The Art of War, Chapter 6: 虛實 (Weak Points and Strong)

The previous chapters in this block cover the decision to fight, the cost of fighting, and the advantage of positions that cannot be beaten. Chapter 6 asks where and when to apply force. Its answer is to take the initiative, concentrate your strength, and strike where the opponent is thin.

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

6.1

原文

孫子曰：凡先處戰地而待敵者佚，後處戰地而趨戰者勞。故善戰者，致人而不致於人。

中文解說

孫子說：凡是先到達戰場等待敵人的，就從容安逸；後到達戰場、倉促投入戰鬥的，就疲勞被動。所以善於作戰的人，能夠調動敵人，而不被敵人調動。

English

The side that reaches the battlefield first and waits is rested. The side that arrives later and rushes into the fight is tired. So a skilled commander moves the opponent and is not moved by the opponent.

致人而不致於人 is the theme of the chapter: hold the initiative and decide the terms.

6.2

原文

能使敵自至者，利之也；能使敵不得至者，害之也。故敵佚能勞之，飽能饑之，安能動之。出其所不趨，趨其所不意。

中文解說

能讓敵人自己趕來，是因為拿利益吸引他；能讓敵人無法前來，是因為製造障礙或威脅。所以敵人安逸，就設法使他疲勞；敵人糧食充足，就設法使他飢餓；敵人安穩不動，就設法迫使他行動。要出現在敵人必須救援的地方，奔向敵人意想不到的地方。

English

An opponent can be made to come forward by offering a gain, and kept away by threatening a loss. If the opponent is rested, tire him. If he is well supplied, starve him. If he is settled, make him move. Appear where he cannot easily respond, and move toward where he does not expect you.

The text gives the commander two levers: incentive and pressure. Both work on the opponent's choices, not only on the battlefield.

6.3

原文

行千里而不勞者，行於無人之地也。攻而必取者，攻其所不守也；守而必固者，守其所不攻也。故善攻者，敵不知其所守；善守者，敵不知其所攻。微乎微乎！至于無形；神乎神乎！至于無聲，故能為敵之司命。

中文解說

行軍千里而不疲勞，是因為走在沒有敵人防備的地方。進攻必定得手，是因為攻擊的是敵人沒有防守的地方；防守必定牢固，是因為守的是敵人不會進攻的地方。所以善於進攻的人，使敵人不知道該守哪裡；善於防守的人，使敵人不知道該攻哪裡。微妙啊微妙，達到看不出形跡；神奇啊神奇，達到聽不到聲響，所以能夠主宰敵人的命運。

English

An army can march a thousand miles without tiring if it travels through country where no one opposes it. An attack succeeds when it hits what is undefended. A defence holds when it covers what will actually be attacked. A skilled attacker leaves the opponent unsure what to defend, and a skilled defender leaves the opponent unsure where to attack. At its best this leaves no visible trace, and the commander then holds the opponent's fate.

This passage is about posture and concealment of intent. Read literally it describes a military advantage in secrecy.

6.4

原文

進而不可禦者，沖其虛也；退而不可追者，速而不可及也。故我欲戰，敵雖高壘深溝，不得不與我戰者，攻其所必救也；我不欲戰，雖畫地而守之，敵不得與我戰者，乖其所之也。

中文解說

進攻而敵人無法抵擋，是因為衝向了他的虛弱之處；撤退而敵人無法追趕，是因為行動迅速，敵人追不上。所以我方想要交戰，敵人即使高築壁壘、深挖戰壕，也不得不出來應戰，是因為我們攻擊的是他必須救援的地方。我方不想交戰，即使只在地上畫條線防守，敵人也無法與我交戰，是因為我們設法讓他改變了目標、摸不著方向。

English

An advance cannot be stopped when it strikes a weak point. A retreat cannot be pursued when it is too fast to catch. If we want a fight, the opponent must come out even behind high walls and deep ditches, because we attack something he has to defend. If we do not want a fight, he cannot engage us even if we only mark a line on the ground, because we have thrown him off his course.

