Among the Twelve Deceptive Stratagems recorded in The Art of War · Initial Estimations, Sun Tzu put forward a lethal psychological warfare tactic: Divide the united enemy (親而離之).
1. What Does “Divide the United Enemy” Mean?
The core rule is clear: Never launch a head-on attack when the enemy maintains tight internal unity and harmonious relations between rulers and generals. Instead, generals should create suspicion, conflicts and mutual distrust through deliberate alienation schemes. The goal is to collapse the enemy’s military power from the inside, rather than defeating their army from the battlefield outside.
Essentially, this strategy amplifies inherent interest conflicts and personality flaws hidden inside the rival camp. It helps commanders gain overwhelming strategic advantages with minimum military cost. Recorded in Records of the Grand Historian written by Sima Qian, Chen Ping’s famous alienation scheme against Xiang Yu during the Chu-Han Contention serves as the most classic and convincing historical demonstration of this timeless military wisdom.
2. Background: Liu Bang’s Deadly Crisis in Xingyang
In 203 BCE, Liu Bang, the founder of the later Han Dynasty, was trapped by Xiang Yu’s powerful Chu army inside Xingyang City. The Chu forces completely cut off Han’s supply routes. Food ran out rapidly, and the Han army faced total collapse and annihilation.
Facing overwhelming military pressure, Liu Bang’s advisor Chen Ping made an accurate judgment of Chu’s fatal internal weakness. As officially recorded in Records of the Grand Historian · Biography of Chen Ping: Xiang Yu was extremely brave but arrogant, suspicious by nature and easy to believe rumors. Meanwhile, Fan Zeng, Xiang Yu’s top loyal advisor also called the Second Father, always gave blunt lectures and strict advice to Xiang Yu. Hidden contradictions had long existed between the monarch and his chief strategist.
Chen Ping proposed a targeted counter-plan and asked Liu Bang for 40,000 catties of gold to fully implement a double-cross scheme. Trusting his advisor completely, Liu Bang gave Chen Ping full power, allowing him to spend the gold freely without asking for any expenditure reports.
3. Chen Ping’s Alienation Stratagem
Step One: Spread Rumors to Sow Initial Suspicion
Chen Ping bribed numerous spies serving in the Chu army with massive gold. These spies spread destructive rumors across the entire Chu camp:
“Senior generals including Zhongli Mo had made countless military achievements but never received fiefdoms or noble titles. They planned to secretly cooperate with the Han army, destroy the Xiang clan and divide Chu’s territory for themselves.”
These rumors successfully planted seeds of doubt in Xiang Yu’s heart. He began to distrust his most loyal frontline generals and split his core military team from the very beginning.
Step Two: Humiliate Chu Envoys to Confirm Doubt
After suspecting his generals, Xiang Yu sent official envoys to the Han camp to investigate the real situation. Chen Ping directed a delicate psychological trick on the spot.
First, he ordered servants to prepare a supreme grand sacrificial feast with complete cattle, sheep and pork, namely the highest-standardTailao Banquet. Chen Ping pretended to be respectful and asked actively whether the envoys were sent by Fan Zeng.
When the envoys replied that they were dispatched by Xiang Yu instead of Fan Zeng, Chen Ping instantly changed his facial expression. He ordered servants to remove all delicious fine food immediately and replace the feast with rough, humble meals.
Insulted and confused, the Chu envoys reported every detail to Xiang Yu after returning to the Chu camp. Fully convinced that Fan Zeng had secretly colluded with the Han army, Xiang Yu rejected all military advice from Fan Zeng without hesitation.
4. Irreversible Result: Chu Lost Its Most Important Strategist
Realizing that Xiang Yu would never trust him again and the overall situation was hopeless, a heartbroken Fan Zeng voluntarily resigned and returned to his hometown. Suffering from severe ulcer caused by anger and depression, Fan Zeng passed away halfway on his journey home.
With merely 40,000 catties of gold, Chen Ping successfully made Xiang Yu abandon his most loyal advisor and split his own core command team. The Chu army lost its most crucial strategic brain, and its overall decision-making ability declined sharply. This successful psychological warfare laid a solid foundation for Liu Bang’s final victory in the Battle of Gaixia later.
5. Core Strategic Enlightenment from This Classic Case
This famous historical event reveals the core essence of “divide the united enemy”: Attacking the mind is superior to attacking soldiers on the battlefield. A successful alienation scheme does not rely on perfect lies, but on accurate insight into the opponent’s inherent personality flaws. It forces the enemy to destroy themselves through their own suspicion and distrust.
Mutual trust is the strongest defense line for any team. Once internal trust collapses, no powerful army or strong alliance can maintain long-term stability, and internal collapse will follow inevitably.
6. Other Famous Historical Cases Proving This Military Wisdom
Sun Tzu’s stratagem of alienation has been verified repeatedly throughout Chinese military and political history.
Case 1: Tian Dan alienated King Hui of Yan and Yue Yi (Warring States Period).
General Yue Yi conquered dozens of Yan cities and posed a huge threat to Qi. Qi general Tian Dan spread rumors that Yue Yi intended to claim the Qi throne independently. King Hui of Yan, who was already suspicious, dismissed Yue Yi immediately. Qi successfully defended the city of Jimo and survived the national crisis.
Case 2: Huang Taiji alienated Chongzhen and Yuan Chonghuan (Late Ming Dynasty).
7. Conclusion
Powerful external military forces can hardly defeat a united enemy. However, internal suspicion, misunderstanding and broken trust are always the deadliest weapons to destroy a powerful team. For thousands of years, Sun Tzu’s psychological warfare wisdom has crossed dynasties, remaining valuable guidance for ancient wars, modern military confrontations and even modern team competition worldwide.
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