Law 10 tells you to run. Avoid the unhappy, avoid the unlucky, quarantine, do not take pity, and — at the end — "this law admits of no reversal. Its application is universal."
Twelve lines into the same chapter, in the margin, Miyamoto Musashi explains how to do it on purpose.
Many things are said to be infectious. Sleepiness can be infectious, and yawning as well. In large-scale strategy when the enemy is agitated and shows an inclination to rush, do not mind in the least. Make a show of complete calmness, and the enemy will be taken by this and will become relaxed. You infect their spirit. You can infect them with a carefree, drunklike spirit, with boredom, or even weakness.1
You infect their spirit. Same word, same claimed mechanism, opposite direction — and Greene prints it beside a law he declares has no reverse, without comment.
Musashi opens with the cheapest possible evidence and it is well chosen.
Sleepiness is infectious. Yawning is infectious. Nobody disputes this, nobody needs a study for it, and everyone has been on both ends.
That is the whole argument for the mechanism, and it does something Greene's chapter never manages: it establishes emotional transmission from ordinary experience rather than from a nineteenth-century courtesan and a metaphor about viruses.
Then the move: if the trivial version is real and involuntary, the strategic version is available. What you can catch, you can transmit. What you can transmit, you can transmit deliberately.
Musashi is precise about when this applies: "when the enemy is agitated and shows an inclination to rush."
So the target is already in a state — keyed up, wanting to move, ready to commit.
The instruction is "do not mind in the least." Not to counter the agitation, not to match it, not to exploit it directly. To be visibly unbothered by it.
And the result: "the enemy will be taken by this and will become relaxed."
The word taken is doing precise work. Not persuaded, not calmed down by argument. Taken — as in caught, as in something happening to them rather than something they decide.
Work out why this functions, because it is not obvious that relaxing your enemy is a good idea.
An agitated opponent inclined to rush is dangerous in one specific way: they will commit early and hard. That is bad for you if you are not ready, and it is the state in which people fight best against an unprepared defender.
But agitation is also expensive to hold. It cannot be maintained indefinitely, and it is calibrated to what the person is looking at. If the thing they are keyed up against shows no sign of being keyed up, the pitch has nothing to hold on to.
So the calm does two things at once. It denies the agitation its object — there is nothing to be agitated at. And it transmits the opposite state, because the transmission runs whether or not either party intends it.
The opponent relaxes. They relax at a moment when relaxing is wrong. And critically, they experience the relaxation as their own judgement — as having reassessed the situation and concluded it was less urgent than they thought.
That is the same structure as Law 8's bait: the target performs the decisive act and reads it as their own decision.
Musashi lists what can be transmitted: "a carefree, drunklike spirit, with boredom, or even weakness."
Three distinct states, and they are not interchangeable.
Carefree, drunklike spirit — the target stops taking the situation seriously. Useful against someone who would otherwise prepare properly.
Boredom — the target's attention degrades. Useful against someone whose advantage is vigilance, and it is the slowest of the three.
Weakness — the target's sense of their own capacity drops. The most aggressive of the three, and the one closest to what a modern reader would call demoralisation.
Musashi supplies no rule for choosing, which is a familiar shape in this build. But the three map cleanly onto three different enemy advantages — seriousness, attention and confidence — and the implied instruction is to transmit the state that neutralises whichever one your opponent is actually running on.
The presence of this passage changes the law it sits inside, in three ways.
It refutes the no-reversal claim. A reversal is exactly what this is: the law inverted, stated by a named authority, printed inside the chapter. Greene's declaration that the law is universal and admits of no reverse is contradicted by material he selected himself.
It makes the defensive advice incomplete. If infection can be deliberate, then the diagnostic — turbulent past, broken relationships, unstable careers — is looking for the wrong thing entirely. Those signs identify someone whose misery is genuine and self-generated. They cannot identify a competent operator transmitting a state on purpose, who will have a clean record and a stable career precisely because it is a tactic rather than a condition.
Law 10 warns about people who are unwell. Musashi describes people who are well and are doing this to you. The second is rarer and considerably more dangerous, and Greene's chapter offers nothing against it.
An opponent, rival or counterparty is agitated and pushing for a fast resolution.
First, check whether their urgency is real or transmitted. Before doing anything, ask whether the pressure you are feeling originated with you. Agitation arriving from outside is the first thing to identify, because catching it is involuntary and noticing it is not.
Second, decline to mirror. Musashi's "do not mind in the least" is not a performance of indifference so much as a refusal to enter the tempo. Matching an agitated counterparty confirms that the situation warrants agitation.
Third, work out what their advantage actually is. Seriousness, attention or confidence — because that determines which of the three payloads is worth transmitting, and transmitting the wrong one wastes the move.
Fourth, understand that you are degrading their judgement, not informing it. This is the honest framing. The relaxation you induce is not a correct reassessment; it is a wrong one, arrived at through contagion, which they will experience as their own conclusion.
Fifth, on the defensive side — audit your own state changes. If you have relaxed, become bored, or lost confidence in a negotiation, the useful question is not am I right to feel this but when did this start, and who was in the room.