The key phrase is 攻其所必救, to attack what the opponent must rescue. It forces the opponent to react.

6.5

原文

故形人而我無形，則我專而敵分。我專為一，敵分為十，是以十攻其一也，則我衆而敵寡。能以衆擊寡者，則吾之所與戰者，約矣。

中文解說

所以要讓敵人的情況暴露，而我方不露形跡，這樣我方就能集中兵力，敵人卻必須分散。我方集中成一股，敵人分散成十股，就等於用十倍的力量攻擊敵人的一部分，於是我方是多數，敵人是少數。能以多數打擊少數，那麼和我們交戰的對手就很有限了。

English

If the opponent's position is exposed and ours is not, we can concentrate and he must divide. If we are one body and he is split into ten, we attack each part with ten times its strength. We are many where it counts and he is few. Those we actually have to fight are then few.

The advantage comes from information. The side that is better hidden can choose where to concentrate. The numbers are an illustration of the principle, not data.

6.6

原文

吾所與戰之地不可知，不可知，則敵所備者多，敵所備者多，則吾之所與戰者寡矣。故備前則後寡，備後則前寡，備左則右寡，備右則左寡，無所不備，則無所不寡。寡者，備人者也；衆者，使人備己者也。

中文解說

我們要交戰的地點不讓敵人知道，敵人就要防備的地方很多；他防備的地方多，我們實際面對的兵力就少了。防備前方，後方就薄弱；防備後方，前方就薄弱；防備左邊，右邊就薄弱；防備右邊，左邊就薄弱；處處都防備，就處處都薄弱。兵力處於劣勢，是因為要到處防備別人；兵力處於優勢，是因為讓別人到處防備自己。

English

If the opponent cannot know where we will fight, he must guard many places. The more places he guards, the fewer troops he has at any one of them. Guard the front and the rear is thin. Guard the rear and the front is thin. Guard everywhere and you are weak everywhere. The weak side is the one that has to prepare against everyone else, and the strong side is the one that makes others prepare against it.

This is a passage about spreading resources too thin. It applies to the side that is forced to defend everything.

6.7

原文

故知戰之地，知戰之日，則可千里而會戰；不知戰之地，不知戰之日，則左不能救右，右不能救左，前不能救後，後不能救前，而況遠者數十里，近者數里乎！以吾度之，越人之兵雖多，亦奚益於勝敗哉！故曰：勝可擅也。敵雖衆，可使無鬥。

中文解說

所以知道交戰的地點，知道交戰的時間，就是相隔千里也可以趕去會戰；不知道交戰的地點和時間，就會左翼不能救右翼，右翼不能救左翼，前軍不能救後軍，後軍不能救前軍，何況遠的相距數十里，近的也有數里呢！依我的推算，越國的軍隊雖然很多，對勝負又有什麼幫助呢！所以說：勝利是可以爭取到的。敵人雖然人數眾多，也可以使他無法與我們交戰。

English

If you know the place and the day of the battle, you can march a thousand miles to meet it. If you do not, your left cannot help your right, your right cannot help your left, and the front and rear cannot help each other, even when the units are only a few miles apart. By this reckoning, the army of Yue may be large, but it will not help them win. So it is said that victory can be made. Even a large opponent can be kept from fighting.

Two readings are worth noting. The phrase 勝可擅也 is sometimes read as victory 'can be made' and sometimes as victory 'can be seized'. Some editions also record a variant character in this line. The Wikisource text carries a short editorial note there, which is left out of the original above.

