Stratagem No. 33 第三十三计 Desperate stratagems (败战计)
Turn the enemy’s spies
Literal
The turned-spy stratagem.
Use the other side’s own mistrust, or their own agent, so they discard the person who was holding them together.
Source line
疑中之疑。比之自内，不自失也。
Traditional 疑中之疑。比之自內，不自失也。
Doubt within doubt. Alliance from within: one does not lose oneself. This is the hexagram Bi (Holding Together).
Icons working translation — draft, pending review
The sentence is the Image on the second line of Bi (Holding Together): an alliance begun on the inside does not cost you your own position. The inside is the enemy’s camp, so their bonds do the work and the doubt stays over there.
三十六计 · Chinese Wikisource edition (public domain)
Meaning
Turn the enemy’s spies means you do not only catch an agent. You use the other side’s own channels, and their own readiness to suspect each other, so that they wound themselves. The commentary’s definition is short. A spy-plot makes the enemy doubt his own people. A turned plot uses the enemy’s own spy-work to do it. The classical line calls the result doubt within doubt, and an alliance started from inside, so that you do not have to spend yourself in the open.
Sun Tzu’s chapter on spies is narrower than this entry, and older. He uses the term for an enemy spy whom you capture and employ, so that the enemy is fed what you choose. The stratagem book keeps that sense and adds the rumour that makes a ruler dismiss a loyal general. Both end the same way: the strong man on the other side is removed by his own court. You never have to fight him. The hexagram’s promise is that this kind of alliance does not lose you your own place, provided the doubt stays over there.
The story
Tian Dan and the rumour about Yue Yi, 279 BC 反间乐毅
History
Yue Yi of Yan had done what a generation of generals failed to do. Under King Zhao he had broken Qi, from 284 BC, and taken more than seventy cities. Two held out, Ju and Jimo. Tian Dan was in Jimo. Then King Zhao died, in 279 BC, and King Hui came to the throne. Hui had disliked Yue Yi since his years as heir. Tian Dan aimed the rumour at that old dislike. Yue Yi, the whisper said, wanted Yan’s throne in Qi for himself. He was slow to take Jimo because he feared being replaced and punished. Qi’s only fear was a different Yan general, under whom the city would fall at once.
King Hui sent Qi Jie to take the command. Yue Yi, who had reason to expect a worse reward than dismissal, fled to Zhao. The siege army, which had been a patient instrument in the hands of a famous general, became a new man’s army, and Tian Dan broke it. The fire-oxen attack that followed is a separate famous page of the same biography. The stratagem was the page before: a rumour sized to a suspicion the new king already owned. Yan did Tian Dan’s killing of Yue Yi’s authority. Qi never had to defeat Yue Yi in the field.
The commentary’s other historical case is Chen Ping at Xingyang in 204 BC. He asked Liu Bang for a large sum in gold and used it to spread distrust between Xiang Yu and the ministers around him. Fan Zeng, who had been Xiang Yu’s shrewdest adviser, found his plans refused, left, and died on the road. Details of the exact whisper vary. The Shiji’s spine is stable: gold, rumours of disloyalty, a king who already could be made suspicious, and a camp that dismissed the man it most needed. Same shape as Jimo, paid for in metal rather than in a story about a throne.
Tian Dan’s rumour, King Hui’s replacement of Yue Yi, and Yue Yi’s flight to Zhao are in Sima Qian’s Shiji, chapters 80 and 82, Chen Ping’s use of gold at Xingyang is in chapter 56, and the wording of the whispers is the historians’ compression rather than a transcript.
Sources
- Sima Qian, Shiji 史记, ch. 82 (Tian Dan) and ch. 80 (Yue Yi)
- Sima Qian, Shiji 史记, ch. 56 (Chen Ping)
Myth check
This is the one name on the list that Sun Tzu does use: in the Art of War’s chapter on spies, a turned spy is an enemy agent you employ, while this much later entry also covers rumours that make a ruler discard his own general, which is Tian Dan’s case. The stolen letter that dooms Cai Mao and Zhang Yun, with Jiang Gan as the courier, is the Romance of the Three Kingdoms, not the Sanguozhi.
Modern application
A partnership or a cabinet is turned when you feed a doubt its members already half believe. You rarely need a stolen document. A careful remark, passed through someone they already use as a channel, that their best operator is building a private future, is Tian Dan’s whisper. It only works if the suspicion has a history. King Hui had disliked Yue Yi for years. A rumour about a trusted stranger bounces off.
The defence is expensive and dull. Major removals should require evidence that did not arrive through a single interested channel, and the person under rumour should be able to answer it before the command changes. Organisations that dismiss their Yue Yi in a week, on a story that flatters the boss’s old grudge, have done the enemy’s campaign for free.
Takeaways
- Feed a suspicion the other side already has.
- Aim the whisper at their indispensable person.
- Do not dismiss your own key people on one channel.
How to counter it
Treat a sudden, well-shaped story about your best person’s secret ambition as a possible gift from the other side, and ask who benefits if you remove them this week, making the accuser’s channel part of the evidence. Speed of dismissal is the symptom.
Questions
What does turn the enemy’s spies mean?
It means using the other side’s own agents, or their own mistrust, so that they doubt and discard their own people. Sun Tzu used the term for an enemy spy whom you turn and feed. This later entry includes that, and also a rumour aimed at a grudge the enemy already has, as when Tian Dan in 279 BC got Yan to replace Yue Yi.
Did Zhou Yu trick Cao Cao’s spy Jiang Gan?
The banquet, the stolen letter, and the execution of Cai Mao and Zhang Yun are a plot in the Romance of the Three Kingdoms. They are not in Chen Shou’s Sanguozhi. The historical shape of this stratagem is plainer: Tian Dan’s rumour against Yue Yi, and Chen Ping’s gold-funded whispers against the ministers around Xiang Yu. Both are in the Shiji.