8. The stronger men will be in front, the jaded ones will fall behind, and on this plan only one-tenth of your army will reach its destination. [The moral is, as Ts’ao Kung and others point out: Don’t march a hundred _li_ to gain a tactical advantage, either with or without impedimenta. Manœuvers of this description should be confined to short distances. Stonewall Jackson said: "The hardships of forced marches are often more painful than the dangers of battle." He did not often call upon his troops for extraordinary exertions. It was only when he intended a surprise, or when a rapid retreat was imperative, that he sacrificed everything for speed. [1] ] 9. If you march fifty _li_ in order to outmanœuver the enemy, you will lose the leader of your first division, and only half your force will reach the goal. [Literally, "the leader of the first division will be _torn away_."] 10. If you march thirty _li_ with the same object, two-thirds of your army will arrive. [In the _T’ung Tien_ is added: "From this we may know the difficulty of manœuvering."] 11. We may take it then that an army without its baggage-train is lost; without provisions it is lost; without bases of supply it is lost. [I think Sun Tzŭ meant "stores accumulated in dépôts." But Tu Yu says "fodder and the like," Chang Yu says "Goods in general," and Wang Hsi says "fuel, salt, foodstuffs, etc."] 12. We cannot enter into alliances until we are acquainted with the designs of our neighbours. 13. We are not fit to lead an army on the march unless we are familiar with the face of the country—its mountains and forests, its pitfalls and precipices, its marshes and swamps. 14. We shall be unable to turn natural advantages to account unless we make use of local guides. [§§. 12-14 are repeated in chap. XI. § 52.] 15. In war, practise dissimulation, and you will succeed. [In the tactics of Turenne, deception of the enemy, especially as to the numerical strength of his troops, took a very prominent position. [2] ] Move only if there is a real advantage to be gained. 16. Whether to concentrate or to divide your troops, must be decided by circumstances. 17. Let your rapidity be that of the wind, [The simile is doubly appropriate, because the wind is not only swift but, as Mei Yao-ch’en points out, "invisible and leaves no tracks."] your compactness that of the forest. [Meng Shih comes nearer to the mark in his note: "When slowly marching, order and ranks must be preserved"—so as to guard against surprise attacks. But natural forest do not grow in rows, whereas they do generally possess the quality of density or compactness.] 18. In raiding and plundering be like fire, [Cf. _Shih Ching_, IV. 3. iv. 6: "Fierce as a blazing fire which no man can check."] in immovability like a mountain. [That is, when holding a position from which the enemy is trying to dislodge you, or perhaps, as Tu Yu says, when he is trying to entice you into a trap.]