The Tenth Chapter: War on a Ship

夫水戰之時，擂一通鼓，吏士皆嚴肅。再擂一通鼓，士伍皆就船，整待〈一作治〉櫓棹；戰士各〈一作為〉持兵器就船，各一〈一作為〉當其所。幢幡鼓角，各〈一作為〉隨所戰船。鼓三通，大小船以次發，左不得右，右不得左，前後不得擅越。違令斬之。

When engaging in naval battle, the first drumbeat is sounded, and all officers and soldiers are to be quiet and on alert. The second drumbeat is sounded, and the soldiers are to board their ships, preparing their oars and paddles (the term '整待' in some editions is '整治'). Warriors are to carry their weapons and board the ships, each taking their proper position (in some editions, it is '各为当其所'). The banners, flags, and drums and horns are also to be assigned according to the ships they are attached to (in some editions, it is '为随所战船'). When the drums have been sounded three times, the large and small ships proceed in order, with those on the left not crossing to the right and those on the right not crossing to the left, and no one is to move out of their proper position. Those who violate the orders are to be executed.

夫步戰之法，擂鼓一通，步騎皆裝。再通，上馬，步皆屯。三通，以次出之。隨幡住〈一作生〉者，結屯住〈一作往〉幡後，聞鼓音整陣，斥候者視之地形廣狹，從四角面立表，制戰陣之宜，諸部曲各〈一作為〉安部陣。兵曹舉曰：不如令者斬之。

The method of marching in battle is as follows: On the first drumbeat, all infantry and cavalry are fully equipped and prepared. On the second drumbeat, the cavalry mount their horses, and the infantry form their camps. On the third drumbeat, they proceed in order. Those who follow the banners and flags (the character '住' in some editions is '生') form their squadrons behind the banners and flags. Upon hearing the drumbeats, they adjust their formations. Scouts are sent out to examine the terrain, and markers are set up at the four corners to plan the battlefield layout. Each unit is assigned its position. The military officer in charge loudly announces that anyone who disobeys the orders will be executed.

若欲結陣，對敵營先立表，乃引兵就表而臨，皆無喧嘩，明聽鼓、看旗幡，麾前則前，麾後則後，左則左麾，右則右麾。不應令而擅前後左右者，斬。伍中有不進者，伍長殺之。伍長不進，什長殺之。什長不進，督兵者殺之。

If you want to form a formation, first set up a marker facing the enemy camp, then lead the troops to line up opposite the marker. No one is allowed to make noise; everyone must listen carefully to the drum and watch the flags. If the flag is waved forward, advance; if it is waved backward, retreat; if it is waved left, move left; if it is waved right, move right. Anyone who disobeys the orders and moves forward, backward, left, or right on their own will be executed. Within a unit of five, if any soldier refuses to advance, the unit leader will kill him. If the unit leader does not advance, the leader of ten will kill him. If the leader of ten does not advance, the officer in charge of supervision will kill him.

督戰之法，將則拔刃在後，察違令不進者即斬之。一步受敵，餘步不進敵者，斬。臨陣兵器弓弩不可離陣，離陣，伍長、什長不舉發者，與同罪。無將軍令而妄行陣間者，斬。臨戰陣，騎兵皆在軍兩頭，前陣叉騎次之，遊騎在後。若步、騎與賊對陣，臨時見地勢便，欲使騎獨進討賊者，聞三鼓音，馳騎從兩翼進戰，視麾所指；聞三金音，即還。此謂獨進戰之時也。步、騎大戰，進退自如法焉。

The method of supervising the battle is: the general draws his sword and places it behind the ranks, observing those who disobey orders and do not advance, and immediately executes them. Some infantry have already engaged the enemy, while others who do not advance to meet the enemy are executed. During the battle, weapons and bows and arrows must not be taken away from the formation; if someone leaves the formation without the officer of the unit or the officer of the ten being reported, they are punished with the same crime. If someone moves around in the formation without the general's order, they are executed. During the battle, cavalry are stationed at both ends of the entire army, with the 'cross cavalry' who move in a cross formation next, and the light cavalry are placed at the end. If infantry and cavalry face the enemy, and they see that the terrain is favorable and want the cavalry to attack alone, they should wait until after three drum beats, then charge from both wings, moving according to the direction of the flag; upon hearing three gongs, they immediately withdraw. This is the time for the cavalry to attack alone. When infantry and cavalry fight together in a major battle, their advance and retreat still follow the above regulations.

臣聞兵者，陰也。陰之德，以虛為用而應於體也。月者，太陰之精氣也。朔望不常，何也？蓋由以虛為變也。兵者既為陰類，則其機宜常虛含變以法月也。能以虛含變應敵，動必利矣。

I have heard that warfare belongs to the category of "Yin." The nature of Yin is to operate through emptiness and spirit, and to manifest in form. The moon is the essence of Taiyin, and its waxing and waning are not fixed, which is why it is so. It is because it changes through emptiness. Since warfare belongs to Yin, the key to military strategy should always maintain emptiness and spirit, and contain change, imitating the moon. If one can respond to enemies with emptiness and change, then any movement will surely be beneficial.

觀乎天文之風雲星辰有吉凶者，天將也。得其吉象不可恃之，恃之者凶；得其凶象不可懼之，懼之者銳。茍不知天象之吉凶者，是虛其機而應天者也。觀乎地理山川險易，有生死存亡之途者，地之利於人也。善用兵者，於地也無生死存亡，觀彼我之勢，察去就之情何如爾，然後乃順其事而用之也。茍不知地理之險易者，是虛其機以應地者也。

Observing the auspicious and inauspicious signs shown by the heavens, winds, clouds, and stars is something that belongs to those with heavenly talent. Obtaining an auspicious sign should not be relied upon, for relying on it may lead to misfortune. Obtaining an inauspicious sign does not necessarily mean fear, for fear only allows the enemy to grow more confident. If one does not rigidly adhere to the auspicious or inauspicious signs of the heavens, this is allowing one's pivot to remain empty and responsive to the heavenly conditions. Observing the terrain's strategic points and ease or difficulty, there are paths of life and death, and paths of survival and destruction, which are the advantages and disadvantages given by the earth. A skilled general does not rigidly determine where life is certain or death is certain in the terrain, but rather considers the situation of both sides, clarifies the actual circumstances of what to abandon and what to take, and then applies it according to the actual situation. If one does not rigidly adhere to the ease or difficulty of the terrain, this is allowing one's pivot to remain empty and responsive to the advantages of the land.

