Background
Sunwu had begun systematically administering the Lingnan region from the Chiwu period of Sun Quan's reign onward, but Jiaozhou (comprising the commanderies of Jiaozhi, Jiuzhen, and Rinan) was thousands of li from Jianye and represented the southernmost extent of Wu rule. The area had numerous indigenous Yue tribal chieftains, each holding mountain strongholds, and any misstep by court-appointed officials could easily spark a Yue uprising. In the eleventh year of Chiwu (248), Yue people in Jiuzhen Commandery stormed several county seats, and the unrest spread northward into Jiaozhi proper, throwing the entire Jiaobu Inspector's jurisdiction into turmoil. At that time Lu Yin had just extricated himself from the vortex of the political struggle around Crown Prince He — he had once been imprisoned and tortured "with all manner of sufferings, yet never altered his testimony," and was subsequently posted out as Military Commander-Inspector of Hengyang [c:17985]. Sun Quan's choice of Lu Yin to go south and administer Jiaozhou reflected both confidence in his integrity and trustworthiness, and also a political calculation to move this capable official, who had been caught up in the Ergongzhizheng, away from the storm swirling at court.
Key Figures
The executor, Lu Yin, was then around his early forties — a leading figure of the Wu Commandery Lu clan, of the same family as Lu Xun and Lu Kang. The decision-maker, the late-period Sun Quan, was in the final phase of suspicion and mistrust that preceded the Ergongzhizheng, deeply sensitive to factional struggles at court, yet paradoxically clear-headed and decisive in his personnel deployment of frontier commanders. The targets of the pacification, led by the Gaoliong chieftain Huang Wu, were locally powerful figures commanding household retinues of several thousand; the more than fifty thousand Yue households that submitted covered most of the mountain commanderies of Jiaozhou. Afterward, the Cangwu Jianling bandits were also suppressed, and in total some eight thousand able-bodied men were recruited [c:17985] — a considerable figure, equivalent to an entire commandery's main force of regulars.
Core Issue
What most merits analysis about Lu Yin's mission is his choice of methods: in the standard court response to Yue uprisings in Jiaozhou, the first step had typically been to project heavy force, intimidate, and destroy the chieftains' strongholds. Lu Yin did the opposite: upon entering the territory he initially eschewed force, instead "explaining the kindness and trustworthiness of the court and diligently promoting pacification and absorption," using credibility to open the situation [c:17985]. The viability of this approach rested on three judgments: first, the indigenous Yue tribal groups had no capacity to annex Wu territory, and uprisings were mostly reactions to oppressive local officials; second, the chieftains were not united among themselves, and if the mainstream forces accepted pacification the rest would automatically be isolated; third, the court's "sincerity," if backed by material rewards, could establish credibility in the shortest possible time. All three judgments proved accurate in execution: Huang Wu and over three thousand households submitted first, then more than one hundred chieftains and over fifty thousand households gradually submitted in turn, and even the most remote and intractable border tribes "all came to pay homage." The pacification costs were far lower than a purely military campaign, and left no lasting hatred in its wake.
Political Consequences
The direct result of Lu Yin's pacification of Jiaozhou was a substantial increase in Sunwu's actual control over the Lingnan region; the fiscal and military manpower resources of the late Chiwu period were thereby expanded — with approximately eight thousand troops recruited in total, equivalent to half a commandery's standing force. Lu Yin himself was granted the additional title of General Who Pacifies the South, becoming the bridge figure between the Wu court and the various Yue peoples of Lingnan. From a longer perspective, this pacification formed the foundation that allowed Sunwu to stably hold Jiaozhou in its later period and to profit from maritime trade in rare and exotic goods; the stability of Jiaozhou was also one of the hidden resources enabling Sunwu to survive more than ten years longer than Shuhan. Lu Yin's reputation during his tenure in Jiaozhou also established a long-lasting network of personal connections for the Lu clan in Lingnan; by the time of Lu Kang's generation, certain deployments on Wu's western front still benefited from these ties.
Counterfactual Analysis
If Sun Quan had instead sent a purely military-minded figure like Zhu Ran or Zhuge Ke south with heavy troops to suppress Jiaozhou by force, pacification might have been achieved within a year, but the price would have been pushing chieftains who could have been pacified into outright hostility; Lingnan would have remained in a state of half-rebellion and half-submission for a long time, requiring the court to mount campaigns year after year, with a steep rise in fiscal burden. If Lu Yin had been recalled mid-mission by a new round of the Ergongzhizheng — a real risk, given that he was a core figure of the Crown Prince's faction — then the pacification of Jiaozhou might have dragged on into the late Chiwu or even the Taiyuan period, precisely when the Wu palace was undergoing violent upheaval, and Lingnan might have slipped entirely out of control. In retrospect, Luyinpingjiaozhou was one of the few actions in Sunwu's later period that could genuinely be called "optimal in cost–benefit terms," and stands as an early classic case in the history of Chinese frontier governance of using "trust" in place of "force."