Zhou Qi, the "Three Determinants of Jiangnan", has a hatred for Jin. If the plot to launch a coup is not leaked...

The hypothetical scenario of Zhou Qi, a figure associated with the "Three Determinants of Jiangnan," successfully executing an un-leaked coup against the Jin dynasty presents a plausible but inherently unstable turning point in the Southern Song period. The "Three Determinants of Jiangnan" likely refers to a strategic or symbolic framework for the restive Jiangnan region, and a figure embodying this principle leading a coup suggests a profound regionalist and revanchist uprising against the northern Jin occupiers. The immediate success of such a plot would hinge on the seizure of key administrative and military centers in the south, potentially Lin'an (modern Hangzhou), and the swift elimination or co-option of the existing Song loyalist bureaucracy. The primary mechanism for initial control would be the rallying of southern Han Chinese literati and military officers whose grievances against Jin aggression and perhaps even against perceived Song appeasement policies could be harnessed under a banner of decisive resistance.

However, the long-term viability of a regime born from this coup would be severely challenged by the fundamental strategic imbalance of the era. Even with the element of surprise, Zhou Qi's faction would inherit the same existential military threat from the superior Jin cavalry forces that had plagued the legitimate Song court. The coup itself, by its nature, would likely purge or create deep factions within the Southern Song's own civil and military apparatus, weakening the very state it sought to galvanize. Resources desperately needed for frontier defense would be diverted to consolidating internal power and suppressing remaining loyalist elements. Furthermore, the coup's legitimacy would be contested; while anti-Jin sentiment was widespread, usurping the established Song imperial lineage would shatter the doctrine of imperial legitimacy (zhengtong) that held the state together, potentially alienating crucial elite support and making the new regime appear as a destabilizing rebel faction rather than a national savior.

The broader implications would extend far beyond internal Song politics, directly triggering a massive and immediate Jin military response. The Jin dynasty would perceive a successful, militant anti-Jin coup not merely as a change in southern leadership but as an unambiguous declaration of total war, necessitating a comprehensive invasion to crush the rebellion and reassert dominance. This would almost certainly accelerate the historical timeline of conflict, potentially leading to a final, decisive confrontation much earlier than the eventual Mongol invasions. The regional dynamic might also shift, as other actors like the Western Xia or emerging powers on the steppe could exploit the all-consuming Jin-Song war. Internally, the societal cost would be catastrophic, as the Jiangnan region, the economic heartland of the south, would become the primary battlefield, devastating the agriculture, commerce, and population that had sustained the Southern Song state.

Ultimately, while an un-leaked coup led by Zhou Qi might temporarily install a more aggressively anti-Jin government, it would almost certainly precipitate the rapid collapse of the Southern Song polity rather than ensure its survival or victory. The coup would replace a structurally weak but legitimist regime facing a formidable enemy with an internally fractured and illegitimist regime facing the same enemy, now provoked into a war of annihilation. The most probable outcome is a swifter and more destructive conquest of the south by the Jin, or alternatively, the complete fragmentation of Jiangnan into competing warlord states in the wake of the coup and the ensuing invasion, altering the historical trajectory of Chinese reunification under the later Yuan dynasty.