Section 44: Assessing the Enemy's Camp

敵營糧道不通利者，可守之。敵營得高燥之地而不顧泉水之利者，可俟之；俟之久，則人馬多渴也。敵營得泉水之利而地勢下濕者，可逼之。敵營地勢不順出入者，可攻之。敵營寬大而兵少者，可薄之。敵營圍密而兵寬者，不可輕之。敵營四周守備不均者，隨其虛處以攻之。敵營前後左右有出入之便者、水草之利者，不可輕之。此皆料陣法也。

If the enemy's supply lines are not smooth, they can be surrounded and held in a stalemate. If the enemy occupies a high, dry area but neglects the convenience of water supply, we can wait them out; over time, their troops will become thirsty. If the enemy has access to a spring but the terrain is low and damp, we can attack closely. If the enemy's terrain makes it difficult for them to move in and out, we can attack. If the enemy's camp is large but their forces are weak, we can attack closely. If the enemy's defenses are tightly arranged but they still have sufficient strength, we must not look down on them. If the enemy's defenses are uneven around them, we should attack where they are weak. If the enemy has easy access in all directions and also benefits from water and grass, we must not look down on them. These are methods for assessing the enemy's camp.

望氣者以氣勝敗告於大將。觀敵之氣衰則進攻，氣旺則止兵勿與戰，此之謂順天時者。彼之氣旺，他人皆懼怯不敢進兵，我獨勇而進焉，反能必勝者，何也？在乎以智逆於氣，而己順任乎時者也。夫五行之旺，以日、時為用。靜為主，動為客。

Military diviners who practiced "looking at the qi of clouds" would report to the general the signs of victory or defeat shown by the clouds. When the enemy's qi appeared weak, they would attack; when it appeared strong, they would hold back and not engage, which is called following the heavenly timing. However, if the enemy's qi is strong and others are afraid to advance, yet I alone charge forward and can surely win, why is that? The key lies in using strategy to act against the clouds' indications, while still following the generation and overcoming relationships of the day branch and hour. The prosperity and strength of the Five Phases are calculated based on the day branch and hour; the one that remains still is called "the main," and the one that moves is called "the guest."

敵上勝氣有如門上樓如杵如枝，或曰赤為木，我則俟金時，自西擊之，可克矣；水日水時不可也，水能生木故也。敵上勝氣或赤如火光火煙之狀，暈暈而起者，木日木時不可也，為木能生火也；日為火，亦俟水時自北擊之，可克矣。

The enemy's aerial energy is strong, appearing like a pavilion on a door, like a wooden mallet, or like branches. Its color belongs to wood (the original text says 'red,' which should be 'blue'). Our side should wait until the hour of metal and attack from the western metal position, thus controlling it. Do not attack on days or hours of water, because water nourishes wood, which would instead strengthen the enemy's energy. If the enemy's aerial energy appears red like firelight or smoke, rising in waves, it belongs to fire. Do not attack on days or hours of wood, because wood nourishes fire. Since this energy belongs to fire, wait until the hour of water and attack from the northern water position, thus controlling it.

敵上勝氣如白粉者，白為金，水日金時皆不可也；茍金日火時，利自南方攻之，可克矣。敵上勝氣黃如土臺者，土日金時不可也，金日土時不可也，金日金時、土日土時皆不可也；土日木時，利自東擊之。黃者土也，臺者亦土也。不言雲氣如水狀而及色黑者，緣黑氣多為敗氣，此不復用。

The strong energy in the enemy's sky appears white, like powdered chalk. White belongs to metal, so do not use troops on days or hours belonging to metal. If it is a day of metal and an hour of fire, it is advantageous to attack from the southern fire position, as fire can overcome metal. The strong energy in the enemy's sky appears yellow, shaped like a platform. This belongs to earth. On days of earth, pairing with hours of metal is not suitable; on days of metal, pairing with hours of earth is not suitable. Pairing days of metal with hours of metal, or days of earth with hours of earth, is also unsuitable. Instead, on days of earth, pairing with hours of wood is advantageous, and attacking from the eastern wood position is favorable. Yellow is earth, and the platform shape also belongs to earth. We do not discuss clouds that appear like water and are black in color, because black clouds are mostly signs of defeat and are not used.

或敵人先據吉地，我之頓軍稅駕，逼近於凶神死氣之上，不得利門而出者，但觀我軍上雲氣及敵上雲氣形與色，以五行相生相剋用之。敵氣能生我，我則出師進戰；我軍上氣能克敵，亦利出師進戰。不然，則勒兵撫士，戒嚴警備，俟時而動焉，不可妄也。夫天下專勝敗之氣，由人用之而已。兵家萬變，此其一也。

Sometimes the enemy occupies a favorable location first, while our army's encampment and unloading area is close to the position of death qi. If there is no favorable direction to launch an attack, we should observe the shape and color of the clouds above both our troops and the enemy. Using the principles of mutual generation and mutual control among the five phases, we can determine our course of action. If the enemy's qi can generate our qi, we should launch an attack. If the qi above our troops can control the enemy's qi, it is also favorable for an attack. If neither of these conditions is met, we should整顿 our troops, comfort our soldiers, maintain strict vigilance, and wait for the right opportunity before taking action, without acting rashly. The clouds that determine victory and defeat in the world are ultimately just tools to be used by people. The strategies of military affairs have countless variations, and observing the clouds is just one of them.

