The Grand Design for Conquest

In 280 CE, the Jin dynasty launched a meticulously planned campaign to conquer the rival state of Wu, marking the final chapter in China’s Three Kingdoms period. Emperor Sima Yan, following a strategy devised by the late general Yang Hu, mobilized 200,000 troops across six coordinated fronts:

1. Eastern Front: Sima Zhou advanced from Xiapi toward Tuzhong.
2. Central Front: Wang Hun (a royal in-law) marched from Shouchun toward the Yangtze crossings.
3. Southern Front: Wang Rong (a trusted ally) pushed from Xuchang toward Wuchang.
4. Western Front: Hu Fen (a veteran commander) moved south along the Han River to Xiakou.
5. Naval Offensive: Du Yu (Sima Yan’s uncle-in-law) targeted Jiangling from Xiangyang.
6. Riverine Assault: The aging but formidable admiral Wang Jun led an armada down the Yangtze from Yi Province.

To manage logistics, Sima Yan appointed Zhang Hua as quartermaster-general. Yet the emperor’s most revealing decision was naming his political rival Jia Chong as nominal supreme commander—a move laden with hidden calculations.

The Chessboard of Distrust

Sima Yan’s deployment reflected deep-seated paranoia:
– Containing Wang Jun: The 70-year-old admiral commanded Jin’s largest fleet after years of autonomous rule in Yi Province. His potential defection haunted Sima Yan, who stationed Jia Chong at Xiangyang—a strategic choke point to intercept any rebellion.
– Balancing Factions: By making the upstart Yang family Jia’s deputies, Sima Yan ensured they’d share credit for victory while letting Jia bear blame for failure.
– Political Theater: Victory would rehabilitate Jia’s anti-war stance; defeat would discredit him. As Sima Yan quipped: “Jia has spent a lifetime dodging blame—do you really think he’ll take responsibility now?”

The Campaign Unfolds

Initial progress was uneven:
– Wang Hun captured Xunyang but stalled at the Yangtze.
– Du Yu besieged Jiangling without breakthrough.
– Wang Jun’s fleet remained ominously silent.

Jia seized the moment to undermine the campaign, demanding Zhang Hua’s execution for “reckless warmongering.” Sima Yan defused the crisis with remarkable restraint: “The campaign was my decision. Zhang merely agreed with me.”

The Turning Tide: Wang Jun’s Armada

The stalemate shattered when Wang Jun’s “floating fortresses”—ships so massive horses could gallop on deck—emerged from the Three Gorges. Overcoming Wu’s river defenses with fire rafts and iron-cutting torches, the fleet:
– Broke through the Iron Chain Barrier (February 1)
– Captured Xiling (February 3)
– Stormed Leixiang (February 5), where 800 Jin commandos infiltrated the city with retreating Wu troops

Du Yu, recognizing Wang Jun’s unstoppable momentum, sent a fateful letter: “Press onward to Jianye. Sail your fleet up the Huai and Yellow Rivers to Luoyang—claim immortality!” This olive branch, which Wang forwarded to Sima Yan as insurance, became the campaign’s linchpin.

The Fall of Wu

As Wang Jun raced toward Jianye:
– Wu’s last army was annihilated at Niuzhu, with chancellor Zhang Ti dying defiantly: “Better to fight than wait for our morale to collapse!”
– Wang Hun deliberately delayed crossing the Yangtze, hoping to claim final glory.
– Wang Jun, ignoring orders to halt, seized Jianye on March 15. Wu’s emperor Sun Hao surrendered with the same rope-and-coffin theatrics as Shu’s Liu Shan had decades earlier.

The Bitter Aftermath

Victory spawned new conflicts:
– Wang Hun vs. Wang Jun: The aristocratic Wang Hun accused the “upstart” admiral of insubordination, demanding his execution. Sima Yan mediated awkwardly.
– Political Reckoning: Wang Jun’s humble origins made him vulnerable. When Wang Hun sneered, “You’re just a petty vessel,” no courtier dared defend the admiral. Only Sima Yan’s personal intervention saved him.
– Missed Opportunities: The campaign exposed Jin’s systemic rot. As one observer noted: “Any competent commander could have conquered Wu—the state was already a rotten door waiting to be kicked in.”

The Fatal Legacy

The conquest’s political fallout proved more consequential than the military victory:
1. Factional Strife: Sima Yan’s reliance on relatives and suppression of dissent (including the suspicious death of his brother Sima You) fractured the court.
2. Militarized Princes: Fearful of both aristocrats and his own heir’s incompetence, Sima Yan empowered regional princes with unprecedented autonomy—planting seeds for the devastating War of the Eight Princes.
3. Historical Irony: The reunification meant to cement Jin’s rule instead accelerated its collapse. Within 30 years, northern China would descend into chaos, beginning three centuries of division.

As the Book of Jin poignantly notes: “The empire was unified, yet the victory felt like twilight—not dawn.” Sima Yan’s triumph, built on distrust and compromise, became history’s cautionary tale about the costs of political expediency.