the expediency of aggressive or defensive tactics; and the fundamental laws of human nature: these are things that must most certainly be studied.
42. When invading hostile territory, the general principle is, that penetrating deeply brings cohesion; penetrating but a short way means dispersion.
43. When you leave your own country behind, and take your army across neighbouring territory, you find yourself on critical ground.
This “ground” is cursorily mentioned in chapter VIII, paragraph 2, but it does not figure among the nine situations of this chapter or the six kinds of terrain in chapter X. One’s first impulse would be to translate it [as] “distant ground” (. . . in the sense of “distant lands”), but this . . . is precisely what is not meant here. Mei Yao-ch’ên says it is “a position not far enough advanced to be called ‘facile,’ and not near enough to home to be called ‘dispersive,’ but something between the two.”
That, of course, does not explain the name, which seems to imply that the general has severed his communications and temporarily cut himself off from his base. Thus, Wang Hsi says: “It is ground separated from home by an interjacent state, whose territory we have had to cross in order to reach it. Hence it is incumbent on us to settle our business there quickly.” He adds that this position is of rare occurrence, which is the reason why it is not included among the six kinds of terrain.
When there are means of communication on all four sides, the ground is one of intersecting highways.
44. When you penetrate deeply into a country, it is serious ground. When you penetrate but a little way, it is facile ground.
45. When you have the enemy’s strongholds on your rear, and narrow passes in front, it is hemmed-in ground. When there is no place of refuge at all, it is desperate ground.
46. Therefore, on dispersive ground, I would inspire my men with unity of purpose.
This end, according to Tu Mu, is best attained by remaining on the defensive, and avoiding battle.
On facile ground, I would see that there is close connection between all parts of my army.
As Tu Mu says, the object is to guard against two possible contingencies: “(1) the desertion of our own troops; (2) a sudden attack on the part of the enemy.” Mei Yao-ch’ên says: “On the march, the regiments should be in close touch; in an encampment, there should be continuity between the fortifications.”
47. On contentious ground, I would hurry up my rear.
This is Ts’ao Kung’s interpretation. Chang Yü adopts it, saying: “We must quickly bring up our rear, so that head and tail may both reach the goal.” That is, they must not be allowed to straggle up a long way apart. Mei Yao-ch’ên offers another equally plausible explanation: “Supposing the enemy has not yet reached the coveted position, and we are behind him, we should advance with all speed in order to dispute its possession.” . . .
Ch’ên Hao, on the other hand, assuming that the enemy has had time [to] select his own ground, quotes [Sun Tzu’s admonition] against coming exhausted to the attack. His own idea of the situation is rather vaguely expressed: “If there is a favourable position lying in front of you, detach a picked body of troops to occupy it; then if the enemy, relying on their numbers, come up to make a fight for it,
you may fall quickly on their rear
with your main body, and victory will be assured.” It was thus, he adds, that Chao Shê beat the army of Ch’in.
48. On open ground, I would keep a vigilant eye on my defences.
As Wang Hsi says, “fearing a surprise attack.”
On ground of intersecting highways, I would consolidate my alliances.
49. On serious ground, I would try to ensure a continuous stream of supplies.
The commentators take this as referring to forage and plunder, not, as one might expect, to an unbroken communication with a home base.
On difficult ground, I would keep pushing on along the road.
[Ts’ao Kung puts it thus:] “Pass away from it in all haste.”
50. On hemmed-in ground, I would block any way of retreat.
[Mêng Shih says:] “To make it seem that I mean to defend the position, whereas my real intention is to burst suddenly through the enemy’s lines.” [Mei Yao-ch’ên says:] “In order to make my soldiers fight with desperation.” [Wang Hsi says:] “Fearing lest my men be tempted to run away.” Tu Mu points out that this [injunction] is the converse of chapter VII, paragraph 36, where it is the enemy who is surrounded.
In 532 A.D., Kao Huan, afterwards Emperor and canonised as Shên-wu, was surrounded by a great army under Êrh-chu Chao and others. His own force was comparatively small, consisting only of 2000 horse and something under 30,000 foot. The lines of investment had not been drawn very closely together, gaps being left at certain points. But Kao Huan, instead of trying to escape, actually made a shift to block all the remaining outlets himself by driving into them a number of oxen and donkeys roped together. As soon as his officers and men saw that there was nothing for it but to conquer or die, their spirits rose to an extraordinary pitch of exaltation, and they charged with such desperate ferocity that the opposing ranks broke and crumbled under their onslaught.
On desperate ground, I would proclaim to my soldiers the hopelessness of saving their lives.
Tu Yu says: “Burn your baggage and impedimenta, throw away your stores and provisions, choke up the wells, destroy your cooking-stoves, and make it plain to your men that they cannot survive, but must fight to the death.” Mei Yao-ch’ên says epigrammatically: “The only chance of life lies in giving up all hope of it.” This concludes what Sun Tzu has to say about “grounds” and the “variations” responding to them.
Reviewing the passages which bear on this important subject, we cannot fail to be struck by the desultory and unmethodical fashion in which it is treated. Sun Tzu begins abruptly in chapter VIII, paragraph 2, to enumerate “variations” before touching on “grounds” at all, but only mentions five, namely nos. 5, 7, 8 and 9 of the subsequent list, and one that is not included in it. A few varieties of ground are dealt with in the earlier portion of chapter IX, and then chapter X sets forth six new grounds, with six variations of plan to match. None of these is mentioned again [until] at last, in chapter XI, we come to the Nine Grounds
par excellence
, immediately followed by the variations. . . .