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." Cf. VII. § 17. Mei Yao-ch’en 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 Yu 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’en 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’en Hao, on the other hand, assuming that the enemy has had time to select his own ground, quotes VI. § 1, where Sun Tzŭ warns us 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 She beat the army of Ch’in. (See p. 57.)]
48. On open ground, I would keep a vigilant eye on my defences. 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.
50. On hemmed-in ground, I would block any way of retreat.
[Meng Shih says: "To make it seem that I meant to defend the position, whereas my real intention is to burst suddenly through the enemy’s lines." Mei Yao-ch’en 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 is the converse of VII. § 36, where it is the enemy who is surrounded. In 532 A.D., Kao Huan, afterwards Emperor and canonized as Shen-wu, was surrounded by a great army under Erh-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.]