Background
Liubeiruchuan — Liu Bei's advance into Sichuan — was the first concrete step in Zhuge Liang's Longzhong strategy of "straddling Jingzhou and Yizhou," and simultaneously the greatest ethical paradox of Liu Bei's life. In the Longzhong plan Zhuge Liang had already identified Yizhou as a natural base: "a thousand li of fertile plains, the land of heavenly abundance, with Liu Zhang weak and dim." Yet Liu Zhang was a kinsman of the Han imperial house, and annexing a fellow clansman was insoluble under Confucian ethics. When Zhang Lu's threat to Hanzhong threw Liu Zhang into a panic in the sixteenth year of Jian'an, Zhang Song and Fa Zheng worked from within to welcome Liu Bei into the region — giving Zhuge Liang the window he needed to put the strategy into practice. Pang Tong, the most powerful "realist strategist" of that phase, cleared Liu Bei's psychological obstacles with the argument that "attacking the weak and the benighted, seizing power and then governing virtuously — this is the way of Tang and Wu" — packaging the annexation of a kinsman as the legitimate outcome of dynastic mandate and institutional transition. At this moment Liu Bei's camp completed its strategic mental shift from "dependent parasitism" to "active territorial expansion."
Key Figures
The political landscape on Liu Zhang's side fully exposed the internal fractures within the Yizhou bloc. Those who advocated welcoming Liu Bei were represented by Zhang Song, Fa Zheng, and Meng Da; those who opposed were represented by Huang Quan, Wang Lei, Li Hui, and Liu Gui. Huang Quan's remark — "Liu Bei is the heroic hawk of the age: when he served Cao Cao he plotted to harm him; when he followed Sun Quan he seized Jingzhou — with a character like that, how can one live alongside him?" — is the most accurate portrait of Liu Bei's track record. Liu Zhang's critical failure was not that he could not read Liu Bei clearly, but that he placed the ceremonial weight of shared clan blood above strategic judgment — he repeatedly answered every warning with "Xuande is my elder kinsman; why would he ever harm me?". On Liu Bei's side a clear division of roles had taken shape: Pang Tong as chief strategist, Fa Zheng as inside agent, Zhang Song as internal conspirator, and Meng Da as guide and host; civil leadership by Pang Tong and military by Huang Zhong, Wei Yan, Liu Feng, and Guan Ping — the first fully "offensive-formation" deployment since Liu Bei had established himself in Jingzhou.
Core Issues
On the surface the issue was "responding to Zhang Lu's threat and entering Shu as a defensive ally"; at a deeper level it was "completing the largest territorial annexation at the lowest possible moral cost." The entire sequence of Liu Bei's entry into Sichuan rewards careful reading as modern political history: first, he garrisoned Jiamengguan and dispensed generous patronage to win the hearts of the people, waiting for Liu Zhang's side to commit the first breach of propriety; then he manufactured strategic justification by "requesting grain rations and being refused"; finally the exposure and execution of Zhang Song and the destruction of Fa Zheng's letters triggered the open break. The elegance of this sequence lay in the fact that at every step the opposing party was maneuvered into a logically untenable position, while Liu Bei always retained the moral identity of "one compelled to strike back." Pang Tong's "seize power first, then govern virtuously" was not a hollow phrase — it precisely defined the legitimacy boundary of this entire sequence: in the act of taking one may be without benevolence, but after securing power one must govern with benevolence. This is also why, upon entering Chengdu, Liu Bei immediately conferred offices, pacified the populace, reassured Liu Zhang's former subordinates, and carried out no massacres — forming a sharp contrast with Cao Cao's slaughter at Xuzhou and Sun Quan's seizure of Jingzhou.
Political Consequences
The campaign to enter Sichuan unfolded in two phases: from Liu Bei's arrival at Jiamengguan in the seventeenth year of Jian'an to the break with Liu Zhang in the eighteenth year was the "political phase," while the eighteenth through nineteenth years saw the "military phase" of the battles at Luocheng and Chengdu. The most immediate political consequence was that Shuhan's geographic territory took its first fully formed shape — Jingzhou, Yizhou, and Hanzhong (seized a year later) together constituted a defensive empire of "mountains as shield and rivers as arteries." The heaviest price was Pang Tong's death in battle outside Luocheng, which forced Zhuge Liang to personally lead Zhang Fei and Zhao Yun into Sichuan, leaving only Guan Yu alone to hold Jingzhou — a structural setup for the chain of events in the twenty-fourth year of Jian'an when Guan Yu's northern campaign received no reinforcement and Jingzhou fell. From the perspective of power structure, after the entry into Sichuan Shuhan crystallized into a three-layer formation: "Jingzhou faction (Zhuge Liang, Ma Liang, Pang Tong's former subordinates) + Eastern-province faction (Fa Zheng, Li Yan, Meng Da) + Yizhou native faction (Huang Quan, Qiao Zhou, Zhang Yi)" — tensions among these three groups would run through Shuhan to the very end.
Counterfactual Analysis
If Liu Zhang had heeded the remonstrations of Huang Quan and Wang Lei and refused to welcome Liu Bei, Liu Bei's camp would have been pinned between Jing and Xiang, and the Longzhong strategy of "straddling Jingzhou and Yizhou" could not have advanced — the most realistic evolution would have been Liu Bei pivoting to an alliance with Zhang Lu or pushing south toward Jiaozhou, leaving Shuhan geographically smaller and more fragile. If Pang Tong had not died at Luocheng, Shuhan's two most decisive strategists would have been alive simultaneously in the middle and late periods (Pang Tong assisting Liu Bei in Sichuan, Zhuge Liang holding Jingzhou) — Jingzhou might not have had to rely on Guan Yu alone, Guan Yu's northern campaign would have had support, and the entire collapse of the twenty-fourth year of Jian'an might have been averted. If Liu Bei had not listened to Pang Tong and had instead persisted in his "refusal to betray righteousness", Shuhan would have forfeited all strategic initiative — the result would not have been a moral victory but being picked apart one by one by Cao Cao or Sun Quan. Understanding this point is also understanding why Liu Bei's "benevolence and righteousness" were never the strategy itself but always a layer of packaging around the strategy; Pang Tong was the man who temporarily removed that packaging to allow the act of territorial seizure to be completed — and he paid for that act with his life.