觀乎人事強弱利害有勝敗之勢者，事皆繫於人也。茍以變合於事，強弱利害有勝敗之勢者，事皆繫於人也。茍以變合於事，事合於時，時合於理者，無強弱，無利害，則敗勢可以為勝，勝勢可以為敗也。茍不知人事之勝敗者，是虛其機以應人者也。

Observing the strengths and weaknesses, advantages and disadvantages in human affairs to form a situation of victory or defeat, all of this depends on people. If one can use change to align with circumstances—since the formation of victory or defeat from strengths and weaknesses depends on people; if one can use change to align with circumstances, making things conform to the right timing, and timing conform to reason, then strengths and weaknesses are no longer fixed, advantages and disadvantages are no longer fixed, a losing situation can turn into a winning one, and a winning situation may turn into a losing one. If one does not rigidly cling to temporary victories or defeats in human affairs, this is allowing one's pivot to remain open and responsive to human affairs.

是故善戰者雜於凶而難可釋，雜於吉而難可壯。吉凶交雜而能不惑於用者，此可以上不畏天矣。雜於險而事利，雜於易而事難。險易交雜而能常處其變者，此可以下不畏地矣。雜於〈一作其〉利而敵見其害，雜於害而我敗〈一作馭〉其利。利害雜交而不能屈於敵者，此可以中不畏人也。知此三者而用兵，其盡三才之變乎。自古兵法及臣所著之書，其間申明利害者，蓋以直指其形貌者爾。以臣所謂能審一時之機者，其在天也，無吉凶；其在地也，無險易；其在人也，無利害。

Therefore, the skilled warrior, when facing an ominous situation, does not slacken and cease fighting; when encountering a favorable situation, does not recklessly expand his forces. When good and bad intermingle, he remains undisturbed and continues to wage war as usual, thus not fearing heaven above. When in a perilous situation yet things proceed smoothly, when in a safe situation yet things become difficult; when peril and safety alternate, he remains secure amidst the changes, thus not fearing the earth below. A seemingly advantageous situation may appear beneficial to the enemy but harmful to us; a seemingly disadvantageous situation may be advantageous for us if we can seize the opportunity. When advantage and disadvantage alternate, he does not yield to the enemy, thus not fearing people in the middle. Understanding these three principles and applying them in warfare, one can fully grasp the changes of heaven, earth, and humanity. Since ancient times, military strategies and the writings of this author have discussed advantage and disadvantage, merely pointing out their superficial appearances. The person who can discern the appropriate timing as I have described, finds no good or bad in heaven, no peril or safety in earth, and no advantage or disadvantage in humanity.

用兵之道，先正其禮，次淵其謀，次擇其人。然後詳天地之利害，審人心之去就，行賞罰之公，慎喜怒之理，擇進退之地，張攻伐之權，明成敗之圖，度主客之用。能愛人之生者，可使人舍生而赴死；能親人之身者，可使人捐身而犯難。是故先親於人，俾人然後親之；先勝於敵，就敵然後勝之。

The principles of warfare first require upholding propriety and law, then employing deep and subtle strategies, and then selecting the right people. Then carefully examine the advantages and disadvantages of heaven and earth, investigate the people's support or opposition, implement fair rewards and punishments, be cautious in controlling anger and joy, choose appropriate terrain for advancing and retreating, apply flexible tactics in attack and defense, clearly discern the plans leading to success or failure, and weigh the strategies of both sides. One who values others' lives can make others fight to the death for him; one who cares for others' bodies can make others face danger for him. Therefore, one must first be close to others, and then others will be close to you; first overcome the enemy in calculation, and then truly defeat them in battle.

故用兵必以糧儲為本，謀略為器，強勇為用，鋒刃為備，祿位為誘，斬殺為威；強弱相援，勇怯相間，前後相趨，左右相赴，遠近相取，利鈍相蔽，步騎相承，長短相用〈長兵短兵之用也〉。敵欲堅陣，我則突其不意；敵欲直沖，我則備其所從。攻必先攻其所寡，擊必先擊其所動。薄者可突，長者可截，亂者可惑，疑者可協。

Therefore, in warfare, grain reserves must be the foundation, strategy the tool, strength and courage the combat power, sharp weapons the equipment, official ranks and titles the incentive, and execution of斩杀 as the deterrent. The strong support the weak, the brave complement the timid, the front and rear support each other, the left and right assist each other, the distant and near support each other, the sharp and the blunt protect each other, infantry and cavalry connect with each other, and long and short weapons complement each other. If the enemy intends to hold a position, I attack where he does not expect; if he intends to charge directly, I guard the path he will take. In an attack, I first strike where his forces are weak; in an advance, I first strike where he has just moved. A weak formation can be broken through, a stretched formation can be cut off, a disordered formation can be further confused, and a formation full of doubt can be controlled.

夫軍之為政也，勞在乎役無度，怨在乎賞不均，弱在乎逼迫，窮在乎絕地，離在乎將失道，懼在乎將無勇，饑在乎遠輸，渴在乎窮井。軍之為逸也，樂在乎安靜，利在乎賞罰，當其死在乎軍檢正，成其功在乎戰陣詳。如此者，戰陣之術也。軍之即於戰陣也，從生擊死，從實擊虛，從整擊亂，從利擊害，從逸擊勞，從有餘擊困窮。山陵之戰，不仰高，不速深，不沖隘，不遠追；水上之戰，不違風，不逆流；林中之戰，不連翼，不相馳；草上之戰，不涉深；平陸之戰，不遠離。此戰法之利也。

When governing and leading an army, labor and hardship arise from the lack of restraint in exertion, resentment comes from unfair rewards, weakening of forces results from being forced, being at a loss comes from being trapped in a desperate situation, disunity comes from the commander losing the right path, fear comes from the commander lacking courage, hunger comes from distant supply lines, and thirst comes from dry wells. To ensure the army is at ease, happiness comes from a quiet environment, gain comes from clear rewards and punishments; willingness to die comes from fair inspection within the army, and success comes from well-organized battle formations. These are the techniques of warfare. Once the army is in battle, it should attack from a live position against a dead one, strike at weak points rather than strong ones, attack in order rather than chaos, strike where advantageous rather than disadvantageous, attack when rested rather than fatigued, and attack when strong rather than when weak. In mountain warfare, do not attack from above, do not rashly advance into deep terrain, do not force through narrow passes, and do not pursue defeated troops too far. In water warfare, do not fight against the wind or against the current. In forest warfare, the formation should not be side by side, and horses should not be allowed to run wildly. In grassland warfare, do not enter deep grass. In plain warfare, do not stray too far from the main force. These are the advantages in warfare.

