The Gathering Storm: Prelude to Catastrophe

In the ninth year of the Zhengda era (1232), the Jin Dynasty faced an existential crisis. The Mongol Empire, under the relentless leadership of Ögedei Khan, had already dismantled much of northern China’s defenses. The catastrophic defeat at the Battle of Sanfengshan in January 1232 shattered the Jin’s last elite army—200,000 troops annihilated in a single night. When news reached Nanjing (modern-day Kaifeng), the Jin capital, Emperor Aizong reportedly collapsed into despair. Court records describe a ruler broken by grief: he wept openly with his consorts, attempted suicide by hanging, and was only saved by palace attendants. At one point, standing atop a palace tower, he gazed at the smoke rising from the surrounding countryside and nearly threw himself to his death before being restrained.

This was not merely a military disaster but a psychological turning point. The Jin Dynasty, once a formidable power that had ruled northern China for over a century, now teetered on the brink.

The Emperor’s Last Gambit: Reforms and Desperation

On the 19th day of the first lunar month, a shaken Emperor Aizong emerged to address his people. At Chengtian Gate, he issued a sweeping pardon and a remarkable “Edict of Self-Reproach,” announcing a new era name: Kaixing (“Opening Prosperity”). Though the text of the edict is lost, contemporary accounts suggest it was a masterpiece of penitential rhetoric, drafted by the scholar Zhao Bingwen. Its emotional resonance was so profound that even commoners in the streets reportedly memorized and recited it. In isolated strongholds like Luoyang, garrisons wept upon hearing the proclamation—a rare moment of collective mourning for a dying regime.

Yet symbolic gestures could not reverse the tide. Military advisors urged a counterattack while the Mongols were exhausted from their recent campaign. Instead, the chancellor Wan Yan Baisha (also known as Cheng Yi) opted for a defensive strategy, ordering laborers to breach dikes along the Yellow River in a desperate bid to flood the surrounding plains and stall the Mongol advance. The plan backfired: Mongol cavalry ambushed the work crews, slaughtering nearly 10,000 conscripts. Only a few hundred staggered back to the city.

Fortifying a Doomed Capital

By February, Nanjing scrambled to prepare for siege. Watchtowers, artillery platforms, and defensive barriers rose along the walls. Emperor Aizong established emergency ministries for logistics and engineering, appointing seasoned commanders like Wan Yan Anchuhu and Liu Bogang to oversee the defenses. But the city faced an insurmountable problem: manpower.

With the field army obliterated, Nanjing’s garrison numbered fewer than 40,000—barely one soldier per crenellation on the sprawling walls. The ancient military theorist Mozi had warned that “a large city with few defenders” was indefensible. Forced to improvise, authorities conscripted refugees and civilians, swelling the ranks to a nominal 200,000 (though likely half that). Each recruit received a meager ration of 1.5 dan of millet monthly.

The city’s defense was organized by cardinal directions, with元帅 (marshals) assigned to each sector: Li Xin (east), Wan Yan Xienian Abu (west), Fan Zhengzhi (south), and Hesujia Pusunian (north). Troops wore colors corresponding to the Five Elements (blue for east, red for south, etc.), while a 4,000-strong rapid reaction force, the “Flying Tiger Army,” stood ready to plug breaches.

Life Under Siege: A Descent into “Total War”

The siege of Nanjing exemplified what modern historians term “total war”—a state where civilian and military life merge under relentless pressure. The city’s transformation followed patterns seen from ancient China to medieval Europe:

– Military Discipline: Guards ate at their posts; movement required special permits. Even bathroom breaks were regulated: sentries went in pairs, mouths gagged to prevent conversation. Violators faced summary execution.
– Civilian Sacrifice: Private property—grain, livestock, even timber from homes—was confiscated for defense. Identity tags tracked every resident, with women subjected to humiliating foot inspections.
– Social Control: Public gatherings, weddings, and funerals were banned. The Mozi classics forbade even “three people standing together” or “weeping in public.” Dogs and chickens were slaughtered silently to avoid alerting enemies.

The psychological toll was crushing. Nanjing, already strained by an influx of refugees (including 500,000 soldiers’ families relocated earlier), became a tinderbox of paranoia. Neighborhoods organized into mutual surveillance units, where one household’s suspicion could doom another. Rumors of Mongol infiltrators—disguised as monks, beggars, or “honest folk”—fed a climate of fear.

The Illusion of Diplomacy and Final Betrayal

In March, Mongol forces encircled Nanjing with a 150-li (45-mile) siege wall, complete with towers and a 10-foot moat. Emperor Aizong, perhaps hoping for respite, pursued negotiations. He enfeoffed his nephew Wanyan Eke as Prince of Cao to send as a hostage. His uncle, Prince Mi, tearfully offered to go instead but was refused.

The diplomatic mission collapsed spectacularly. Despite initial assurances, Mongol general Subutai reneged once Prince Cao entered his camp, declaring he would send the hostage to Ögedei Khan but continue attacking. As Mongol sappers filled the moat unopposed (under orders from Wan Yan Baisha to “avoid provoking” the enemy), furious Jin soldiers could only beat their shields and shout protests.

Aizong’s morale-boosting tour of the walls became a tragic farce. Crowds thronged to see their emperor, some accidentally brushing his robes in the chaos. When soldiers begged permission to fight back, Aizong pleaded for patience: “I would bow and pay tribute if it spares my people.” But as arrows finally flew on March 23, the Mongols responded by driving human shields—captives and civilians—into the moat under a hail of Jin arrows. The moat was soon paved with corpses.

Legacy: The Siege as Microcosm of Collapse

Nanjing held out for months before famine and disease forced surrender. The siege encapsulated the Jin Dynasty’s fatal weaknesses:

1. Strategic Missteps: Flooding the Yellow River mirrored earlier Jin blunders, sacrificing civilians for fleeting tactical gains.
2. Leadership Crisis: Aizong’s vacillation between defiance and despair eroded morale. His poignant public moments couldn’t offset poor decisions.
3. Societal Fractures: The siege exposed tensions between elites, soldiers, and refugees—divisions the Mongols expertly exploited.

For historians, Nanjing’s fall (1233) marked more than a regime’s end. It exemplified how sieges—part military contest, part psychological ordeal—could unravel civilizations. The Jin’s fate echoed the Khwarezmian Empire’s collapse under Genghis Khan: even formidable walls crumble when defenders lose the will to endure.

Today, the siege survives in fragments—a grieving emperor’s edict, a soldier’s defiant cry, the silent filling of a moat—reminders of how empires end not with a single battle, but through a thousand cuts to body and soul.