The Art of War, Chapter 9: 行軍 (The Army on the March)

Chapter 8 told the commander to adapt to circumstances and not to follow a fixed rule. Chapter 9 turns to the army in motion. It covers where to camp on four kinds of ground, and then how to read the enemy from what can be seen and heard, since the enemy will not announce his state.

Like every chapter in this series, it has three parts: the reading, an analysis of what the chapter argues, and how finance professionals can interpret it in their own work. The original text follows the Chinese Wikisource edition of 《孫子兵法》. The Chinese and English explanations are Claude’s own paraphrase.

Reading the chapter

9.1

原文

孫子曰：凡處軍相敵，絕山依谷，視生處高，戰隆無登，此處山之軍也。

中文解說

孫子說：凡是安置軍隊、觀察敵情，通過山地時要靠近有水草的山谷，駐紮要選向陽的高處；敵人佔據高地時，不要仰攻。這是在山地行軍作戰的原則。

English

When positioning an army and sizing up the enemy, cross mountains by keeping close to the valleys. Camp on high ground facing the sun. If the enemy already holds the heights, do not climb to attack him. This is how to handle an army in the mountains.

9.2

原文

絕水必遠水，客絕水而來，勿迎之于水內，令半濟而擊之，利；欲戰者，無附于水而迎客，視生處高，無迎水流，此處水上之軍也。

中文解說

渡過河流之後，一定要遠離河岸駐紮。敵人渡水而來，不要在水中迎擊，等他渡到一半時再攻擊，這樣有利。想與敵交戰的話，不要緊靠水邊迎戰，要選向陽的高處，也不要處在敵人的下游迎著水流。這是在河川地帶行軍作戰的原則。

English

After crossing a river, move well away from it. If the enemy crosses toward you, do not meet him in the water. Strike when half his force is across, which favours you. If you want a fight, do not stand at the water's edge to receive him. Hold high ground, and do not position yourself downstream of him. This is how to handle an army by a river.

9.3

原文

絕斥澤，惟亟去無留，若交軍於斥澤之中，必依水草，而背衆樹，此處斥澤之軍也。平陸處易，而右背高，前死後生，此處平陸之軍也。凡此四軍之利，黃帝之所以勝四帝也。

中文解說

穿越鹽鹼沼澤地帶，只管迅速離開，不要停留。如果在沼澤中與敵相遇，一定要靠近水草，背靠樹林。這是在沼澤地行軍作戰的原則。在平原上要選平坦的地方，右邊和後方依靠高地，前低後高。這是在平原行軍作戰的原則。以上四種地形下用兵的好處，正是黃帝戰勝四方諸帝的緣由。

English

Cross salt marsh quickly and do not linger. If battle comes in the marsh, stay near water and grass and keep trees at your back. On flat plains, take level ground, keep high ground to the right and rear, with danger ahead and safety behind. These four rules about ground, the text says, are how the Yellow Emperor defeated four rival emperors.

The Yellow Emperor reference is traditional lore and cannot be checked. The practical content is the four ground rules.

9.4

原文

凡軍好高而惡下，貴陽而賤陰，養生而處實，軍無百疾，是謂必勝。丘陵堤防，必處其陽，而右背之，此兵之利，地之助也。上雨，水沫至，欲涉者，待其定也。

中文解說

軍隊駐紮，喜歡高處，不喜低處；重視向陽，輕視背陰；靠近水草方便給養，駐在地勢堅實之處，這樣軍中沒有各種疾病，就叫做必勝的條件。在丘陵堤防一帶，一定要佔據向陽的一面，並讓它在右後方，這對用兵有利，是地形的幫助。上游下雨，河水泛起泡沫湧來時，想要渡河的話，要等水勢穩定之後。

English

An army prefers high ground to low and sunny ground to shaded. It camps where supplies are plentiful and the ground is firm. Then it avoids disease, and that is what the text calls certain victory. On hills and embankments, take the sunny side with the slope at your right rear. Terrain helps the army in this way. If rain upstream brings foam down the river, wait until the water settles before crossing.

Note the final point. A sign upstream, which you cannot see directly, tells you what is about to happen to you.