6.8

原文

故策之而知得失之計，作之而知動靜之理，形之而知死生之地，角之而知有餘不足之處。故形兵之極，至於無形。無形，則深間不能窺，智者不能謀。因形而措勝於衆，衆不能知。人皆知我所以勝之形，而莫知吾所以制勝之形。故其戰勝不復，而應形於無窮。

中文解說

所以要仔細籌算，以了解敵方計謀的得失；要挑動敵人，以了解他的活動規律；要試探敵人，以了解他所處地形的優劣；要小規模較量，以了解他哪裡有餘、哪裡不足。所以用兵佈陣的最高境界，是沒有固定形跡。沒有形跡，即使深藏的間諜也窺探不到，聰明的人也想不出對策。根據敵情變化而取得勝利，把勝利擺在眾人面前，眾人也看不出其中的奧妙。人們都知道我取勝的表面形態，卻不知道我是怎樣運用這些形態來制勝的。所以每次的勝利都不重複，而應付各種情況的方法是無窮無盡的。

English

Work out the opponent's plan to see its strengths and flaws. Provoke him to learn how he moves. Probe him to learn the ground he stands on. Test him in small clashes to find where he has too much and where too little. The highest form of military posture has no fixed shape. With no shape, the deepest spy cannot see it and the cleverest planner cannot answer it. Victories are won from the opponent's own shape, and the crowd cannot see how. People see the form of our victory, but they do not see how we shaped it. So we do not repeat a victory, and our responses change without limit.

This is the chapter's method: probe first, then commit. It also says that a method which can be copied will be copied, so the response has to change each time.

6.9

原文

夫兵形象水，水之行，避高而趨下；兵之勝，避實而擊虛。水因地而制行，兵因敵而制勝。故兵無成勢，無恒形，能因敵變化而取勝者，謂之神。故五行無常勝，四時無常位，日有短長，月有死生。

中文解說

用兵的形態像水，水的流動是避開高處而流向低處；用兵取勝，是避開敵人的堅實之處而攻擊他的虛弱之處。水依地形決定流向，用兵依敵情決定取勝的方法。所以用兵沒有固定不變的態勢，也沒有永遠不變的形式，能夠根據敵情變化而取勝的，就叫做神妙。所以五行相剋沒有哪一行永遠取勝，四季輪流沒有哪一季固定不動，白天有短有長，月亮有圓有缺。

English

Military shape is like water. Water avoids the high ground and runs to the low. An army avoids what is strong and strikes what is weak. Water takes its course from the land, and an army takes its victory from the opponent. So there is no fixed momentum and no constant form. Whoever can adapt to the opponent and win is called divine. No one of the five elements always prevails, the four seasons do not hold one place, the days grow short and long, and the moon waxes and wanes.

The water image is the best-known part of the chapter. It describes adaptation, not weakness. The closing lines say that no advantage is permanent.

Analysis: what the chapter argues

Initiative is worth more than force. 6.1 and 6.2 argue that the side which arrives first and chooses the ground is rested, and the side that responds is tired. The aim is to move the opponent without being moved. The levers in 6.2 are gain and harm: offer something to draw the opponent in, or threaten something to keep him out.

Find the thin point. 6.3 and 6.4 say that success comes from striking what is undefended and defending what will actually be attacked. 攻其所必救 in 6.4 refines this: attack a point the opponent has to answer, and you can choose the fight. The reverse also holds. Misdirection can let a side avoid a fight it does not want.

Concentrate and the opponent divides. 6.5 and 6.6 turn this into arithmetic. If one side is hidden and concentrated, the other has to spread out. A side that guards everywhere is weak everywhere. The ten-to-one figures illustrate the principle and are not evidence of actual ratios.

Information drives it. In 6.5 the advantage depends on the opponent being exposed while the commander’s own side is not. In 6.7 the side that knows the place and time can cross great distances, and the side that does not cannot even support its own wings. The chapter treats knowing where and when as a form of strength.

Probe before committing. 6.8 gives four tests: reckon the plan, provoke, probe the ground, and make small clashes. Each is a way to learn before spending the main force. Then it says that the best posture has no fixed shape, so there is nothing to copy.

Adapt like water. 6.9 gives the image that most readers remember. Water takes its path from the land, and an army takes its victory from the opponent. The five elements, seasons, days and moon show that strength and advantage change.

Contested points. The close reading of 6.7 is disputed. The phrase 勝可擅也 can be read as victory being makeable or seizable, and some editions note a variant character. Both readings support the same main point. Also, 6.3 and 6.8 praise concealment and misdirection. These are tactics of war, and the next section explains why they cannot be carried over to finance as they stand.