兵法曰：“散地無戰。”散地者，境內地上也，士卒顧家，其意未專，不可戰也。“輕地則止。”入敵地尚淺，士卒意未堅，不可以進敵，當自堅其心也。“爭地則無攻。”山谷隘險之口，以弱勝強，以少擊眾之地也。“交地則無絕。”俱可進退之地，不可以兵絕之。“衢地則合交。”有路往來，我可結交於諸侯也。

The Art of War by Sun Tzu, in the chapter on Jiudi, says: "Do not fight in a scattered territory." Scattered territory refers to a battlefield within one's own country, where soldiers are preoccupied with their families and lack focused determination, so it is not suitable for a decisive battle. It also says: "Do not advance hastily in a light territory." When entering enemy territory but not deeply, soldiers' resolve is not yet firm, so one should not rush to advance but first stabilize the morale of the army. It further states: "Do not attack in a contested territory." Contested territory refers to narrow mountain passes or valleys, which are places where the weak can overcome the strong and the few can defeat the many; if the enemy has already occupied such a place, do not attempt to attack forcefully. It also says: "Do not cut off in a crossroads territory." Crossroads territory is an area where both sides can move freely, so it is not advisable to send troops to block it. Lastly, it says: "In a thoroughfare territory, form alliances." Thoroughfare territory is a place that is well-connected and accessible, where one's side can establish alliances with other states.

“重地則掠。”深入敵境，士卒意已堅固，可以掠取財物。“圍地則謀。”士卒因於險隘，鬥則兵弱，持久則糧食乏絕，則當用謀以免難。“死地則戰。”前有高山，後有大水，糧食乏絕，進退守備皆無所利，當則曰死戰也。許洞曰：此八者，古人用戰地之法。若地協於用則用之，不協於用則反之。

It is also said: "In a heavily fortified area, one should plunder." When deep within enemy territory and the soldiers' resolve is firm, they can gather supplies and resources locally to support the army. It is also said: "In an encircled area, one should plan." When soldiers are trapped in a narrow pass, fighting directly would mean inferior numbers, while prolonged engagement would lead to the exhaustion of supplies. In such a situation, one should use strategies to escape困境. It is also said: "In a dead area, one must fight." When there is a high mountain ahead and a great river behind, with supplies cut off, there is no advantage in advancing, retreating, or holding ground. In such a case, one can only fight to the death. Xu Dong said: the above eight points are the methods used by ancients to utilize terrain. If the terrain matches the method, it should be used accordingly; if not, it should be used in reverse.

反之之謂何也？曰：若敵眾深入吾境，營壁不完，芻糧寡少，守且不利，詎可以散地而不戰乎？在我當以必戰為約，怯退示以必死，擒獲示以必賞。令立告諸吏士：將戰之際，後顧斬之，臨敵而目不定、目數移者斬之，有憂色者斬之，偃蹇者斬之，相視而動目者斬之，遺弓刀器械者斬之，金鼓不應節者斬之；獲一首級者亦厚賞之。如是，則有散地之用矣。

What does it mean to use the reverse method? The answer is: Suppose the enemy launches a large-scale invasion into our territory, and our defenses are not secure, with insufficient fodder and grain, making it difficult even to hold our ground. Can we refrain from fighting just because it is a "disadvantageous position"? At this time, our side should adopt a resolute stance to fight, and make a clear agreement: anyone who shows cowardice and retreats will be executed, and anyone who captures an enemy will be heavily rewarded. The military orders should be clearly communicated to all soldiers in advance: during battle, anyone who looks back will be beheaded; anyone who faces the enemy with wavering eyes and frequent glances will be beheaded; anyone who shows signs of fear will be beheaded; anyone who is arrogant and does not obey orders will be beheaded; anyone who looks at each other and signals with eye contact will be beheaded; anyone who discards bows, swords, and weapons will be beheaded; anyone who sounds the gongs and drums out of rhythm will be beheaded; and anyone who captures a head will be heavily rewarded. In this way, even a disadvantageous position can be made useful.

入敵地尚淺，險則據而挑，夷則守而應。慮士卒心不固，當擇左右前後背險絕面夷生路，肅部伍，嚴節制，使人人有自戰，是則有輕地之用矣。

When entering an enemy's territory but not deeply, if the terrain is difficult, occupy the dangerous positions and challenge the enemy; if the terrain is flat, hold the position and wait for the enemy to attack. If worried about the soldiers' morale being unstable, select a place where the troops are flanked by dangerous terrain on all sides, with flat ground in front, to set up the army. Organize the troops, enforce strict discipline, and assign each person a specific position and responsibility to fight. In this way, the advantage of a light position also becomes useful.