9.5

原文

凡地有絕澗，遇天井、天牢、天羅、天陷、天隙，必亟去之，勿近也。吾遠之，敵近之；吾迎之，敵背之。軍旁有險阻、潢井、葭葦、林木、蘙薈者，必謹覆索之，此伏奸之所處也。

中文解說

凡是遇到有深澗阻隔，或是天井（四周高、中間低）、天牢（三面險峻、易進難出）、天羅（草木茂密、難以行動）、天陷（低窪泥濘）、天隙（狹窄溝坑）這類地形，一定要迅速離開，不要靠近。我們遠離這些地方，讓敵人去靠近；我們面對這些地方，讓敵人背靠它。軍隊旁邊若有險要地帶、積水窪地、蘆葦叢、樹林、草木茂盛之處，一定要謹慎地反覆搜索，因為這些都是伏兵和奸細容易藏身的地方。

English

Where there are cliffs, ravines or the five kinds of natural trap (pits, enclosures, thickets, bogs and narrow gaps), leave quickly and do not go near. Keep away from them yourself and let the enemy come near them. Face them yourself and let the enemy have them at his back. If there are rough places, pools, reeds, woods or thick undergrowth near the army, search them carefully, because ambushers and spies hide there.

The terms for the five traps are descriptive labels, and the exact sense of each is a matter of commentary. The main point is clear: avoid places where you cannot see, and search the places where others could hide.

9.6

原文

敵近而靜者，恃其險也；遠而挑戰者，欲人之進也；其所居易者，利也；衆樹動者，來也；衆草多障者，疑也；鳥起者，伏也；獸駭者，覆也；塵高而銳者，車來也；卑而廣者，徒來也；散而條達者，樵采也；少而往來者，營軍也；

中文解說

敵人靠近卻很安靜，是倚仗地形險要；敵人離得遠卻來挑戰，是想引誘我們前進；敵人駐在平坦的地方，是因為那裡對他有利；許多樹木在晃動，是敵人正在前來；草叢中設了許多障蔽，是想使我們疑惑；鳥群驚飛，下面有伏兵；野獸驚逃，是有敵軍突襲；塵土高揚而尖，是戰車開來；塵土低而廣，是步兵開來；塵土散亂而一縷一縷的，是在打柴；塵土稀少而來來往往，是在紮營。

English

If the enemy is close but quiet, he relies on a strong position. If he is far away and provokes you, he wants you to advance. If he camps on easy ground, it benefits him. Moving trees mean he is coming. Many screens in the grass mean he wants you to doubt. Birds rising mean an ambush. Frightened animals mean a surprise attack. Tall, narrow dust means chariots. Low, wide dust means infantry. Scattered, streaky dust means men gathering firewood. Thin dust moving back and forth means a camp is being set up.

This is the start of the chapter's long list of signs. Each is an inference from a physical clue, and several, such as the quiet enemy and the far-off provoker, are about motive and not only about movement.

9.7

原文

辭卑而益備者，進也；辭強而進驅者，退也；輕車先出，居其側者，陣也；無約而請和者，謀也；奔走而陳兵者，期也；半進半退者，誘也；

中文解說

敵方使者言辭謙卑、卻加緊備戰，是準備進攻；言辭強硬、行動上又作勢前進，是準備撤退；輕便戰車先出動、列在側翼，是在布陣；沒有事先約定卻來求和，是有陰謀；士兵奔跑著並排列戰陣，是在期待與我會戰；半進半退，是在引誘我們。

English

If the enemy's envoys speak humbly while his preparations increase, he intends to advance. If they speak aggressively and push forward, he intends to retreat. Light chariots moving out first to the flanks mean he is forming a line. A peace offer with no prior agreement means a plot. Troops running and drawing up in ranks mean a fixed time for battle. A half-advance and half-retreat is bait.

Here words are read against actions. Humble speech with growing preparation, and tough speech with a pull-back, are both cases where the two disagree, and the action is the better guide.

9.8

原文

杖而立者，饑也；汲而先飲者，渴也；見利而不進者，勞也；鳥集者，虛也；夜呼者，恐也；軍擾者，將不重也；旌旗動者，亂也；吏怒者，倦也；粟馬肉食，軍無懸缻，而不返其舍者，窮寇也；諄諄翕翕，徐與人言者，失衆也；數賞者，窘也；數罰者，困也；先暴而後畏其衆者，不精之至也；來委謝者，欲休息也。兵怒而相迎，久而不合，又不相去，必謹察之。

中文解說

士兵拄著兵器站立，是飢餓；打水的人自己先喝，是口渴；見到有利可圖卻不前進，是疲勞；鳥群聚集在營地上，營地是空的；夜裡有人呼喊，是恐懼；軍中紛亂，是將領沒有威信；旌旗搖動不定，是隊伍混亂；軍官易怒，是倦怠；用糧食餵馬、殺牲口吃肉，炊具也不掛起，也不回營房，是走投無路的敵人；低聲下氣、小聲慢慢地對部下說話，是失去了人心；頻頻賞賜，是沒有辦法了；頻頻處罰，是陷入困境；先凶暴而後又畏懼部下的，是最不精明的將領；派人來送禮道歉的，是想休兵息戰。敵軍怒氣沖沖地迎上來，卻久久不交戰，又不撤離，一定要謹慎地觀察。