And the plain statement: this is a technique for making an opponent misjudge a situation by transmitting a mood to them. It works because emotional states are contagious and contagion bypasses reasoning entirely. There is nothing in it that requires the target to be foolish.
Strongest support. The mechanism is grounded in an observation nobody disputes — yawning and sleepiness — and the tactical claim is a straightforward extension of it. Musashi is also a practitioner writing about his own field, which is a stronger warrant than most of what surrounds it.
Tension — it contradicts the law it is printed inside. Documented above, and it is the most direct instance in the build so far of a chapter carrying its own refutation in the margin.
Tension — no criterion for the three payloads. Familiar shape: a real distinction, drawn, then left unresolved.
Tension — no defensive half. Musashi tells you how to transmit and never how to detect. Greene's chapter tells you how to detect the wrong thing. Between them the reader gets an offensive technique and a diagnostic aimed at a different population.
🚩 SINGLE SOURCE · 🚩 SECONDARY WITHOUT PRIMARY — attributed to A Book of Five Rings, seventeenth century,2 with no translator or edition named, which matters more than usual for a Japanese text where translation choices are substantial. The English word "infect" is carrying the entire parallel to Greene's chapter, and whether the original supports that resonance is not checkable from what is printed. [POPULAR SOURCE]
Open questions.
Greene's Aggression as Loss of Control at Law 8 is the same claim in different vocabulary, and the two laws never meet.
Law 8's diagnosis: the aggressive operator is "constantly being forced to react," mistakes aggressive action for effective action, and exhausts himself. The prescription is "stay back, keep calm, and let others be frustrated by the traps you lay for them."
Musashi's target is "agitated and shows an inclination to rush" — Law 8's aggressor exactly. His method is to make a show of complete calmness. Same posture, same target, same theory of who loses.
The difference is what each thinks calm is doing.
Greene's calm is a defence. It protects your judgement, keeps you out of the reaction cycle, and lets the opponent exhaust himself against traps.
Musashi's calm is a transmitter. It reaches into the opponent and changes his state directly.
The insight the pair produces: Law 8 and Law 10 are the same law seen from two sides, and Greene built them as unrelated chapters ninety lines apart. Law 8 says calm defeats agitation by outlasting it; Law 10's margin says calm defeats agitation by infecting it. The second is the mechanism the first never supplies — Greene never actually explains why staying back frustrates an opponent rather than simply delaying him, and Musashi answers it in one line.
That is the third instance in this build of a single instruction split across two chapters with the halves unconnected, after Law 1 ↔ Law 6 and Law 3 ↔ Law 4's Reversal.
→ psychology · Positive Infection and Emotional Osmosis
Greene's own positive case: Napoleon kept Talleyrand close to absorb the manners, wit and aristocratic charm he lacked, and "many of the rough edges were smoothed by his constant association." The instruction is to associate deliberately with people whose qualities you want.
Both passages describe deliberate use of the same susceptibility, and they differ on who the beneficiary is.
Napoleon runs it on himself. He arranges his own exposure, accepts the transmission knowingly, and is improved by it. The other party loses nothing.
Musashi runs it on someone else, without their knowledge, to degrade them.
The insight neither page produces alone: emotional contagion is genuinely value-neutral, and the moral weight sits entirely in the direction of consent — self-administered exposure is education, and unilateral transmission is an attack, with no difference in the mechanism whatsoever.
Which exposes something about Law 10's structure. Greene has all three cases in one chapter: contagion suffered (Lola's lovers), contagion self-administered (Napoleon), and contagion weaponised (Musashi, in the margin). He builds the chapter entirely on the first, mentions the second approvingly, and never acknowledges the third — so the reader is handed a law about avoiding sick people, when the material supports a general theory about a channel that runs in every direction.
→ history · Togo and the Russian Baltic Fleet
Togo spread two false stories: one to bait the Russian fleet out of the Baltic, and a second, after it had passed the Cape, that the Japanese were sailing to counterattack — which put the Russians on combat alert for the entire remaining voyage and delivered them exhausted.
Musashi and Togo are both transmitting a state to degrade an enemy's condition before contact, and the pair separates two methods that look identical in effect.
Togo transmits through information. A story is delivered, the Russians reason from it correctly, and the exhaustion follows from competent behaviour on a false premise. The transmission is mediated by belief, and it is defeasible — better intelligence breaks it.
Musashi transmits through presence. No proposition is delivered and nothing false is asserted. The opponent is not reasoning at all; the state arrives the way a yawn arrives.
The insight the pair produces: the second is far harder to defend against precisely because there is nothing to check. A false story can be verified; a mood cannot be fact-checked, and the target has no moment at which they could have caught it, because no claim was ever made. Togo's Russians were wrong about the Japanese fleet's position — an error with a location. Musashi's enemy is not wrong about anything. They have simply become relaxed, which feels like a judgement and is not one.
Sharpest implication. Greene declares Law 10 universal and reversal-proof, and prints the reversal in its own margin. The offensive form does not merely exist — it invalidates the chapter's diagnostic, because the five signs are built to detect someone whose misery is genuine, and a competent transmitter will have a clean record and a stable career precisely because for them it is a tactic rather than a condition. The law protects you from the unwell and leaves you completely open to the skilled.
Generative questions.