10. Terrain
3
With regard to ground of this nature, be before the enemy in occupying the raised and sunny spots, and carefully guard your line of supplies.
The general meaning of the last phrase is doubtlessly, as Tu Yu says, "not to allow the enemy to cut your communications." In view of Napoleon's dictum, "the secret of war lies in the communications,"[1=See "Pensees de Napoleon 1er," no. 47.] we could wish that Sun Tzu had done more than skirt the edge of this important subject here and in I. ss. 10, VII. ss. 11. Col. Henderson says: "The line of supply may be said to be as vital to the existence of an army as the heart to the life of a human being. Just as the duelist who finds his adversary's point menacing him with certain death, and his own guard astray, is compelled to conform to his adversary's movements, and to content himself with warding off his thrusts, so the commander whose communications are suddenly threatened finds himself in a false position, and he will be fortunate if he has not to change all his plans, to split up his force into more or less isolated detachments, and to fight with inferior numbers on ground which he has not had time to prepare, and where defeat will not be an ordinary failure, but will entail the ruin or surrender of his whole army."[2="The Science of War," chap. 2.]