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. This chapter praises concealment, misdirection and deception of the opponent. Nothing below applies that. The reading here is limited to lawful information gathering and sensible posture. It does not mean using material non-public information, insider trading, misrepresentation to counterparties or investors, or any breach of confidentiality or law. Check every use of these ideas against securities law, your firm’s compliance policy and your confidentiality agreements.

Investing

• Be early only where it is lawful and informed. 6.1 says the side that arrives first and waits is rested. In investing, that maps to doing the work before a decision is forced, using public information and permitted research. It does not mean acting on information that is not public.
• Look for where the market is thin, not just where it is cheap. 6.3 and 6.4 favour places that are undefended. By analogy, that can mean neglected segments, illiquid areas, or companies few analysts cover. A thin point may be thin for a good reason, so the work is to find out why.
• Do not spread yourself across everything. 6.6 says that guarding everywhere makes you weak everywhere. A portfolio with too many small positions has little conviction and little time per name. This is an analogy and not a rule on position sizing.
• Test before sizing up. 6.8 probes before committing the main force. A small initial position, a pilot or a staged commitment can be a way to learn before the full amount is at risk, where the mandate and market allow it.
• Do not trust a single method. 6.9 says no advantage lasts. A strategy that worked in one environment can stop working when conditions change or others copy it.

Raising funds

• Choose the ground of the conversation. 6.1 says to move the other side and not be moved. A founder or fund manager who prepares the materials, the data room and the story in advance can set the order and pace of the discussion. That depends on accurate materials.
• Know what the investor must resolve. 攻其所必救 in 6.4 can be read as finding the concern the other side has to settle before it can commit. Answer it directly and early.
• Concentrate the effort. 6.5 favours a united force against a divided one. A raise runs better when a small team owns it, and when the process targets a short list of well-matched investors in place of a wide, unfocused list.
• Probe before the formal process. Early conversations can test the story, the valuation range and the objections, as in 6.8. All statements to investors must be accurate and not misleading.
• Do not copy last round’s playbook. 6.8 says victories are not repeated. Market conditions and investor appetite change from one raise to the next.

M&A

• Understand where the counterparty is stretched. 6.6 describes the side that has to defend everything. A seller or target with several pressures, such as financing, management and a regulatory process, may have little room. Reading this from public information and permitted diligence is ordinary work. Using confidential information improperly is not.
• Work out what the other side cannot give up. 攻其所必救 can be read as identifying the one or two terms the counterparty truly needs. Build the offer around them, and be firm on your own priorities elsewhere.
• Keep your own position steady. 6.5 depends on one side being unexposed. In a process, that means controlling who knows what within the limits of the confidentiality agreement and disclosure rules. It does not mean misleading the counterparty.
• Stay flexible on structure. 6.9 compares good strategy to water. Price, structure, earn-outs, timing and form of consideration can be adjusted to the counterparty’s situation.
• Find the bidder who is spread thin. If a competing bidder is working on several deals, 6.6 suggests it may have less capacity on each. Treat this as an observation, not a plan.

Across all three

• Gather information lawfully and early. The chapter treats knowing where and when as an advantage. Use public sources, permitted diligence and proper expert advice. Do not use inside information or breach confidentiality.
• Pick your point of effort. 6.5 and 6.6 say that effort spread across everything is weak everywhere. Decide which one or two things matter most.
• Probe before you commit. 6.8 reads the opponent through small tests. Prefer reversible steps before large ones.
• Adapt as conditions change. 6.9 says that no form is constant. Review the plan when the facts change.
• Be honest. Position and timing are fair game. Deception of counterparties, investors or regulators is not.

Questions to carry into the next chapter

Chapter 7 (軍爭) moves from choosing the point of attack to the contest for advantage itself, and it argues that the direct route is often not the quickest.

• Where in your current work are you spreading effort across many things when one or two would matter most?
• What small, reversible test could you run before your next large commitment?
• Which part of your approach would stop working if others copied it, and what is your plan for that?