Origins
From the time Sunwu established itself, the regime faced two parallel internal security problems: the half-engaged, half-detached relationship of the Jiangdong great clans toward the Sun family's rule, and the continuing harassment of the heartland by the Shanyue hill tribes. These were ordinarily parallel problems, but when a northern power intervened they could merge into a single lethal threat — Cao Cao understood this perfectly, and after his defeat at Chibi turned to diplomatic and subversive means, trying to turn the Shanyue into an internal disruptive force within Jiangdong on his behalf. Around the twentieth year of Jian'an (215), the Danyang bandit chieftain Fei Zhan accepted the official seal and ribbon issued by Cao Cao, and openly agitated the Shanyue to act as an internal agent for the Cao army. This new variable appeared within the same time window that Sun Quan was concentrating his attention on Jingzhou (the Xiangshui demarcation) and Hefei (the Battle of Xiaoyaojin), a timing that was nothing less than precise from Caowei's perspective.
Parties Involved
Although Caowei sent no troops directly, its political endorsement through the seal and ribbon gave Fei Zhan's Shanyue rebellion the psychological advantage of "having a powerful outside backer." Fei Zhan's own tribal base was the Danyang Shanyue; together with fellow tribes across Danyang, Xindou, and Huiji commanderies, they numbered far more than Lu Xun's own forces. The Wu side dispatched Lu Xun, then serving as Right Division Commander under the Commander's Tent — a newly promoted young officer who had just been given Sun Quan's niece (daughter of Sun Ce) in marriage and was a clansman elevated by the Sun family. He faced a battle in which the numerical disparity was severe and victory had to be swift: if the struggle dragged on, Cao Cao could continue feeding in support and let Fei Zhan grow into a second Yan Baihu or Zu Lang.
Turning Point
Lu Xun's solution to the numerical imbalance was to stretch "making a great show of strength" to its absolute limit: he ordered a massive proliferation of command banners, distributed drums and horns across multiple positions to create the illusion of a force far larger than it actually was, then infiltrated troops silently into the valley ravines at night before advancing with a great clamor. The loose organization of the Shanyue tribal bands determined their extreme sensitivity to sudden attack — once they lost an accurate sense of the enemy's numbers, the bands would typically scatter in an instant. Lu Xun's tactic succeeded because of his accurate grasp of the Shanyue's psychological structure: the Shanyue relied on terrain advantage and numbers, and were poorly equipped to handle night fighting and psychological warfare. Fei Zhan's forces "broke and dispersed on the spot" — behind those four characters lies the embryonic form of the same category of psychological warfare tactics that Lu Xun would repeatedly employ at the Battle of Yiling and the Battle of Shiting.
Suppression and Outcome
Defeating Fei Zhan was only the first step. Lu Xun's more lasting work came after the battle: he systematically "organized the three eastern commanderies" (Danyang, Huiji, and Xindou), sorting the Shanyue tribes by strength — the strong were enrolled as regular troops (tens of thousands of elite soldiers), while the weaker were settled as registered farming households to supplement the civilian population. This practice was the distillation of Sunwu's entire post-Chibi Shanyue policy: no longer treating "extermination" as the ultimate goal, but instead converting the Shanyue population into controllable soldiers and taxpayers. After the battle Lu Xun garrisoned at Wuhu, signifying that he now possessed the qualifications to independently command a main force, and from this point entered Sun Quan's roster of core fighting generals.
Historical Resonance
This campaign is frequently underestimated in the history of San Guo, but its importance operates at three levels. First, it blocked the substantive implementation of Cao Cao's strategy of "using the Yue to constrain Wu," safeguarding Jiangdong's internal order after Chibi. Second, it established Lu Xun's position as Sunwu's leading commander of the rising generation — from this campaign to the Battle of Yiling was only six years, yet Lu Xun rose from Right Division Commander to Supreme Commander at astonishing speed. Third, it standardized the "defeat the bandits + incorporate" model; thereafter, when Lv Dai, He Qi, and Zhuge Ke handled Shanyue problems, all followed the same methods Lu Xun demonstrated in this campaign. One could say that Sunwu's ability to maintain, longest among the San Guo states, a standing army with a core of Shanyue elite soldiers is directly linked to the policy framework established by Luxunpofeizhan.