Stratagem No. 03 第三计 Winning stratagems (胜战计)
Kill with a borrowed knife
Literal
Borrow a knife, kill a person.
Let a third party, or the enemy’s own suspicion, do the harm, and keep your hand off the weapon.
Source line
敌已明，友未定，引友杀敌，不自出力，以损推演。
Traditional 敵已明，友未定，引友殺敵，不自出力，以損推演。
The enemy is already clear, and the ally is not yet committed. Draw the ally on to kill the enemy. Do not spend your own strength. This is worked out from the hexagram Sun (Decrease).
Icons working translation — draft, pending review
The hexagram Sun (Decrease) is read here as a way of getting a result by giving something up, or by not spending yourself. You decrease your own effort and let another party’s force fall on the enemy. The ally in the line is not yet decided, so the work is to point them.
三十六计 · Chinese Wikisource edition (public domain)
Meaning
Kill with a borrowed knife means removing an opponent through someone else’s strength. The enemy has already shown themselves. A second power is in play and has not chosen a side, or has reasons of its own to strike. You supply the reason, the rumour, the permission or the alliance, and you do not do the killing. The gain is double. Your strength is untouched, and the blame, or the blood, sits with the hand that held the knife.
The method is colder than a simple alliance. An ally who fights beside you shares the cost and the credit. A borrowed knife is a force you aim and do not join. It can be a rival of your rival, a partner you inflame, or the opponent’s own court, turned against its best people by planted suspicion. The hexagram’s decrease is your decrease: you accept that the blow will not be yours, and that you will not control every consequence of a hand you do not command.
The story
Duke Huan of Zheng and the state of Kuai
Mixed
Han Feizi, writing in the third century BC, tells this of Duke Huan of Zheng, in the last years of the Western Zhou. Huan wanted the small state of Kuai. He did not begin with an army. He asked for the names of Kuai’s boldest and ablest men, then wrote those names against grants of Kuai’s best fields and against titles, as if Zheng had already bought them. The lists were buried outside the city gate, with a chicken and a pig killed over them in the form of a covenant.
The ruler of Kuai took the buried alliance for proof of a plot inside his own court. Han Feizi says he killed his good ministers. Huan then attacked, and took Kuai. The knife was Kuai’s. Zheng supplied only the paper, the grave and the timing. The able men who might have defended the state were gone before the army arrived, removed by the one person who had most need of them.
Zheng’s move east, onto the lands of Kuai and neighbouring Guo, is part of the historical tradition around the fall of the Western Zhou. The buried covenant is Han Feizi’s story, told centuries later as a political lesson, and it is not in the Spring and Autumn annals. Later chronologies often place the actual end of Kuai under Huan’s son, Duke Wu, after Huan’s death in 771 BC. Read the ruse as the stratagem’s chosen illustration, and the date of the conquest as unsettled.
The ruse is Han Feizi’s anecdote; Zheng’s eastward move is historical, while the end of Kuai is often dated to Duke Wu, after 771 BC.
Sources
- Han Feizi 韩非子, Neichu shuo xia 内储说下
Myth check
The phrase is sometimes taken to mean hiring an assassin or a proxy army and nothing more. The classical case is subtler: the victim’s own side is induced to destroy itself. The stratagem is not in the Art of War.
Modern application
In a competition with three parties, the borrowed knife is the introduction you do not have to make twice. You let a regulator, a customer, a journalist or a rival’s own partner see a fact that hurts the opponent, and you stay off the complaint. The pattern is common in a workplace where two seniors already distrust each other: a carefully timed piece of true information does more than a direct attack, and it leaves your name off the argument.
The danger is the knife’s independence. A third party that strikes for its own reasons may not stop where you hoped, and may turn next to you. The practical test is whether you still benefit if the blow is heavier, slower or messier than the one you pictured. If you need the outcome to be precise, this is the wrong tool. Precision belongs to a hand you command.
Takeaways
- Identify who already has a reason to strike your opponent.
- Give them the occasion. Do not do the striking yourself.
- Assume the borrowed hand will not stop on your signal.
How to counter it
When a convenient dossier, rumour or ally appears just as a rival needs you weakened, ask who gains if you act on it. Do not destroy your own best people on evidence you did not gather.
Questions
What does kill with a borrowed knife mean?
It means getting an enemy removed by a third party’s strength, or by the enemy’s own suspicion, without spending your force. The manual derives it from the hexagram Sun, Decrease. In Han Feizi’s anecdote, Duke Huan of Zheng plants a fake alliance so the ruler of Kuai kills his own best ministers, and then Zheng attacks.
Is kill with a borrowed knife from Sun Tzu?
No. It is the third of the Thirty-Six Stratagems, a manual whose compiler is unknown and whose text is not the Art of War. The illustration usually attached to it comes from Han Feizi, a Warring States book of political argument, and concerns Duke Huan of Zheng and the state of Kuai.