山谷險隘，敵人先得以控隘我勢，我當屯師為大營廣陣，務攻其懈。其機狀如不密，俾敵見之，則洩謀矣。欲敵人備在前，陰出精銳敢死者循間道，或扼其糧運，或搗絕其後。凡間道必多險阻，或有巖崖峭壁之地，則為懸梯竹索以陟登之；或有深淵澗，則為罌缶渡之。覺敵內撓，則自營陣中出精兵為應，內外夾攻，有爭地之用矣。

In mountainous and dangerous passes where the enemy has already occupied the pass to control our situation, we should station a large army and form a large camp with a wide formation, waiting for the enemy to become careless before attacking. If such strategies are not carried out meticulously, the enemy will discover our plans and our tactics will be exposed. We should make the enemy place all their defenses in the front, while secretly sending elite and fearless soldiers to move along narrow paths, either cutting off their supply lines or directly attacking and cutting off their rear. All narrow paths are sure to have many obstacles: if there are cliffs and steep rocks, we use hanging ladders and bamboo ropes to climb up; if there are deep ravines and streams, we use "yongfou" (large-mouthed clay jars tied together as floating devices) to cross. Once we detect that the enemy's internal order has been disrupted, we should send elite troops from our main camp to support the attack, launching an attack from both inside and outside. In this way, the use of strategic positions becomes evident.

道路相錯，我可以往，彼可以來，利設伏進戰，戰佯敗，俟逐兵過半則舉號發伏沖擊之，反佯敗之師以應，有交地之用矣。

The roads are intersecting and crisscrossing, allowing both our forces and the enemy to pass through; such a place is favorable for first setting an ambush and then engaging in battle. When fighting, pretend to retreat, and when the enemy has pursued half of their forces, raise the signal to launch the ambush troops to attack. At the same time, have the previously pretended retreating troops turn back to encircle and support. In this way, the terrain of intersecting paths can be effectively utilized.

頓泊之地逕達四面，當選腹心勁勇者各將步、騎以扼四沖，人數隨多少使之，雖無交應，有衢地之用矣。

The location where the army is stationed has roads leading in all four directions. In this case, one should select trusted and strong soldiers to command infantry and cavalry, each taking charge of key strategic points in the four directions. The number of troops should be adjusted according to the situation. In this way, even if it is impossible to communicate and coordinate with the feudal lords, the strategic advantage of a crossroads location still remains useful.

致兵敵境，凡屬守備者，順利安之，否則夷之。資食所獲，必副吏士，內以悅師人，外絕敵所恃。豈直深入然後用掠乎？如是，則用掠非止重地之用矣。

When the army advances into enemy territory, all enemy strongholds should be dealt with: those that submit should be pacified, and those that do not should be destroyed. The captured supplies and food must be distributed to the soldiers. Internally, this delights the troops, and externally, it cuts off the enemy's reliance. Why must one wait until deep inside enemy territory to engage in local plundering? Therefore, the principle of 'plunder' is not limited to situations involving important strategic locations.

大兵將動，先料其強弱，觀其云勢，察地勢逆順，審人心向背，而後舉焉。兵法曰：策之而知得失之計，候之而知動靜之理。故得失之道，利在先知。謀勝於未勝，慎於未失者，善也。有死地之危，始謀於軍者，必有後機之困矣。設能反後機而達先知，必無圍地之患矣。

A large army about to move must first assess the strength of both sides, observe the formation of clouds, examine the terrain's advantages and disadvantages, and evaluate the people's support before taking action. The "Art of War" by Sun Tzu says: calculating the enemy's situation allows one to understand the balance of gains and losses, and investigating the enemy's movements allows one to grasp the patterns of activity and inactivity. Therefore, the key to success lies in knowing beforehand. Planning to win before actually winning, and being cautious before any mistake occurs, is called wisdom. If one only begins to plan when already in a desperate situation, they will certainly suffer the consequences of being out of step with the right moment. If one can overcome the disadvantage of being behind the timing and achieve foresight, then they will certainly avoid the disaster of being surrounded.

高山大澤，險阻峭壁，沮洳溪逕，斷絕無以生遁，此乃智士用謀之利也。當宜用奇兵出不意，以沖寇敵而後擊之。出奇奔沖，或利用燧馬、燧牛如田單、陽班之類是也；或候夜昏詐為號，直奔沖敵師，混服飾軍伍，使不辯認之類是也。如止以死戰為期，茍敵兵益壯，我援不利，則李陵有弓折矢盡之困矣。戰極力斃，當自殞陷。能竭智用謀，萬變不極，則無死地之憂矣。孫子曰：戰貴地利。然則地利者，不可一概用也，但臨時觀其用何如爾。兵貴設變，不能以變用兵，雖得地利無益也。