軍之禁也，不節語，言必洩；不峻令，行必亂；不行賞，士必怠。行伍紊亂，由於昧暗〈一作旺〉，在明察以正之。晦夜驚怖，在鎮靜以嚴之。是以知陣之嚴整，軍之表也；軍吏畏愛，將之裡也。軍之所親，將之所在。非智賢，孰能與此乎？

Military taboos include: speaking without restraint leads to the leakage of secrets; lenient commands result in disorder; unfulfilled rewards cause soldiers to become lazy. Disarray in ranks arises from confusion and lack of clarity, which can be corrected by careful observation; panic in the dark must be calmed by calmness and strict order. Therefore, a well-ordered formation is the external aspect of the army; the soldiers' respect and fear towards the general constitute the internal aspect. The place where the soldiers' loyalty lies is where the general is. Only a wise and capable person can achieve this.

諸教戰陣，每五十為隊，從營繕緝搶蟠，教場左右廂各依隊次解幡立隊。伍相去各十步，分佈使均。其駐隊塞空，去前隊二十步。列布訖，諸營士卒一時即向大將麾下聽令。每隔一隊，定〈一作一〉戰隊，即出向前各進五十步。

Whenever a commander trains the troops, each group consists of fifty soldiers. They begin by repairing weapons, preparing supplies, and rolling up banners within the camp. In the left and right sections of the training ground, each group is arranged in order, unfolding their banners and forming ranks. The distance between each group is ten steps, ensuring even distribution. The groups assigned to guard duty fill in the gaps, maintaining a distance of twenty steps from the preceding group. Once the formation is complete, all soldiers from each camp face the general's banner and await orders. Every alternate group is designated as the attacking unit (「定」is also interpreted as 「一」), which then steps forward fifty steps.

聽角聲第一聲絕，諸隊即一時散立；第二聲絕，諸隊一時捺槍、張弓、卷幡、拔刀；第三聲絕，諸隊一時舉槍；第四聲絕，諸隊一時跪膝籠槍坐，目看大將黃旗，耳聽鼓聲。黃旗向前亞，鼓聲動，齊喝“嗚乎”〈並去聲〉，齊向前到中間〈一作界〉，一時齊喝，聲殺齊入。賊退敗訖，可趁行三十步。審知賊徒喪敗，馬軍從背逐北。聞金鉦動，即須聽去行。膊上架槍，側行回身，本處散立。

Listen for the horn signals: When the first horn is blown, each unit immediately disperses and stands in line. When the second horn is blown, each unit simultaneously holds their spears, draw their bows, raise their banners, and draw their swords. When the third horn is blown, each unit raises their spears together. When the fourth horn is blown, each unit kneels, lowers their spears, and sits down, looking at the yellow flag of the general and listening for the drumbeat. When the yellow flag moves forward and the drum sounds, all units shout together "Wuhu" (both syllables are pronounced in the falling tone) and advance forward to the middle between the two armies (in some editions, "middle" is written as "middle boundary"), shouting together at the same time. When the shouting stops, they all charge into battle. After the enemy retreats, they may pursue for thirty paces. Once it is certain that the enemy has been defeated, cavalry will pursue from behind. When the gong is sounded, they must immediately follow orders to retreat and return. They should carry their spears on their shoulders, turn sideways, and return to their original positions to disperse and stand in line.

第一聲絕，一時捺槍便解幡旗；第二聲絕，一時舉槍；第三聲絕，一時旗隊。一看大將處兩旗交，即五隊合為一隊，即是二百五十人為一隊。其隊法及卷幡、舉槍、旗隊、鬥戰法並依前。一看大將處五旗交，即十隊為一隊，即是五百人合為一隊。其隊法及卷幡、舉槍、旗隊、鬥戰法如前。聽第一聲角絕，即散二百五十人為一隊。如此凡三度，即教畢，諸士卒一時聽大將賞罰進止。第三聲角絕，即從頭引隊伍還軍。

After the first horn blast, all the soldiers simultaneously lower their spears and unfold the banners; after the second horn blast, they all raise their spears; after the third horn blast, they all lower the banners and form into a unit. When they see the two banners crossing at the general's position, they combine five units into one, forming a unit of 250 soldiers. The formation method of this unit, as well as the procedures for rolling up the banners, raising the spears, arranging the banners into formation, and engaging in combat, are all carried out as previously explained. When they see five banners crossing at the general's position, they combine ten units into one, forming a unit of 500 soldiers. The formation method and procedures for this unit are the same as before. Upon hearing the first horn blast, they disperse and return to their original formation of 250 soldiers per unit. This drill is repeated three times, after which the drill instructor concludes, and all soldiers wait for the general's orders regarding rewards and punishments and their movements. Upon the third horn blast, they lead the formation back to the camp.

