摘要：孙子曰：凡用兵之法，将受命于君，合军聚众，圮地无舍，衢地交合，绝地无留，围地则谋，死地则战，涂有所不由，军有所不击，城有所不攻，地有所不争，君命有所不受。故将通于九变之地利者，知用兵矣；将不通九变之利者，虽知地形，不能得地之利矣，治兵不知九变之术，虽知五利，不
九变篇 Variation in Tactics
【原文】
孙子曰：凡用兵之法，将受命于君，合军聚众，圮地无舍，衢地交合，绝地无留，围地则谋，死地则战，涂有所不由，军有所不击，城有所不攻，地有所不争，君命有所不受。故将通于九变之地利者，知用兵矣；将不通九变之利者，虽知地形，不能得地之利矣，治兵不知九变之术，虽知五利，不能得人之用矣。
是故智者之虑，必杂于利害。杂于利而务可信也，杂于害而患可解也。
是故屈诸侯者以害，役诸侯者以业，趋诸侯者以利。
故用兵之法，无恃其不来，恃吾有以待也；无恃其不攻，恃吾有所不可攻也。
故将有五危：必死，可杀也；必生，可虏也；忿速，可侮也；廉洁，可辱也；爱民，可烦也。凡此五者，将之过也，用兵之灾也。覆军杀将，必以五危，不可不察也。
【译文】
孙子说：大凡用兵的原则是，将帅接受国君的命令，聚集民众组成军队，在山林、险阻、沼泽等难以通行的地方不要驻扎宿营；在四通八达、与邻国相交的地方要与邻国结交；在没有井、泉，无从畜牧和樵采，难以生存的地方不要久留；在四面险阻、通道狭窄、容易被敌人包围的地方，要提高警惕，巧设奇谋；在没有出路、非死战不得生存的地方要殊死奋战。有的道路不要去走；有的敌军不要去攻击，有的城池不要去攻占，有的地方不要争夺；将已受命之后，国君的命令有时可以不接受。所以，将若精通于九变之利害，就算懂得用兵了。将若不精通于九变之利害，虽然熟悉地形，也不能利用好地形；将若不精通九变全面之术，虽然知道前五种利害关系，也不能很好地发挥军队的战斗力啊！
所以高明的将帅考虑问题，一定要兼顾利和不利两个方面。在有利的情况下想到不利的一面，事情就可以顺利进行；在不利的情况下想到有利的一面，祸患就可以解除。
所以要使列国诸侯的行军计划遭到挫折，就要用他们最厌恶的事情去扰乱他们；要使列国诸侯烦劳困顿，就要用琐碎的事情去干扰他们；要使列国诸侯被动奔走，就要用小利去引诱他们。
所以用兵的原则，不要指望敌人不来，而要依靠自己做好充分准备等待敌人来；不要指望敌人不进攻，而要依靠自己具有不可攻破的力量使之不敢进攻。
所以将帅有五种危险：一味死拼，就可能中计被杀；怯弱贪生，就可能被敌人俘虏；急躁易怒，就可能被敌人凌侮而轻举妄动；廉洁好名，过于自尊，就可能被敌人羞辱而失去理智；溺爱民众，就可能因救护民众而陷于被动。以上五种偏激的性情，是将帅易犯的过失，是用兵的祸害。全军覆没，将帅被杀，必然由这五种危险引起，这是不能不深思熟虑的。
【英文】
Sun Tzu said: In war, the general receives his commands from the sovereign, collects his army and concentrates his forces. When in difficult country, do not encamp. In country where high roads intersect, join hands with your allies. Do not linger in dangerously isolated positions. In hemmed-in situations, you must resort to stratagem. In desperate position, you must fight. There are roads which must not be followed, armies which must be not attacked, towns which must be besieged, positions which must not be contested, commands of the sovereign which must not be obeyed. The general who thoroughly understands the advantages that accompany variation of tactics knows how to handle his troops. The general who does not understand these, may be well acquainted with the configuration of the country, yet he will not be able to turn his knowledge to practical account. So, the student of war who is unversed in the art of war of varying his plans, even though he be acquainted with the Five Advantages, will fail to make the best use of his men.
Hence in the wise leader's plans, considerations of advantage and of disadvantage will be blended together. If our expectation of advantage be tempered in this way, we may succeed in accomplishing the essential part of our schemes. If, on the other hand, in the midst of difficulties we are always ready to seize an advantage, we may extricate ourselves from misfortune.
Reduce the hostile chiefs by inflicting damage on them; and make trouble for them, and keep them constantly engaged; hold out specious allurements, and make them rush to any given point.
The art of war teaches us to rely not on the likelihood of the enemy's not coming, but on our own readiness to receive him; not on the chance of his not attacking, but rather on the fact that we have made our position unassailable.
There are five dangerous faults which may affect a general: ①Recklessness, which leads to destruction; ② cowardice, which leads to capture; ③ a hasty temper, which can be provoked by insults; ④ a delicacy of honor which is sensitive to shame; ⑤ over-solicitude for his men, which exposes him to worry and trouble. These are the five besetting sins of a general, ruinous to the conduct of war. When an army is overthrown and its leader slain, the cause will surely be found among these five dangerous faults. Let them be a subject of meditation.
来源：齐鲁晚报网