High mountains and great marshes, dangerous obstacles and steep cliffs, muddy swamps and narrow paths, surrounded on all sides with no way to escape, this is precisely the opportunity for a cunning person to employ strategies. At this time, one should use surprise tactics to confuse the enemy and then attack. The surprise attack may involve using "fire horses" and "fire oxen" (binding torches to horses and oxen and sending them charging against the enemy), as used by Tian Dan and Yang Ban; or it may involve taking advantage of the darkness of night, pretending to use the enemy's signals, charging directly into the enemy's ranks, and mixing their uniforms and banners with those of the enemy so that they cannot distinguish them. If one relies solely on a desperate battle as the only hope, and if the enemy grows stronger while our reinforcements are ineffective, we will end up in the same dire situation as General Li Ling of the Han dynasty, whose bows broke and arrows were exhausted. Fighting until exhausted and falling dead is self-inflicted defeat. If one exhausts all wisdom and constantly changes tactics, there will be no fear of being trapped in a desperate situation. The "Art of War" says: warfare values gaining the advantage of terrain. However, so-called terrain advantage cannot be applied in a uniform way; it must be adapted to the situation as it arises. The use of troops is valuable in its ability to change and adapt. If one cannot use troops flexibly, even if one has the advantage of terrain, it is of no use.

舉兵用武，率以古法為用執之，與膠柱鼓瑟無異爾，未見決中者也。兵家之利，利在變通之機，觀其逆順。夫興師之際，當先探敵將才不才。設若敵將不能以兵法使眾，惟以勇敢為己任，我則順用古法待之也。或敵將善用古法，我則逆用古法待之也。夫用兵之奇，莫奇於設伏。設伏之奇，莫奇於新智。新智者，非不師古也，因古而反之爾。

When raising an army and engaging in warfare, if one rigidly follows ancient methods without adaptation, it is no different from the idiom "gluing the tuning pegs of a zither and playing it," which is a metaphor for being inflexible. Such an approach has never been seen to achieve a decisive victory in one strike. The advantage of military strategy lies in adaptability and the ability to assess whether the situation is favorable or unfavorable. Before launching an attack, one should first determine whether the enemy general is capable or not. If the enemy general does not understand how to apply military principles to command his troops, and instead relies solely on bravery as his duty, then we should follow the ancient methods to deal with him. However, if the enemy general is skilled in using ancient methods, we should instead use the opposite of those methods. The most extraordinary aspect of warfare is the use of ambushes; and the most extraordinary aspect of ambushes is the use of novel ideas.the so-called new ideas do not mean abandoning the teachings of ancient masters, but rather applying the ancient methods in reverse.

古人料敵，以其始來、戰陣未合，先以賤而勇者挑之，觀其號令、旗鼓之整與亂，士馬之強弱，營陣之偏正，行伍之齊肅散亂，言語之喧嘩緘黙，以定勝負焉。是以古法曰：若其眾喧旗亂，其卒自行自止，其兵或縱或橫，其追敗恐不及，見利恐不得，如此者將必無謀，雖眾可獲矣。許洞曰：如古人以此取功，茍敵人能料，我當順其所料，伏兵待之，以詐示之；俟彼出師，則發伏攻之。

Ancient generals assessed their enemies when the enemy had just arrived and the two armies had not yet engaged. They first sent low-ranking but brave soldiers to challenge the enemy, thereby observing whether the enemy's commands and banners were orderly or chaotic, whether their troops were strong or weak, whether their camp was crooked or properly arranged, whether their ranks were disciplined or disordered, and whether their voices were noisy or silent. Based on these observations, they could determine the outcome of the battle. Therefore, the ancient method states: if the enemy's voices are noisy, their banners are disordered, their soldiers move and stop independently, their formations fluctuate unpredictably, they pursue defeated troops desperately, and they seize opportunities greedily, then their general is certainly unskilled, and even though their forces are numerous, they can be captured. Xu Dong said: ancient generals achieved success by using this method, but now enemies also use this method to assess us. Therefore, we should follow what they expect, prearrange ambushes, and deliberately display these weaknesses to them. When they launch an attack, we then launch our ambush to attack them.

古法曰：杖而立者饑也，汲而先飲者渴也，見利不進者勞也，軍擾者將不重也，旗動者亂也，吏怨者倦也，懸瓶不反其舍者窮寇也，諄諄翕翕徐與人言者失其眾也，數顧者失其群也，來委謝者欲休息也。

Ancient methods state: soldiers standing with weapons in hand are hungry; those drawing water who drink first are thirsty; those who see an advantage but do not advance are exhausted; unrest in the camp indicates the general is not dignified; flags flapping wildly show the ranks are disordered; complaints from military officers indicate the entire army is weary; those who hang up water pots and cooking utensils and do not return to their barracks are desperate fugitives; a general who speaks in a low, murmuring tone to others has lost the soldiers' support; those who frequently look back are losing their subordinates' reliance; sending envoys to make indirect apologies indicates a desire for a truce.