用兵之法，先謀為本。是以欲謀行師，先謀安民；欲謀攻敵，先謀通糧；欲謀疏陣，先謀地利；欲謀勝敵，先謀人和；欲謀守據，先謀儲蓄；欲謀強兵，先謀正其賞罰；欲謀取遠，先謀不失其邇。茍有反是而用兵者，未有不為損利而趨害者也。是故聖王之兵，先務其本，本壯則末亦從而茂矣。茍能知利害之本，謀以禦敵，雖有百萬之眾，可不勞而克矣。

The principle of warfare is based on prior planning. Therefore, if one wishes to plan for military campaigns, one must first plan for the stability of the people; if one wishes to plan for attacking enemies, one must first plan for securing the supply lines; if one wishes to plan for dispersing and arranging troops, one must first plan for occupying favorable terrain; if one wishes to plan for defeating enemies, one must first plan for gaining the people's support; if one wishes to plan for holding strategic positions, one must first plan for accumulating resources; if one wishes to plan for strengthening military forces, one must first plan for establishing proper rewards and punishments; if one wishes to plan for seizing distant lands, one must first plan for not losing nearby areas. Those who act contrary to these principles will inevitably harm themselves and invite disaster. Therefore, wise kings focus first on the fundamentals. When the fundamentals are strong, the rest will naturally flourish. If one can clearly understand the fundamental aspects of advantage and disadvantage and use them to plan for defending against enemies, then even if the enemy has a million troops, one can defeat them without great effort.

孫子曰：勝兵先勝。謂先定必勝之術而後舉也。何謂必勝？許洞曰：先務三和，次務三有餘，次務三必行。何謂三和？曰：和於國，然後可以出軍；和於軍，然後可以出陣；和於陣，然後可以出戰。國不和，則人心離；軍不和，則教令亂；陣不和，則行列不整。不先務此三和之道，何其可戰耶？

The *Art of War* by Sun Tzu, in the chapter *Form*, says: "Victorious armies first achieve victory." This means that armies that are able to win battles always first create conditions that ensure victory before engaging in battle. It means first establishing a certain method of certain victory, and then proceeding to fight. What is certain victory? Xu Dong answered: First, one must achieve the "three harmonies," then the "three surpluses," and finally the "three necessary actions." What are the three harmonies? They are: harmony within the country, then one can go to war; harmony within the army, then one can go into battle; harmony within the formation, then one can engage in combat. If the country is not harmonious, the people's hearts will be scattered; if the army is not harmonious, commands will be confused; if the formation is not harmonious, the ranks will be disordered. Without first achieving these three harmonies, on what basis can one go to war?

何謂三有餘？曰：力有餘，食有餘，義有餘也。力無餘，則困於鬥；食無餘，則怠於時；義無餘，則吏士怨。不務三有餘之術，師其可動耶？何謂三必行？曰：必行其謀，則奸機不成；必行其賞，則好功者不愛死；必行其罰，則有過者不歸咎。不務三必行之道，人其可用耶？

What is meant by the three excesses? It refers to having an excess of military strength, an excess of food supplies, and an excess of righteousness. If military strength is insufficient, the army will be trapped in difficulties during battle; if food supplies are insufficient, it will cause delays and lead to slackness; if righteousness is insufficient, the soldiers and officers will hold grudges. Without the method of the three excesses, how can the army be mobilized? What is meant by the three necessary actions? It refers to ensuring that plans are definitely carried out, so the enemy's schemes cannot succeed; ensuring that rewards are definitely given, so those who seek military merit will not hesitate to risk their lives; ensuring that punishments are definitely enforced, so those who commit mistakes will not shift blame onto others. Without the way of the three necessary actions, how can people be entrusted with responsibilities?

是以知善務和者，公無私，舍小惠務大惠；善務有餘者，力諸事而不自怠；善務必行者，興勇斷，去猶豫之謂也。舉是九者，務令預定之於前，則萬變千機然後動乎其中矣。率此以禦敵，未有不勝者也。故曰：勝兵先勝者，勝在我也。其在《易》曰先天不違之義也。

From this we can see: those who seek harmony are fair and impartial, abandoning small favors in favor of great ones; those who seek abundance strive hard in all matters without being lazy; those who seek to act decisively rise up with courage and resolve, eliminating hesitation. These nine points must be predetermined beforehand, so that in the midst of countless changes and circumstances, one can respond appropriately. By following this approach to resist enemies, there is no failure. Therefore, it is said that an army that wins battles first creates a situation that ensures victory, because the key to victory lies within oneself. This is exactly what the Zhou Changes, the Qian hexagram's Wenyan says: "To act before the heavens do, and the heavens will not contradict."

用兵之術，戰勝不可專，專勝有必敗之理；戰敗不可專，專敗有反勝之道。戰勝而敗者有五：急難定謀狐疑不決，一敗也；機巧萬端失於遲後，二敗也；機事不密，三敗也；似勇非勇，似怯非怯，四敗也；主將不一，五敗也。此五者，皆戰勝而反敗也。戰勝而欲必勝者，定謀貴決，機巧貴速，機事貴密，進退貴審，兵權貴一也。

The art of warfare: after winning a battle, one must not blindly assume victory is certain; within the assumption of certain victory lies the seed of certain defeat. After suffering a defeat, one must not blindly assume defeat is certain; within the assumption of certain defeat lies the path to turning defeat into victory. There are five situations where one could have won but instead ends up losing: first, when in a critical situation one is indecisive and doubtful; second, when there are many opportunities but one hesitates and misses the chance; third, when secrets are not kept confidential; fourth, when one appears brave but is not truly brave, or appears timid but is not truly timid, and thus wavers in advance and retreat; fifth, when the general's orders are not unified. These five points are all cases where one could have won but instead lost. To ensure victory in a favorable situation, one must: make decisions with decisiveness, act with speed in changes of circumstances, keep secrets with strict confidentiality, advance and retreat with caution, and unify military command.

