Strategic Background
When Sun Quan died in 252 CE, Zhuge Ke assumed supreme control of Sunwu's military and political affairs in his capacity as Grand Tutor and regent. His greatest political challenge was "how to establish his paramount authority within a still-unsettled regency arrangement." That same winter, his brilliant victory at Dongxing — routing a three-pronged Wei invasion — was the most magnificent triumph of his regency, but it also led him to misjudge the situation. He believed that pressing northward off this success could single-handedly alter the tripartite balance of the San Guo and elevate Sunwu to the strategic apex of "unifying the northern bank of the Yangtze River." Yet Caowei was at that moment in a transitional period in which Sima Shi had monopolized the court and the internal reverberations of Gaopinglingzhibian had not yet been fully absorbed — outwardly stable but internally under considerable tension. Zhuge Ke's assessment was that launching a northern campaign during Wei's power vacuum could replicate his uncle Zhuge Liang's strategy of "offense as defense." The problem was that he had not fully evaluated Sunwu's own capacity to absorb the costs of war, and he underestimated the defensive depth that Man Chong's era had built into Hefeixincheng.
Deployment of Forces
The Wu army claimed two hundred thousand men; the actual figure was probably between one hundred and one hundred and fifty thousand, making it the largest northern offensive in Sunwu's history. Zhuge Ke commanded in person; Zhu Yi, Teng Yin, Ding Feng, Cai Lin, and others led separate columns. The operational objectives were set in three ascending stages: "first take New Hefei, then aim for Shouchun, and finally threaten the northern Huai River region." On Wei's side, the garrison commander Zhang Te had only three thousand troops, but the fortifications had been designed by Man Chong — amply stocked with grain, equipped with internal wells, and difficult for siege equipment to approach — making it the most thoroughly fortified node in the Huai River defensive line. Caowei's central response was orchestrated by Sima Shi: on one hand he dispatched Guan Qiujian and Wen Qin with the main force to relieve the siege; on the other, he exploited the objective conditions of the Huai–Huai summer heat and humidity to let the Wu army wear itself out.
Critical Decision Points
The outcome of this campaign was determined primarily by three errors in Zhuge Ke's judgment. The first was his choice of "surround the city and repel relief forces" rather than "divide his troops to intercept relief forces" — a formation used effectively before by Zhang Liao and Sima Yi, but for Wu's amphibious expeditionary force, which lacked the mobility to penetrate deep inland, the cost of a siege was drastically underestimated. The second was his excessive credulity toward Zhang Te's feigned surrender. Zhang Te used the pretext of "the law of Wei allowing surrender after a hundred-day siege without relief, without punishment of one's clan" to beg for a delay; this ploy had obvious weaknesses, yet Zhuge Ke, eager for victory and reluctant to sacrifice men, missed the critical window for a decisive assault. By the time Zhang Te spent the night repairing the city wall, the window of initiative had been irrevocably lost. The third was his heavy-handed suppression of dissent within his own ranks: Zhu Yi was stripped of command for disagreeing with the siege plan, and mid- and lower-level commanders including Cai Lin became so resentful that some defected to the enemy on the battlefield — this "internal purge" behavior caused morale to unravel even further, and once an epidemic struck, the army collapsed rapidly.
Outcome and Echoes
This engagement was a devastating blow for Wu forces. The San Guozhi records that those incapacitated numbered in the tens of thousands and those killed exceeded half; those captured were beyond counting. During the withdrawal, "ailing and disabled soldiers filled the ravines," and over the course of several days Wei general Wen Qin pursued and cut down tens of thousands more of the scattered troops. This campaign was the largest-scale and most catastrophic defeat in all of Sunwu's external military history. The direct result was the complete collapse of Zhuge Ke's prestige at court. On returning to the capital, rather than accepting punishment, he tried to reassert authority through severity and purge political rivals — this rigidity became his death warrant. In the tenth month of the same year, Sun Jun used a banquet as cover to have him killed, and his descendants were wiped out in the aftermath. The political influence of the Zhuge clan within Sunwu thus came to an end. The deeper historical reverberations were that Sunwu thereafter entered a cycle of internal strife in which the imperial clan and powerful ministers alternated in seizing power — Sun Jun and Sun Liang held court successively, and by the time Sun Xiu died in 264 and Sun Hao succeeded, there was no longer any domestic political cohesion capable of matching Jin's strength. The destruction of Sunwu in 280 CE was practically a foregone conclusion.
Counterfactual Analysis
Suppose Zhuge Ke had withdrawn from New Hefei in a timely fashion, accepted the strategic error, and stabilized the domestic situation — his position at court would have suffered damage but need not have been fatal, and Sunwu might have maintained equilibrium on other fronts for some time. Had he not purged Zhu Yi and preserved the cohesion of his officer corps, the cohesion of the Wu army's interior would have been retained and the scale of the defeat would at least not have compounded into losses of more than half in the retreat. Conversely, had Zhuge Ke chosen after the great victory at Dongxing to consolidate those gains rather than immediately launching a northern offensive, directing his military strength toward digesting the advantages already won along the Huai River and strengthening garrison farming in the Huai region, his regency prestige could have been sustained for many years, and Sunwu's timeline of decline might have been delayed by five to ten years. The deepest lesson of this campaign is: a regent must above all never "use foreign war as a domestic mandate." Once military victory becomes the sole source of political authority, defeat is no longer merely a military loss — it instantly transforms into the collapse of the foundations of power. Zhuge Ke used three thousand defenders and a summer epidemic to write the heaviest footnote in the political science of regency in the later San Guo period.