許洞曰：觀古人以此料敵，今則不然，當令精銳吏士分而伏於要衝，使其勞倦殘傷者如饑渴失群之狀，或數搖動其旗，或數驚擾其眾，使吏士喧嘩，應敵人所料。茍出師襲我，則潛發所伏，出其不意擊之。

Xu Dong said: One can see that ancients used these signs to assess the enemy. Now we should do the opposite: disperse the elite soldiers and hide them in key positions, while leaving the tired and wounded troops exposed, appearing hungry and isolated. We should also constantly wave banners or deliberately disturb the troops, causing them to be noisy and disordered, exactly matching the enemy's expectations. If he attacks us, we should secretly launch the ambush troops to strike him unexpectedly.

古法曰：敵如來到，行陣未定，可擊也；跋涉長道，後行未息，可擊也；行阪涉險，半隱半出，可擊也；涉水半渡，可擊也；險道狹路，可擊也；旌旗亂動，可擊也；陣數動移，可擊也。

Ancient methods state: When the enemy has just arrived and their formation is not yet stable, attack; after a long march and the rear troops have not yet rested, attack; when crossing rugged terrain and half the troops are hidden behind the mountain while the other half are exposed, attack; when crossing water and only half have reached the other side, attack; when trapped in a narrow pass, attack; when banners are in disorder, attack; when the enemy's formation keeps changing and moving, attack.

許洞曰：在我則不然：如以行陣未定，四面可設伏也；長道移行未息，中可設伏也；山阪半隱半出，長林土穀可設伏也；涉水半渡，則崖岸坡阪可設伏也；狹路險道，則前後可設伏也；旗數亂動，陣數動移，前後可設伏也。如或敵人敗走，我師未敢逐之者，防有伏也。

Xu Dun said: When applying this strategy to our own side, we should reverse it: deliberately making the formation appear unstable, while setting ambushes on all four sides; deliberately showing the appearance of a long march with the rear not yet rested, while setting ambushes in the middle of the formation; partially hiding and revealing on a hillside, using the long woods and hills for ambushes; when crossing a river halfway, setting ambushes on the cliffs, slopes, and banks; when passing through narrow and dangerous paths, setting ambushes both in front and behind; and also setting ambushes in front and behind when the banners are chaotic and the formation keeps changing. Therefore, if the enemy retreats, our army dares not chase, precisely to guard against such ambushes.

古法曰：鳥起者伏也，眾樹動者來也。不如此，未必伏與來也，欲為疑兵也。我已奔遁，多令老弱者動其眾樹，及驚鳥起之類也。又曰：無約而請和者，謀也；半進半退者，誘也。此亦大兵已潛遁，恐後人逐者，設此為疑也。

Ancient methods say: if birds suddenly take flight, there may be hidden troops nearby; if a whole grove of trees shakes, the enemy is likely approaching. But when used in reverse, this may not be the case: there may not actually be hidden troops or an enemy coming, but rather a deliberate deception. For instance, if our side has already withdrawn, yet we send old and weak soldiers to shake the trees and startle the birds, this is exactly such a case. Ancient methods also say: if someone comes to seek peace without prior agreement, they have ulterior motives; if they advance half and retreat half, it is a lure. This may also indicate that our main force has already secretly withdrawn, fearing pursuit from behind, and deliberately displaying these appearances to confuse the enemy.

許洞曰：料敵以事者，多慮為反古之法也，多中為期，用之於人也。是以兵法如車之載其物，則車之轉者由輪也，及有車之用，則東西南北者由人也。故兵法不可執而用之也，明矣。

Xu Dong said: Those who predict the enemy based on specific signs should consider one more layer: the enemy might be using the ancient methods in reverse. The goal is to be able to predict accurately repeatedly, but ultimately it depends on who the method is applied to. Therefore, military strategy is like a cart carrying goods: the cart can move because of the wheels, but the direction to go east, west, south, or north is determined by the person driving. Therefore, military strategy should not be rigidly followed, and this principle is very clear.

凡水戰之具，船闊狹長短大小，載人多少，以米為則。一人重米一石，則人數積而可知也。棹、篙、櫓、帆、席、組、繩索、沉石、調度，與常船不殊。船上安樓三重，列女墻戰格，樹幡幟，開弩窗、矛穴、炮車，置壘木、鐵汁，狀如守城。

All equipment used in naval warfare, including the width, length, size, and capacity of the ship, is calculated by converting them into measures of rice: one person is equivalent to one shi of rice. By adding up the amount of rice, one can determine how many people the ship can carry. The oars, poles, paddles, sails, mats, ropes, anchor stones (stone anchors), and other equipment are the same as those on ordinary ships. Here we are talking about the 'lou ship' (a type of warship): it has three stories built on top of it, with 'nü qiang' (low protective walls) and 'zhan ge' (protective wooden fences) surrounding it, flags raised, openings for shooting arrows and thrusting spears, and mounted ballistae for throwing stones. It is also equipped with wooden stakes and molten iron, and its overall structure is similar to that of a fortified city.