勢敗而反勝者有四：吏士饑渴，割所愛啖之〈割所愛者，謂在急難之中，殺所乘駿馬、愛妾以啖吏士也〉，眾有飽之用矣；吏士恐懼，奮身先之，眾有勇之用矣；期應不到，殺其所暱〈所暱者，謂所嬖倖或子弟諸姻同在軍中，若有主守者犯命則先殺之也〉，眾有懼之用矣；人有疑惑，陰為鬼詐〈鬼詐者，謂詐為狐鳴叢祠中之類也，或假託卜筮，百端不一〉，眾有天之用也〈天謂天所授也〉。如是者，以敗為勝也。勝敗之術，非勇決神智，安能行之耶？

There are four methods to turn a deteriorating situation into a victory: when the soldiers and officers are hungry and thirsty, the general should sacrifice his most cherished possessions to feed them (note: sacrificing cherished things refers to killing his favorite horse or beloved concubine in times of crisis to provide food for the soldiers, thereby giving them the strength of being well-fed); when the soldiers and officers are fearful, the general should lead the charge himself, thus giving them the strength of bravery; if the troops fail to arrive on time as agreed, the general should kill his closest relatives (note: close relatives refer to those he favors or his family members who are in the army. If someone in a defensive position violates military orders, he should be killed first), thus giving them the strength of fear; if the people's hearts are filled with doubts, the general should secretly use deceptive means involving spirits or ghosts (note: deceptive means refer to pretending to make noises like foxes in the forest or sham divination, with many different methods), thus giving them the strength of "heavenly will" (note: heavenly will refers to the will granted by heaven). In this way, a losing situation can be turned into a winning one. Such methods to reverse victory and defeat are not something that ordinary people with mere courage and wisdom can carry out.

敵使來，目數動，色數異而言肆者，刺客也。敵未困而請和者，謀也。敵卑辭厚幣者，驕我也。使雖頻來，為寇不止者，侮我也。厚貨啖我左右者，欲構我密謀也。使來言語辯利，欲兩國休解者，將掩我不備也。使言崛強者，欺我也。敵使有此七者，宜細詳之，將為挾之〈謂謁見之時，以操兵者挾輔而見〉。

An enemy envoy who comes with his eyes constantly moving and his face frequently changing, speaking recklessly, is a assassin. An enemy who has not yet fallen intopredicament but comes to request peace, has another hidden plan. An envoy who speaks humbly and offers rich gifts is trying to make us arrogant. If the envoy keeps coming frequently but does not stop raiding and plundering, it is a show of contempt towards us. If the envoy offers lavish gifts to bribe our close attendants, he is trying to obtain our secret strategies. If the envoy speaks eloquently and claims to desire peace between the two countries, he is preparing to attack us when we are unprepared. If the envoy speaks stubbornly and arrogantly, he is insulting us. If an enemy envoy exhibits these seven behaviors, we should examine them carefully and, when receiving them, have armed guards hold them during the audience.

謀者反其謀〈謂偽許之卻，掩其不備也〉，驕者反其驕〈拒其辭幣使敵人信我為驕也〉，侮者淩之〈舉兵其無禮〉，構者示之〈佯不知，而反示之以虛事也〉，將掩不備復之〈佯聽其說，反掩其不備也〉，欺者誅之〈誅無禮以威敵〉。留使者不可久，久則知我微，不若殺之。是以知奸之道，兵之本也，不可不審。

For those who plot against us, counter their schemes by turning their own plans against them (original note: pretending agreement and then retreating, attacking them when they are unprepared); for those who intend to make us arrogant, let them themselves become arrogant (original note: rejecting their words and gifts, making the enemy believe we are indeed arrogant); for those who insult us, attack them with military force (original note: using their impoliteness as a pretext for military action); for those who attempt to extract secrets, show them false information (original note: pretending ignorance and showing them false matters); for those preparing to attack us when we are unprepared, attack them first (original note: pretending to believe their words, then striking them when they are unprepared); for those who insult us verbally, execute their envoys (original note: executing the disrespectful person to intimidate the enemy). It is not advisable to keep enemy envoys for too long, as they will eventually learn our weaknesses; it is better to kill them. Therefore, the method of uncovering treachery is the fundamental aspect of military strategy, and it must be carefully examined.

敵無恃不可以為寇，欲審者豫審而奪之。敵之為梗，或以強，或以隘，或以勇，或以緩之謂也。奪強以氣，奪隘以動，奪勇以威，奪緩以誘。夫敵以力有餘而加於人，我則以緩伺其力衰而乘之，此奪氣者也。敵以險地壁守，或盈隘而陣，我雖士民豐逸，不可以強取。守者以利暢其心，否則以動則攻之；陣者以勢逼其敵，否則俟動隨而沖之，此奪隘者也。

If an enemy has nothing to rely on, they cannot become a threat, so those who wish to understand the situation should first examine and remove what they rely on. An enemy becomes a problem, either by relying on strong forces, or on difficult terrain, or on brave soldiers, or on being unhurried. To remove their strength, use methods that weaken their morale; to remove their advantage in terrain, use tactics that provoke them into movement; to remove their bravery, use intimidation; and to remove their composure, use enticement. If an enemy uses their superior strength to press against others, I will use a strategy of delaying them until their strength is exhausted, then attack them, which is taking away their spirit. If an enemy fortifies strong positions or blocks narrow passes and sets up defenses, even if our forces are numerous and our people are at ease, we must not attack directly. For an enemy that is holding fast, use rewards to move their hearts, otherwise provoke them into action and then attack; for an enemy that is set in array, use pressure to force them to move, otherwise wait for their movement and then strike suddenly — this is taking away their advantage in terrain.

關塞營壘，糗糧所扼，預於要路伏兵絕之，必力奪其輜重，敵可使饑，此奪緩者也。人逸馬良，恃強輕戰，可據隘設伏，示弱以誘，此奪勇者也。不知四奪，不足以語奇也。兵術萬途，不可專一，先能奪其恃，則彼力衰半矣。

Fortified passes and strongholds are the vital routes for the enemy's supplies and provisions. If you secretly deploy troops along the main roads to cut off these supplies, you must strive to capture the enemy's supplies, thereby starving them. This is called seizing their ease. When the enemy's troops are comfortable and their horses are well-trained, relying on their strength to fight recklessly, you can hold the pass and set an ambush, pretending to be weak to lure them in. This is called seizing their courage. If one does not understand these four methods of 'seizing,' they are not qualified to talk about achieving unexpected victories. The art of warfare has countless strategies; one should not be confined to a single approach. If you can first seize what the enemy relies on, their strength is already reduced by half.