English

Men leaning on their weapons are hungry. Water-carriers who drink first are thirsty. If he sees an advantage and does not take it, his men are tired. Birds gathering on a camp mean it is empty. Shouting at night means fear. Disorder in camp means the commander lacks authority. Flags that shift about mean disorder. Angry officers mean exhaustion. If horses are fed grain, cattle are slaughtered and the cooking pots are left off the fire, with no return to quarters, the enemy is desperate. A commander who speaks in a low, hesitant way to his men has lost them. Frequent rewards mean he is at the end of his means. Frequent punishments mean he is in distress. One who is harsh first and then fears his own men is the least capable of all. Envoys who come with gifts and apologies want a rest. If the enemy comes forward in anger but neither engages nor leaves for a long time, watch him with great care.

The last sentence is the key. When the signs do not fit a simple story, the text does not guess. It says to keep watching.

9.9

原文

故兵非貴益多也，惟無武進，足以併力、料敵、取人而已。夫惟無慮而易敵者，必擒於人。

中文解說

所以兵力不是越多越好。只要不輕率冒進，能夠集中力量、判斷敵情、爭取人心，就足夠了。只有那些沒有深謀遠慮而又輕視敵人的人，一定會被敵人擒獲。

English

More troops are not always better. Do not advance rashly. It is enough to concentrate your strength, size up the enemy and win over your people. Whoever has no foresight and underestimates the enemy will be captured.

Some editions of the text carry a variant note on the first phrase. That note is editorial and is not part of the passage as quoted here.

9.10

原文

卒未親附而罰之，則不服，不服則難用也。卒已親附而罰不行，則不可用也。故令之以文，齊之以武，是謂必取。令素行以教其民，則民服；令素不行以教其民，則民不服。令素行者，與衆相得也。

中文解說

士兵還沒有親近歸附就處罰他們，他們不會服氣，不服氣就難以指揮。士兵已經親近歸附卻不執行處罰，也無法使用。所以要用恩惠和教化來號令，用軍紀和刑罰來整頓，這叫做必定能得到勝利。平時嚴格執行命令來教導士兵，士兵就會服從；平時不嚴格執行命令，士兵就不會服從。平時命令能夠貫徹的，是因為將領與士兵相處融洽。

English

If you punish soldiers before they feel loyalty to you, they will not submit, and then they are hard to use. If they are loyal and you do not enforce discipline, they are also useless. So command them with care and unify them with firm rules. This is what is called a sure path to winning them over. If orders are consistently carried out in training, the people obey. If they are not, the people do not. When orders are carried out consistently, it is because the commander and the troops are in agreement.

The chapter ends by turning from the enemy's army to one's own. Discipline works only when it is built up in advance, and it rests on trust.

Analysis: what the chapter argues

Ground first. 9.1 to 9.5 give rules for four kinds of terrain: mountain, river, marsh and plain. The common logic is to hold the higher, drier, better-supplied position and to avoid being trapped. 9.4 says that this also keeps the army healthy, so the rules are about condition as well as tactics.

Danger is often hidden. 9.5 names places where an enemy could lie unseen, and tells the army to search them and keep away. The principle is that the risk lies where you cannot see, so you either avoid those places or search them thoroughly.

Small signs, large inferences. 9.6 to 9.8 form a long list of clues and what each suggests. Dust, birds, noise, posture and behaviour are all read as evidence. These are the commentary’s traditional readings, and the chapter does not claim that any single clue is conclusive.

Behaviour over statements. 9.7 sets what the enemy says against what he does. Humble words with growing preparation, or a peace offer with no agreement behind it, are warnings. The action is treated as more reliable than the speech.

Signs of weakness inside the enemy’s camp. In 9.8 hunger, thirst, fear, frequent rewards and frequent punishments show the enemy’s condition. Frequent rewards and punishments point to a commander who has lost control. These are read as symptoms, not as proof.

Some signs are ambiguous. The last line of 9.8 is the clearest case. Where an enemy is angry, close and not fighting, there is no fixed reading, and the text says to keep observing. Several of the other readings are also contested in later commentary, so they should be taken as examples of method and not as a rulebook.

Do not mistake size for strength. 9.9 says more troops are not necessarily better. What counts is concentration, a sound estimate of the enemy and the support of your own people. It warns against underestimating the enemy.

Discipline depends on trust. 9.10 says that punishing before loyalty exists fails, and that loyalty without discipline also fails. The text is clear that orders have to be carried out consistently over time.