王濬伐吳，作大船，長二百四十步，建飛簷閣道，可以奔馬馳車。忽遇大風，則人力不能制，甚不便戰鬥。然為水軍，不可不設，以張形勢。蒙衝，以犀蒙覆船，皆兩廂開制棹孔，前後左右有弩窗、矛穴，敵不得近，矢石不能敗。此不用大船，務於速進退，戰船也。

During the Western Jin dynasty, Wang Jun constructed large ships when he attacked Wu. These ships were 240 steps long, had flying eaves and corridors for running horses and carts. However, once encountering strong winds, human power could not control them, making them inconvenient for combat. Nevertheless, the naval forces had to keep a few of these ships to display strength. "Mengchong" ships were covered with tough rhinoceros hide, had oar holes on both sides of the hull, and openings for shooting bows and spears on all sides. Enemies could not approach them, and arrows and siege stones could not damage them. These ships did not seek large size, but rather quick movement, making them specialized warships.

鬥艦，艦船舷上設墻，可蔽半身，墻下開制孔。舷內五尺建柵為女墻，重列戰格，上無覆背。前後左右樹牙旗、金鼓，戰船也。走舸，舷上重列女墻、棹篙，多戰卒，選驍勇精銳者，奔走往反如飛鷗，乘人不及，旗幟金鼓列之於上，戰船也。

"Duojian" refers to warships with guard walls erected on the sides, high enough to cover half the body, with shooting holes below; another wooden fence is set up five feet inside the side walls, forming a second layer of guard rail, with closely arranged battle grids on top, without a roof; flags, drums, and banners are set up on all sides, making it a standard warship. "Zouge" refers to warships with multiple layers of guard rails on the sides, equipped with many oars and poles, carrying many soldiers, all selected as elite and brave warriors, moving swiftly like flying swans skimming the water, able to attack suddenly before the enemy can prepare, with flags and drums also set up on the ship, making it another type of warship.

遊艇，小艇船，無女墻，船上置木床，左右隨艇大小長短，四尺一床。計會進止，回軍轉陣，其疾如飛，虞候居止之，非戰船也。海鶻，頭低尾高，前小後大，如鶻之狀。左右置浮板，如鶻翅翼。雖風波漲大，無傾倒也。覆背上左右皆張生牛皮為之，建牙旗、金鼓如常法，江海之中戰船也。

A "youtou" is a small boat without a railing, with wooden beds placed on board. The number of beds is arranged according to the length of the boat, one bed for every four feet. It is used for transmitting orders, making arrangements, and signaling movements. When the army retreats or changes formation, it moves quickly like flying. It is the boat used by the "yuhou" (a military officer responsible for reconnaissance and patrols), not a warship. A "haigu" has a low bow and a high stern, with a small front and a large rear, resembling a hawk. It is equipped with floating boards on both sides, like the wings of a hawk, so that it does not capsize even in high waves. The top has protective cowhide covers on both sides, and it has vertical banners and gongs and drums, just like usual. It is a warship used in rivers and seas.

兵法曰：以水佐攻者強。善用水者，其道有四：一曰因，二曰逆，三曰賊，四曰絕。因水之用，其道有二：或敵絕中流而柵，我得上遊，因風之利，可以鼓棹縱火，順流沖之，柵絕而過，風轉則止；又若敵在下，士馬逆流，我得上遊，可以攻之。此二者，所謂因者也。

The *Art of War* by Sun Tzu says: Using water to assist in an attack increases its power. Those skilled in using water have four methods: one is called "following the trend," meaning using the natural flow; two is called "contrary," meaning blocking and diverting water; three is called "stealing," meaning secretly removing the water source; four is called "cutting off," meaning blocking the water flow. The methods of following the trend are two: first, if the enemy has blocked the river center with wooden barriers, and we occupy the upper stream, we can take advantage of the wind direction, row hard, and set fire to the barriers, breaking through them with the current, stopping when the wind changes; second, if the enemy is downstream and has to go against the current, we occupy the upper stream and attack them with the current. These two are called "following the trend."

逆水之用也，則為崇堤以障其下，註溢於內，然後引之以灌，所謂逆者也。賊水之用也，敵所以賴水也，當潛以水攻，審地理，陰為畎澮，導之他處，竭敵所賴，所謂賊也。

The method of "reverse" involves building a high embankment downstream to block the water, allowing it to accumulate and rise within the embankment. Then, breaking the embankment to divert the water and flood the enemy's forces. This is called "reverse." The method of "stealth" involves secretly attacking the water source that the enemy relies on. By investigating the terrain and secretly digging channels to redirect the water, the enemy's vital water supply is cut off. This is called "stealth."