襲虛之術有二焉：一曰因，二曰誘。何謂因？曰：敵兵所向，我亦佯應之；別以精兵潛出虛地，或攻其壘，或斷其後，或焚其積聚也。何謂誘？曰：欲敵之要地則不攻而佯攻其鄰，大其攻具，盛其師旅，以誘敵兵；敵兵到則勿與戰，復於壁守，潛以精銳襲所出兵之城而掩其內。此二者，皆襲虛之道也。

There are two methods for attacking an enemy's weak points: one is called "due" (因), and the other is called "you" (诱). What is "due"? It means that when the enemy's forces are advancing toward a certain direction, our forces pretend to respond to them, while secretly sending elite troops to attack the enemy's weak points, either by attacking their camps, cutting off their retreat, or burning their stored grain and supplies. What is "you"? It means that if we want to attack the enemy's vital area, we do not directly attack it, but instead pretend to attack a nearby city, displaying large siege equipment and a strong military presence to lure the enemy's forces to come to its rescue. Once the enemy arrives, we do not engage in battle, but retreat to our camp and defend ourselves, while secretly sending elite troops to attack the city that sent troops to reinforce, and seize its interior by taking advantage of its weakness. These two methods are both ways of attacking the enemy's weak points.

兵之勝敗，非人之勇怯也。勇者不可必勝，怯者不可必敗，率由勢焉耳。勢之任者有五：一曰乘勢，二曰氣勢，三曰假勢，四曰隨勢，五曰地勢。勢之敗者有三焉：一曰銼勢，二曰支勢，三曰輕勢。

The success or failure in warfare does not depend on the bravery or cowardice of individuals. A brave person does not necessarily win, and a coward does not necessarily lose; it mostly depends on 'the momentum' or 'the situation'. There are five kinds of favorable momentum: first is riding the momentum, second is the momentum of spirit, third is the momentum of deception, fourth is the momentum of following, and fifth is the momentum of terrain. There are three kinds of unfavorable momentum that lead to defeat: first is the momentum of being broken, second is the momentum of being divided, and third is the momentum of being light.

凡新破大敵，將士樂戰，威名隆震，聞者駭懼，回其勢而擊人者，此之謂乘勢者也。將有威德，部伍嚴整，士有餘勇，名譽所加，懾如雷霆，此之謂氣勢者也。士卒寡少，盛其鼓、張其旗為疑兵，使敵人震懼，此之謂假勢者也。因敵疲倦懈怠襲擊之，此之謂隨勢者也。合戰之地，便其干戈，利其步騎，左右前後無有陷隱，此之謂地勢者也。用兵者乘此五勢，未有不能追亡逐敗，以建大功也。

Whenever a strong enemy is just defeated, the soldiers are eager to fight again, the general's reputation is great and his name spreads far and wide, causing fear and awe among those who hear of it. Seizing this momentum to attack others is called taking advantage of the situation. The general has authority and virtue, the troops are well-disciplined, the soldiers still have remaining courage, and the reputation of the army spreads like thunder, causing fear. This is called momentum. When the number of soldiers is small, but drums are beaten loudly and many flags are raised, creating an illusion of a larger force to intimidate the enemy, this is called feigning strength. Attacking the enemy when they are tired and careless is called following the situation. The battlefield is convenient for using weapons, favorable for both infantry and cavalry, and there are no pits or hidden dangers on all sides. This is called terrain advantage. Those who use military force by relying on these five kinds of situations will never fail to pursue and destroy the fleeing enemy and achieve great accomplishments.

又若累戰累敗，吏士畏於戰敵，此之謂挫勢者也〈挫勢者，言曾於敵人控辱，故言勢不利也〉。將無威德，謀慮賞罰不當，吏士之心率多離散，此之謂支勢者也。吏士喧嘩，不循禁令，部伍不肅，此之謂輕勢者也。凡用兵有此三者，未有不敗軍殺將者焉。

If a force keeps losing battles repeatedly and the military officers and soldiers are afraid to fight the enemy, this is called a broken momentum. The main general lacks prestige and virtue, his strategies are incomplete, his rewards and punishments are improper, and the military officers and soldiers are mostly disunited and scattered, this is called a divided momentum. The military officers and soldiers are noisy and disorderly, they do not follow the prohibitions, and the ranks are not properly disciplined, this is called a light momentum. Whenever a military campaign has these three situations, there will surely be losses of soldiers and generals.

是故乘〈一作五〉勢在我，可以指揮進攻矣；任〈一作五〉勢在敵，我當有道，反能擊之。若夫敵有乘勢而到者，未可與戰，堅壁固守，待之曠日持久，敵心必緩於始到矣；俟其攻無所拔，掠無所得，敵之眾心益以慢矣；當於中夜潛令驍勇襲其營壘，攻其無備，乘其亂出精兵兩道擊之〈地勢便則兩道出，不便則一道出〉，壁中鼓譟應之。如此，則可以破其敵者矣。

Therefore, if the momentum is on our side ("cheng" is sometimes written as "wu"), we can freely take the initiative in launching an attack; if the momentum is on the enemy's side ("ren" is sometimes written as "wu"), we should still have a way to counterattack. If the enemy is advancing with strong momentum, we should not engage them directly but instead fortify our defenses and endure the conflict over a long period, wearing down their morale. As time passes, their initial vigor will inevitably wane. When they find themselves unable to attack or plunder, the enemy's troops will become even more careless. At this point, we should secretly send brave and capable soldiers to attack their camp at night, striking at their unguarded points. When they are in confusion, we should send elite troops to attack from two directions (note: if the terrain is favorable, attack from two directions; if not, attack from one direction), with the camp's forces beating drums and shouting to support them. In this way, we can defeat the enemy.

敵有恃氣勢而到者，可以後潛精兵，偽示以老弱；敵進攻則發伏擊之，必勝矣。何謂也？許洞曰：精勢在人者，止用勇敢疾速為務，鮮能精謀慮。彼見老弱，必輕進轢〈一作揲〉陵之，堅陣以俟，一鼓不勝，鋒必挫，反為我乘矣。

If the enemy comes relying on their momentum, we should hide our elite troops behind and deliberately send the elderly and weak soldiers to the front. When the enemy attacks, we launch our ambush to strike them, and we will certainly win. Why is this so? Xu Dong answered: Those who are strong in momentum are always focused on bravery and speed, and rarely plan carefully. When they see our side full of the old and weak, they will certainly rush forward recklessly, wanting to crush and dominate us. If we form a solid formation to wait for them, they will be unable to break through in one attack, and their momentum will be weakened. Then we can take advantage of the situation to strike them.

