The arrival of Song forces at the siege of Caizhou in 1233 marked a dramatic turning point in the final struggle between the Jin Dynasty and the Mongol-Song alliance. What had been a slow, grinding siege suddenly transformed into a fierce competition between the two allied armies—each determined to claim the honor of breaching the city walls first. This pivotal moment not only sealed the fate of the Jin Dynasty but also reshaped the political landscape of East Asia.

The Fall of the Jin Dynasty: A Desperate Last Stand

By 1233, the Jin Dynasty, once a formidable power in northern China, had been reduced to a desperate rump state clinging to its last stronghold at Caizhou. The Mongol Empire, under Ögedei Khan, had already overrun much of Jin territory, while the Southern Song Dynasty, seeking revenge for decades of humiliation, saw an opportunity to finally destroy their long-time adversary.

The Jin emperor, Aizong, had fled to Caizhou after the fall of Kaifeng, hoping to regroup and continue resistance. However, the city was ill-prepared for a prolonged siege. With dwindling supplies and no hope of reinforcements, the Jin leadership resorted to increasingly desperate measures—some bordering on the absurd—to stave off the inevitable.

The Mongol-Song Alliance: An Unlikely Partnership

The Mongol and Song forces, though historically wary of each other, found common cause in the destruction of the Jin. The Song general Meng Gong, a seasoned commander with deep experience fighting the Jin, led a disciplined army to join the siege. His forces specialized in siege warfare, and their arrival injected new energy into the campaign.

Meng Gong’s diplomatic skill was as sharp as his military tactics. He quickly established rapport with the Mongol commander Tachar, sharing feasts and even forming a ceremonial brotherhood. This uneasy alliance was held together by mutual ambition—both sides wanted to claim the glory of delivering the final blow to the Jin.

The Siege Intensifies: Psychological and Military Warfare

The siege of Caizhou was not just a battle of arms but also of wills. The Jin defenders, though outnumbered, fought with grim determination. Meanwhile, the besiegers engaged in psychological warfare—flaunting their strength, bombarding the city with propaganda, and exploiting superstitious fears.

One bizarre episode involved a self-proclaimed Daoist mystic, the so-called “Master of the Hemp Robe,” who promised to solve the city’s food shortages through esoteric fasting techniques. When his fraud was exposed, he was swiftly executed. Another Jin officer proposed outfitting warhorses with grotesque masks to terrify Mongol cavalry—a plan dismissed as impractical.

The Final Assault: Breaching the Walls

By December 1233, the Mongol and Song forces had tightened their grip on Caizhou. The Mongols breached the western walls after relentless bombardment, while the Song army targeted the southern defenses, draining the protective moat of Chai Tan.

The Jin defenders, including women disguised as soldiers, fought ferociously. Emperor Aizong himself visited the front lines, distributing his own possessions to boost morale. Yet, despite their bravery, the city’s fate was sealed. The Mongols and Song, now locked in a race to claim victory, pushed forward with overwhelming force.

The Legacy of Caizhou: The End of an Era

The fall of Caizhou in early 1234 marked the official end of the Jin Dynasty. Emperor Aizong, rather than face capture, committed suicide, and his successor ruled for mere hours before the city fell. The Mongol-Song alliance, however, proved short-lived. Within decades, the Mongols would turn on the Song, leading to the eventual conquest of all China under Kublai Khan.

The siege of Caizhou remains a vivid example of medieval siege warfare, blending military strategy, psychological manipulation, and sheer human endurance. It also serves as a cautionary tale about the fragility of alliances built on mutual enemies—a lesson that would echo through East Asian history for centuries to come.