絕水之用也，或以薪木土石，實舟沈之於上，別為長渠洩之；或為沙囊於上流以壅其水，欲水行則以決囊，所謂絕者也。用水之道，有其地非所用而必用，反為所害，順則善矣。

The method of "jué" involves either loading boats with firewood, earth, and stones, then sinking them upstream to block the river and diverting water through a long channel to release it; or using sandbags to block the flow upstream, and digging through the sandbags when water needs to be released. This is called "jué." The principle of using water is that some places are not suitable for water yet water is forced to be used, leading to harm; only by following the terrain and the nature of the water can one achieve true skill.

先量水之高下，水平水槽長二尺四寸，兩頭及中間鑿為三池，橫闊一寸二分。池間相去一尺五分。間有通水渠，闊二分，深一寸三分。三池各置浮木，闊狹微少於池。箱厚二分，上建立齒，高八分，闊一寸七分，厚一分。槽為轉開，腳高下與眼等。以水注之，三池浮木齊起，眇目視之，三齒齊平，則為天下準。

To use the water level method, one must first measure the height and level of the terrain. The instrument used is called "level" (水平). The water trough is two chi and four cun long. Three water basins are carved out at both ends and the middle of the trough. Each basin is one inch and two fen wide, and the distance between each basin is one chi and five fen. Between the basins, there are small channels for water flow, each two fen wide and one inch and three fen deep. In each basin, a floating piece of wood is placed, slightly narrower than the basin. The wood is two fen thick, and on top of it, a tooth-shaped marker is erected. The tooth is eight fen high, one inch and seven fen wide, and one fen thick. The water trough is mounted on a rotating and adjustable frame, with the height of the supports level with the viewer's eyes. Water is poured into the trough, and the floating wooden pieces in the three basins rise together. By squinting one eye, the three tooth markers are aligned in a straight line, forming the level reference for measuring elevation.

或十步，或一里，乃到數十里，因力所及，置照板、度竿，以白繩計其尺寸，則高下丈尺分寸可知。照板形如方扇，長四尺，下二尺，上二尺，面闊三尺，柄長一尺，大可握。

Then, every ten steps or every li, continuing until dozens of li away, they set up the "zhao pan" and "du gan" successively within sight, using white ropes to measure the dimensions. Thus, the height and measurements of the terrain at each location can be calculated. The zhao pan is shaped like a square fan, with a total length of four chi, divided into two sections of two chi each (colored differently for easy identification from a distance), a width of three chi, and a handle of one chi in length, with a thickness just right for one hand to hold.

度竿長二丈，克作二百寸，二千分。每寸內小克。隨所向遠近高下置竿，以照板映之，眇目視之，三浮木齒及照板以度竿上尺寸為高下，遞而往來，尺寸相乘，則山淵水源高下淺深，可以分寸度矣。

The measuring pole is two zhang long, marked with two hundred cun and two thousand parts. Within each cun, further subdivisions are made. Facing the direction to be measured, the pole is erected according to the distance and height. A mirror board is placed facing the pole, and one eye is closed to align the sight. When the teeth marks on the three floating woods align with the mirror board, the corresponding measurement on the pole is read. This process is repeated step by step, accumulating the measurements sequentially. Thus, the height and depth of mountains, valleys, and water sources can be accurately determined down to the finest fraction.

罌筏一，凡縛罌甕為筏，甕間闊五寸，深受三石米，力勝一。底以勾繩連之，編槍於上，形長而方，前置板頭，後置板梢，左右掉之。槍筏：槍十根為一束，力勝一人，四千一百六十根為一筏，去鉆刃束為魚鱗次，橫括而縛之。可渡四百一十六人。為三筏，計用一萬二千五十根，渡人一千二百五十人。十渡則一軍濟矣。

The first type is called "Ying Fa" (Drum Vessel Raft): clay jars and pots are tied together to form a raft. Each jar is spaced five inches apart, and each jar can hold three stones of rice, providing enough buoyancy to carry one person. The bottom of the raft is connected with ropes with hooks, and a long pole is placed across the top as the raft's surface. The raft is long and square in shape, with a bow board at the front and a stern board at the back. It is propelled by rowing on both sides. The second type is called "Qiang Fa" (Pole Raft): ten long poles are tied together to form a bundle, which can carry one person. Four thousand one hundred sixty poles are woven into one raft. First, the sharp points of the poles are removed, and the bundles are layered like fish scales, then tightly bound horizontally. One raft can carry four hundred sixteen people. If three rafts are made, using a total of twelve thousand and fifty poles, one thousand two hundred fifty people can be transported. With ten round trips, an entire army can cross the river.

挾ㄌ，以善水者繫小繩於要處，先浮大木，次引大ㄌ。於兩岸立大橛及繫於樹，急定ㄌ使人挾ㄌ浮渡。大軍可分為十道渡之。浮囊，以渾脫羊皮，吹氣令滿，繫其孔，束於腋下，兩浮而渡。

The third method is called 'xie lan' (the original character is a rare one, referring to a thick rope): having a skilled swimmer tie a thin rope around his waist, first pushing a large log across the river, then pulling the thick rope across. On both banks, large wooden stakes are driven into the ground, or the rope is tied to trees, and the rope is tightened and fixed. The people then hold onto the rope and float across the river. The army can be divided into ten groups to cross the river simultaneously. The fourth method is 'fu nang': taking a whole, unbroken sheepskin, blowing it up fully, sealing the air hole, and tying it under the armpits, with one on each side, floating across the water.