敵有以假勢而到，旗鼓之盛，埃芇之多矣〈旗鼓或露眾芇或以曳戰〉。預料敵國兵：如國有十萬之眾，侵伐之地不及五萬之師矣，降之不溢三萬矣；國有百萬之眾，侵伐之地不及五十萬之師矣，降之不溢三十萬〈謂其各有屯授之地及死亡之所，或徵兵不能盡到侵伐之地〉。以此料之，百萬之國，其眾來者有百萬、六十、七十、八十、九十萬之旗鼓與號令者，必不溢四十萬矣，餘皆疑兵也；十萬之國，其眾來者有四萬、五萬之旗鼓與號令者，此必不溢三萬矣，餘皆疑兵也〈敵國大小、敵眾多寡，皆以此類數知之也〉。

If the enemy comes with false strength, displaying a great number of banners and drums and raising a lot of dust, one can estimate the enemy's actual forces in advance. If a country has an army of a hundred thousand, the actual number of troops deployed to the front lines of invasion is less than fifty thousand, and after further reduction, will not exceed thirty thousand. If a country has a million troops, the actual number deployed to the front lines is less than fifty thousand, and after further reduction, will not exceed thirty thousand (note: this refers to the fact that they have garrisons and losses in different areas, or that not all troops can be mobilized to the front). According to this estimation, if an army from a country with a million troops arrives, even if it displays banners and drums of a hundred thousand, sixty thousand, seventy thousand, eighty thousand, or ninety thousand, the actual number will certainly not exceed forty thousand, the rest being decoys. Similarly, if an army from a country with ten thousand troops arrives, even if it displays banners and drums of four thousand or five thousand, the actual number will certainly not exceed three thousand, the rest also being decoys (note: the size of the enemy country and the number of enemy troops can be estimated in this way).

是以知旗鼓多者，其兵少矣，不可怖。但以精兵出其不意，必敗矣。或敵探我動靜者，為我所知，即詐示以疲倦懈怠，使知之。敵必隨勢而來，預於諸間道及通衢陰伏銳兵俟之〈先令細人密探敵人舉兵之期，然後設伏以待，亦可〉，過半則邀擊之。敵得地勢以薄我，未可與戰，堅壁觀之，持久則眾心怠。

From this we can see that the more flags and drums are set up, the fewer soldiers there actually are, so there is no need to be afraid. As long as we use a select force to attack unexpectedly, the enemy will certainly be defeated. Sometimes when the enemy comes to spy on our movements, if we become aware of it, we should deliberately appear tired and careless, allowing them to continue their reconnaissance. The enemy will certainly follow this trend and advance toward us. We should then secretly position our elite troops along all the small paths and main roads in advance. When the enemy has advanced halfway, we should attack them from the flank. If the enemy occupies advantageous ground and approaches us, we must not engage them in battle. Instead, we should fortify our position and observe, waiting for the enemy's morale to gradually weaken.

夫得敵有銼勢者，可以自外擊之；敵有支勢者，可以自內擊之〈內攻為用間得其敵心，然後擊之也〉；敵有輕勢者，可以突之〈掩不備也〉。此隨敵三敗勢攻之也。以此言之，是故多勝者非強也，多敗者非弱也，率由勢爾。夫水之柔弱，方圓任性而能蹶〈一作寢〉堤漂石者，水之勢也；火之剛〈一作測〉炎，亙天而起者，火之勢也；薪木既灰而滅影者，木之勢也。故用兵之道，既知水火之旺敗，則盡於勢之用矣。

When an enemy is in a state of decline, you can attack him from outside; when he is in a state of division, you can undermine him from within (original note: undermining from within means first using spies to win over the enemy's people, then attacking); when he is in a state of weakness, you can attack him directly (original note: take advantage of his lack of defense). This is following the enemy's three forms of decline to attack him. Therefore, those who win many battles are not necessarily strong, and those who lose many battles are not necessarily weak; it all depends on "the situation" or "the momentum." Water is originally soft and weak, but it can take the shape of a square or a circle, yet it can break dikes and float away stones ("jue" is sometimes written as "qin"), which is the momentum of water; fire is originally fierce and strong ("gang" is sometimes written as "ce"), but it can rise to the sky, which is the momentum of fire; firewood, once burned to ashes, leaves no trace, which is the momentum of wood. Therefore, the principles of warfare, once you understand the rise and fall of water and fire, you have fully grasped the use of "the situation" or "the momentum."

《周禮》巡國傳謀，反間也。用間之道，聖人以用兵決勝，不可不間。用間決中，不可不密。茍非大智，孰能臻於是乎？故間之行也，觀事而舉，其術有八焉。其一曰：兩國相拒，兵抗其境，詐為疲困畏懼，潛漏其言，厚貨諂敵所愛幸，因以所求中之；次使使者致玉帛子女與駿馬精佩之飾以求和解；覺其驕慢，陰選精兵分道，早夜兼時，以乘不備，此以使者為間者也。

The duties mentioned in the "Rites of Zhou" of touring various states and conveying strategies are referred to as reverse espionage. The principle of using spies is that a sage in warfare must decide victory, and thus cannot do without spies; employing spies requires striking at the vital points, and thus cannot afford to keep secrets. Without extraordinary wisdom, who could reach such a level? Therefore, the implementation of espionage depends on the situation, and there are eight methods. The first method is when two countries are in a stalemate, with armies facing each other at the borders. Our side pretends to be weary and fearful, secretly leaking this information to the enemy. We then offer heavy rewards and gifts to the enemy's favored individuals, using them to please the enemy. Then we send envoys with jade, silk, beautiful women, swift horses, and fine ornaments to request peace. Once we detect the enemy's arrogance and negligence, we secretly select elite troops to launch attacks from different routes, moving day and night to strike when they are unprepared. This method uses the envoy as a spy.