A reading note. The chapter’s final lines are about one’s own side. Read in order, the chapter moves from the ground, to the enemy, to oneself. Whether this was intended as a deliberate structure is not something the text states.

How finance professionals can read it

This section is Claude’s interpretation. Sun Tzu wrote about armies, and none of the mappings below are his. The chapter gives a method for inferring a counterparty’s real condition from observable behaviour. In finance, that observation has to stay inside lawful and permitted sources: public filings, published materials, what the counterparty chooses to show, and information obtained through proper channels. Anything that touches material non-public information, confidentiality agreements or market-conduct rules needs a compliance check before it is used.

Investing

• Choose ground before choosing the target. 9.1 to 9.4 prefer the higher, firmer, better-supplied position. By analogy, look at the structure around an investment, such as liquidity, the strength of the balance sheet and how easily you can exit, before the headline thesis.
• Look for the hidden places. 9.5 tells the army to search the areas where others could hide. An analogy is to search the footnotes, related-party items, off-balance-sheet arrangements and contingent liabilities, using public and permitted material.
• Treat signs as circumstantial evidence. The 9.6 list works as a set of clues, none conclusive. Unusual management turnover, a change in auditor, delayed reporting or a sudden change in disclosure style are examples of public signals that may deserve a closer look, and none of them proves anything alone.
• Compare words with actions. 9.7 reads speech against behaviour. A company that talks of strength while it cuts investment, or one that sounds confident while insiders sell in disclosed trades, is showing a gap worth examining.
• Notice frequent rewards and frequent punishments. 9.8 reads these as signs of a commander in difficulty. A loose analogy is repeated restructurings, repeated guidance changes or repeated one-off incentive schemes, which may suggest management is reacting and not steering.
• When signs do not fit, keep watching. The last line of 9.8 gives permission to wait. Not forming a view yet is a legitimate position.

Raising funds

• Read the investor, not only the term sheet. 9.7 compares what is said with what is done. Response time, who attends meetings, how a fund treats diligence requests and whether it moves when it says it will are observable behaviours that can tell a founder more than the stated interest can.
• Beware the unsolicited offer. 9.7 treats a peace offer with no agreement behind it as a possible plot. An approach that arrives unprompted with unusually easy terms deserves the same question: why is this being offered, and what does it want in return?
• Show consistent behaviour to investors. The investors are reading signals from the company as well. Missed updates, late numbers and changes in the story are read as signs of trouble, so consistency in reporting matters.
• Discipline needs trust first. 9.10 applies inward. A company that imposes tight controls before it has built trust with its team may get compliance without commitment. A company with trust and no controls has the opposite problem.

M&A

• Observe the target’s conduct during the process. In 9.7 and 9.8, behaviour shows condition. How quickly a target responds to information requests, how many people are involved, and how consistent its answers are can be read as clues about its state, and should be tested against the documents.
• Check the places where problems hide. 9.5 suggests searching around the army for ambush. In due diligence, this is the equivalent of looking beyond the data room headline into contracts, contingent liabilities, litigation, regulatory exposure and customer concentration, within the scope the agreement allows.
• Watch for bait. The half-advance, half-retreat in 9.7 is a lure. In a negotiation, an apparent concession that comes with a pause or a withdrawal may be positioning and not a change in position.
• Do not equate size with strength. 9.9 warns against thinking more is better. A larger target is not necessarily the stronger fit, and a bigger deal is not necessarily a better one.
• Keep your own side aligned. 9.10 ends on trust and consistent orders. In an integration, the way the buyer treats the target’s staff in the first months sets how much of what is promised later will be believed.
• Legal checks. Information gathered about the target’s staff, customers or competitors needs to be lawful and consistent with confidentiality obligations. If there is doubt, ask counsel before relying on it.

Across all three

• Treat every signal as a hypothesis. The chapter reads dust and birds as evidence, not proof. Write down what a signal suggests, what else would have to be true, and what would disprove it.
• Prefer behaviour to statements. When what someone says and what they do differ, give more weight to what they do.
• Say what you cannot read. The last line of 9.8 allows for a clue that does not resolve. Record it as unresolved and not as a conclusion.
• Stay within lawful sources. Use public and permitted information, respect confidentiality, and check with compliance or counsel when in doubt.

Questions to carry into the next chapter

Chapter 10 (地形) continues with terrain, classifying the types of ground an army faces and showing which failures come from the commander and not from the situation.

• Which current signal about a counterparty are you treating as proof when it is only a clue?
• Where do the words and the actions of a party you are dealing with currently disagree?
• Which hidden place in your current deal have you not yet searched?