deeper into the interior, so that Wu forces simply chose not to attack it and instead bypassed it to raid around Shouchun? The outcome might have been worse — the forward position would have lost its function as "bait." Man Chong's choice of "thirty li to the west" rather than farther was exactly the precise balance between "value as a lure" and "geographic strength." This is why later generations said Man Chong "knew Hefei like the lines of his own palm" — his understanding of this area's terrain and Wu's patterns of behavior was the product of nearly twenty years of battlefield experience accumulated since Xiaoyaojin.