其二曰：獲敵生口，以所謀漏〈一作洩〉之〈謀皆虛者，非實也〉，俾得聞焉，陰緩使遁去，令敵得所謀而信之，我行則不然也，此以敵人為間者也。其三曰：敵來間，我詐為不知也，反事示之，敵將為事，我則出不意而擊之，此反求來言以為間也。其四曰：敵以間來，厚賂之，令反其言以間敵，此反以來人為間也。

The second type: capturing an enemy spy, deliberately leaking false information about our plans to him, letting him hear it, then secretly relaxing his guard to let him escape back, so that the enemy obtains this 'plan' and believes it to be true, while our actual actions are different—this is using the enemy's person as an agent. The third type: when the enemy sends a spy, we pretend not to know, and instead show him false appearances. Based on this, the enemy takes action, and we strike unexpectedly—this is using the spy's message in reverse to carry out espionage. The fourth type: when the enemy sends a spy, we bribe him heavily, and have him return with false information to deceive the enemy—this is turning the incoming person into our own agent.

其五曰：與敵人戰，佯為小敗，亟引兵深壁示以懼色，乃選語言鄙鈍、無智慮者使於敵，令盛張皇我軍之強盛，俾敵知為間者，必以我為懼，以強詞來間也；既行，即舉奇兵隨而襲擊之，此以明間而為間者也。其六曰：敵有內寵，令心腹者以金寶饋其家，使潛構敵情，此以內嬖為間者也。

The fifth method: when fighting against the enemy, pretend to suffer a minor defeat, quickly retreat into a strong defensive position, and deliberately show signs of fear. Then send a person who speaks coarsely and has no cunning to the enemy's camp, letting him spread the word that our army is very powerful. This will make the enemy realize that he is an agent sent by us. The enemy will then believe that we are afraid and are using such exaggerated words to deceive them. Once the messenger leaves, our forces should immediately launch a surprise attack on the enemy — this is using an open spy to carry out espionage. The sixth method: if the enemy's ruler has a favored court official, send a trusted person to deliver gold and jewels to his home, so that he can secretly obtain information about the enemy — this is using the favored court official as a spy.

其七曰：敵有謀臣，則潛行賂敵親信，構讒於內，外以事應讒者言，使君臣相疑，自相殘害，此以讒人為間也。其八曰：求敵所委信者，副其所欲，陰求其動靜言語者，此以鄉人為間者也。是以知間者，兵家之要妙也。茍非賢智，莫能用之。故用間之道，在乎微密潛誠，此良將之所註意也。

The seventh type: if the enemy has a trusted and capable minister, one should secretly bribe the enemy's close confidants to spread slander within, and create incidents outside to confirm the slanderer's words, causing the enemy's king and ministers to suspect each other and turn on one another—this is using the slanderer as an agent. The eighth type: identify the person the enemy trusts and relies on, flatter his desires, and secretly investigate his movements and conversations—this is using a local acquaintance as an agent. From this, we can see that agents are the most crucial and subtle aspect of military strategy. Without a wise and intelligent person, one cannot effectively use agents. Therefore, the principle of using agents lies in being subtle, meticulous, secretive, and sincere. This is something a good general must pay particular attention to.

守備不可不講。善守者如環，使敵不得其間而入焉。夫人之治身者，血脈往來通暢於四肢，則安寧矣。或一脈不來，一氣不通，未有免於病者。是以善用兵者，雖四屯急難，則如首尾相顧而不窮，斯為妙矣。

Defensive strategies must be carefully considered. A skilled defender arranges his defenses like a circular ring, with the beginning and end connected, so that the enemy cannot find any opening to attack. When a person maintains his body properly, the blood flows smoothly to the limbs, and the body remains healthy. If there is a place where the pulse does not reach or the energy flow is blocked, illness is inevitable. Therefore, a skilled general, even when all the surrounding troops are under attack at the same time, can respond effectively like the snake of Changshan, with the head and tail supporting each other, without being overwhelmed. This is considered truly skillful.

敵人信鬼多祈禱者，必懷疑懼，不能任人故也，一可擊也。敵惟務天時，擇其方位，觀其雲氣，不顧地形之險易，不詳人心之逆順，二可擊也。敵止以地利為擇，不能整肅號令，嚴戒行伍，三可擊也。結營分陣，時多動移者，此多疑恐，四可擊也。軍發言無誠實，事多利己，吏士怨怒，五可擊也。

An enemy who is superstitious and frequently prays is surely troubled and fearful, because he does not trust his subordinates. This is the first situation in which we can attack. An enemy who only focuses on auspicious times, selects positions, observes clouds, but ignores the terrain's difficulties and does not carefully examine the people's loyalty or opposition, this is the second situation in which we can attack. An enemy who only knows how to choose favorable terrain but cannot maintain strict commands and discipline within the ranks, this is the third situation in which we can attack. After setting up camps and forming divisions, if an enemy frequently changes positions, it shows he is very doubtful and fearful, this is the fourth situation in which we can attack. If the army's orders are not trustworthy and the commander often acts for his own benefit, causing the officers and soldiers to be resentful and angry, this is the fifth situation in which we can attack.

將吏淫怠，六可擊也。結營之地，四要無防〈四要者，四面間道也〉，七可擊也。將馭人無禮，八可擊也。賞罰顛倒，九可擊也。將士多輕，十可擊也。茍欲擊之，先令細人密構其實而我乘之，然後行擊，必中矣。我師亦宜以此自為戒焉。

When the enemy's officers indulge in pleasures and neglect their military duties, this is the sixth situation in which we may attack. If the enemy's camp is unguarded on all four sides (the original note refers to the four minor roads around the camp), this is the seventh situation in which we may attack. If the commander fails to treat his subordinates with proper courtesy, this is the eighth situation in which we may attack. If rewards and punishments are reversed and confused, this is the ninth situation in which we may attack. If the soldiers are mostly reckless and impetuous, this is the tenth situation in which we may attack. If we wish to attack, we should first send spies to secretly investigate these conditions. Then, based on the information obtained, we should take advantage of the enemy's weakness and strike, ensuring we hit the vital point. Our own army should also use these ten points as a warning for self-discipline.