Background
In the sixth year of Jian'an (201), after his defeat at Runan, Liu Bei went north and sought refuge in Jingzhou, where Liu Biao placed him at Xinye as a buffer against Cao Cao to the north. The arrangement was nominally a host receiving a guest; in substance it positioned Liu Bei as a "shield": facing Cao Cao from the north while being hemmed in internally by the Cai and Kuai clan networks. In the five years Liu Bei spent in Jingzhou, his relationship with Liu Biao's government grew increasingly delicate — Liu Biao relied on his prestige while remaining wary of his "ambitious hero" character. The Romance of the San Guo compressed this long period of political unease, stretching over several years, into the dramatic spectacle of a single banquet and a single galloping horse — reflecting beneath the surface the irreconcilable structural contradiction between a dependent guest-general and the local magnates.
Key Figures
Liu Bei at this time had no fixed base; his chief assets were the political title of "kinsman of the Han imperial house" and the battle-hardened veterans Guan Yu, Zhang Fei, and Zhao Yun. His position in Jingzhou was in no essential way different from his earlier situations of dependence on Lv Bu, Cao Cao, or Yuan Shao — a guest in name, a hostage in fact. Cai Mao was the representative of the local Jingzhou magnate Cai clan; he was both the elder brother of Liu Biao's second wife, Lady Cai, and the practical controller of the Jingzhou navy, and harbored an impulse to eliminate any outside force that threatened the Cai clan's standing. Yi Ji came from Liu Biao's government but was not aligned with the Cai faction; the Romance arranges for him to risk himself to pass on a warning — in essence using a specific individual to give human form to the historical truth that "the Jing-Xiang literati were not monolithic." Zhao Yun at this point served as Liu Bei's closest personal military protector and is a safety net always present in the background of the Tanxi sequence, though never appearing on stage.
Core Issues
The political question this sequence seeks to answer is how a client lord, caught in the gap between a hesitant patron and a hostile clan network, can survive. Liu Biao's attitude was always "no answer — only a shaking of his head": unwilling to personally dispose of Liu Bei and earn a bad name, yet unable to stop the Cai clan from moving. Cai Mao's scheme was to use the occasion of a great assembly of the officials to execute the deed through the appearance of public deliberation, packaging a private grudge as collective decision-making — the typical purge method of medieval local magnates. Liu Bei's response was to "leave first and argue later": better to breach etiquette and abandon the banquet than to sit at the table in a political ambush and await death. This judgment is entirely consistent with his earlier logic of abandoning Xuzhou and giving up Runan — survival comes first, reputation can be discussed afterward.
Political Consequences
In the terms of the novel's narrative, Yuematanxi was a turning point in Liu Bei's fortunes: it converted a political hunt into a mythic miracle of "destiny's chosen one," with the prophecy of "the dilu horse brings misfortune to its master" reversed into "the dilu horse saves its master". This narrative serves to reinforce Liu Bei's color of "true mandate." In terms of the political landscape of Jingzhou, this episode did not genuinely dissolve Cai Mao's enmity toward Liu Bei — it instead caused both sides to openly tear their masks off, planting the seeds for what followed: Liu Biao's death from illness, Cai Mao's backing of Liu Cong's succession, and Liu Bei's forced southward flight. The Tanxi incident also prompted Liu Bei to visit the Water Mirror Master Sima Hui, which in turn led to Xu Shu's recommendation and Sangumaolu — the central talent-acquisition thread running through the middle portion of the entire novel. It is a critical hinge in the novel's structure.
Counterfactual
If Cai Mao's ambush had left no retreat through the western gate, or if the "three-zhang leap" at Tanxi had not appeared as a marvel, Liu Bei's most likely fate would have been death in the outskirts of Xiangyang. In that case, the Guan-Zhang-Zhao Yun martial contingent would probably have scattered across Jing-Xiang; Zhuge Liang and Pang Tong would have had no occasion to encounter Liu Bei; Jingzhou on the eve of Chibi would have only the force of Liu Cong — the resistance Cao Cao would have met when he swept south would have been weaker, and the entire tripartite division of the realm might never have taken shape. On the other hand, if Liu Biao at the time had decisively chosen a side — either genuinely trusted Liu Bei and suppressed the Cai clan, or openly collaborated with Cao Cao to eliminate Liu Bei — Jingzhou would have entered a period of stability under a single dominant will before 208, and the chain reaction of Liu Cong rapidly surrendering to Cao Cao and Liu Bei being forced to flee to Jiangxia would not have occurred. The leap at Tanxi was at once a dramatic legend and the Romance's concentrated expression of the theme of "how fate and chance together shape history."