The Decline of the Jin Dynasty

By the early 13th century, the Jin Dynasty—once a formidable power in East Asia—had entered a period of irreversible decline. Established by the Jurchen people in 1115 after overthrowing the Liao Dynasty, the Jin initially thrived, conquering northern China and forcing the Song Dynasty to retreat south. However, by the reign of its third emperor, Wanyan Dan (完颜亶), the empire was already crumbling under internal corruption and mismanagement.

Wanyan Dan’s reign was marked by alcoholism, political purges, and neglect of governance. His successor, Wanyan Liang (完颜亮), proved even worse, engaging in mass executions of nobility, extravagant spending, and disastrous military campaigns against the Southern Song. Though Wanyan Liang was eventually assassinated and replaced by the more competent Wanyan Yong (完颜雍), the Jin’s structural weaknesses—oppressive taxation, ethnic tensions, and military overextension—remained unresolved. By the time Genghis Khan turned his gaze southward, the Jin Dynasty was a shadow of its former self.

The Man Who Knew the Jin’s Weakness

Genghis Khan’s decision to challenge the Jin was not made lightly. His confidence stemmed from insider knowledge provided by Yelü Ahai (耶律阿海), a former Jin official who defected to the Mongols. Yelü, once a mid-ranking diplomat, had met Genghis Khan during a mission and was so impressed by his charisma and vision that he abandoned his post to join the rising Mongol leader.

Yelü’s insights were invaluable. He revealed the Jin’s internal decay: a shrinking Jurchen population (just 3 million) ruling over 40 million Han Chinese, rampant corruption, and a military stretched thin by rebellions and border wars. Yet, Genghis Khan remained cautious. The Jin’s fortified cities and vast armies were unlike anything the Mongols had faced. To test the waters, he disguised a reconnaissance mission as a tribute delegation in 1209.

The Spit That Broke the Camel’s Back

The meeting between Genghis Khan and Jin envoy Wanyan Yongji (完颜永济) at Jingzhou (净州) was a turning point. Wanyan Yongji, a weak and indecisive prince, was tasked with receiving the Mongol leader. When Genghis Khan questioned why he was barred from entering Jin territory, Yongji’s advisors arrogantly dismissed him as a “barbarian.” Genghis Khan, insulted, left his tribute—a pile of ragged animal pelts—and rode off without bowing.

The final insult came in 1208 when Yongji ascended the Jin throne. His envoys demanded Genghis Khan perform a humiliating submission ritual, including kowtowing to the new emperor. Genghis Khan’s response was legendary: he spat on the ground and declared, “I thought the Jin emperor was divine, but he’s just a coward. Why should I bow to such a fool?” This act of defiance severed all diplomatic ties.

The Road to War

In 1211, Genghis Khan convened a kurultai (Mongol council) to rally support for war. His arguments were masterful:

1. Historical Grievances: He invoked the Jin’s brutal “Reduction Policy” (减丁), where Jurchen troops regularly massacred Mongol tribes to suppress their population.
2. Material Incentives: The Jin’s wealth—silver, silk, and cities—was irresistible to the nomadic Mongols.
3. Divine Mandate: After three days of solitary prayer on Burkhan Khaldun mountain, he claimed the war was sanctioned by Tengri (the sky god).

The Mongols, though inexperienced in siege warfare, were convinced. Allies like the Uighurs and Tanguts pledged support, eager to see the Jin humbled.

The Jin’s Arrogance and Downfall

When news of the Mongol mobilization reached the Jin court, Emperor Wanyan Yongji scoffed: “Our empire is vast as the ocean; the Mongols are but a handful of sand.” His confidence was catastrophically misplaced. In 1211, Genghis Khan launched his invasion, exploiting the Jin’s fractured defenses and using captured engineers to breach walls. By 1215, Beijing fell, and the Jin were forced to retreat south, beginning their irreversible collapse.

Legacy: The End of an Era

Genghis Khan’s defiance—symbolized by that infamous spit—marked the end of Jin dominance and the rise of Mongol supremacy in Asia. The war exposed the fragility of sedentary empires against nomadic mobility and psychological warfare. Culturally, it reshaped East Asia, paving the way for the Yuan Dynasty and redefining China’s relationship with the steppe.

Today, the story endures as a lesson in leadership and the perils of underestimating one’s rivals. Genghis Khan’s audacity—and Wanyan Yongji’s incompetence—remain timeless reminders of how empires rise and fall.