無水之地，擇地有黃羊糞者必有水。砂鹵甘潤者，下有水。細草蒙茸，與無水處不同者，亦如之。

Looking for water in an area where there is no water, one should choose places where there are yellow sheep droppings, as there is certainly water beneath them. In areas of sandy soil, stones, salt-alkali land, if the soil has a sweet and moist taste, there is water beneath. Also, where fine grass grows thick and lush, clearly different from the surrounding areas that have no water, this also indicates that there is water underground.

將有火之用，先知其日〈日者謂春丙丁、夏戊己、秋壬癸、冬甲乙，此日有大風雨故也〉，次順其風〈我得上風則放火燒，下風一作起馬〉。攻城寇寨，風助順，利為飛火〈飛火者，謂火炮火箭之類也〉。相守不動，利於奸火〈奸火者，因其人焚其積聚甲兵也〉。兩陣相合，禦風之便揚〈一作枵〉塵鼓煙，利為燧牛以俟之。若敵於上風放火，我亦縱火為解火法〈敵燒門恐火恐火威，我使積薪以伍外火亦此類也〉。

When using fire, first choose the right day (the term "day" refers to days in the spring with Bing and Ding stems, summer with Wu and Ji stems, autumn with Ren and Gui stems, and winter with Jia and Yi stems, because these days often have strong winds and rain). Second, follow the wind direction (if we are on the upwind side, we can set fire to the enemy; if we are on the downwind side, we need to plan otherwise, "downwind" is sometimes written as "qǐ mǎ"). When attacking a city or camp, if the wind is favorable, use "flying fire" (referring to fire weapons such as fire cannons and fire arrows that can be launched). When both armies are holding positions without moving, use "treacherous fire" (meaning bribing people within the enemy camp to burn their stored grain and military supplies). When two armies are engaged in battle, take advantage of the wind to raise dust and create smoke ("扬" is sometimes written as "xiāo"), and prepare "torch oxen" (oxen tied with torches) to be released at the right moment. If the enemy sets fire on the upwind side, we also set fire to create a firebreak, which is called the "fire relief" method (if the enemy burns our city gate, and we fear the fire will spread rapidly, we can pre-emptively pile firewood outside the gate and set it on fire to burn away all flammable materials, which also falls under this category).

凡入敵境，郡邑窮匱，城隍頹靡，山川非設險之地而非敵所恃者，則存之。茍拔敵所恃之邑，皆火之，以絕其望焉。敵境之林木筏草，皆火之。故火為兵之大利也。

Whenever entering an enemy's territory, those counties and towns that are poor and exhausted, with broken walls and ditches, and mountains and rivers that are not suitable for defense and fortification, should be left untouched and not burned. But once an enemy's stronghold is captured, it should be completely burned down to cut off their hope of regaining strength. The forests and timber suitable for making rafts within the enemy's territory should also be burned entirely. Therefore, fire is one of the great weapons in warfare.

月對〈一作在〉東壁、南箕、軫之夕，則設火候風以焚之〈四時亦其火利偏攻〉。以驍騎夜銜枚縛馬口，人負薪及束，カ火直抵敵營。一時舉火，營中驚亂，急而乘之；靜而不動，勿攻。

When the moon reaches the eastern Wall mansion, southern Winnowing Basket mansion and Chariot mansion, which are opposite to the Chariot mansion, it is the time when wind arises. Be prepared with firewood and wait for the wind to set fire to the enemy's camp. Each season has its own favorable time for fire attacks and ambushes. Send brave cavalry at night with bits in their mouths and their mouths tied, each carrying bundles of firewood and carrying fire starters to reach the enemy's camp. Agree on a signal to set fire at the same time. The enemy's camp will surely be in confusion, so attack quickly when they are disordered. If the enemy's camp remains quiet, do not attack.

火獸，以艾溫置瓢中，開四孔，繫野豬、獐、鹿項下，針其尾端，望敵營而縱之，奔走入草內，則火起。火禽，以胡桃空中實艾，開兩口，復合之，繫野雞項下，針其尾而縱之，飛宿於草上，則火發。

The method of "Fire Beast": place smoldering mugwort in a bowl, make four air holes on top of the bowl, tie it around the neck of a wild boar, mandarin duck, or deer, and prick its tail with a needle, then release it toward the enemy camp; as the beast runs into the grass, the fire will start. The method of "Fire Bird": hollow out a walnut, fill it with smoldering mugwort, make two holes on the shell, close it up, tie it around the neck of a pheasant, and prick its tail with a needle, then release it; when the pheasant flies down to rest on the grass, the fire will start.