Chapter X

Sun Tzŭ enumerates six kinds of ground a general must learn to read: accessible, entangling, temporizing, narrow passes, precipitous heights, and positions at a great distance from the enemy.

On ground freely traversable by both sides, victory comes to whoever first occupies the raised, sunny spots and guards their supply lines.

Ground that's easy to leave but hard to retake punishes a failed attack; if the enemy is unprepared sally forth, but never strike unless retreat is unnecessary.

When neither side gains by moving first, refuse the bait, retreat to draw the enemy out, then attack only when part of his force has committed.

Garrison narrow passes first if you can. If the enemy has them, attack only when the garrison is weak.

Take the high, sunny ground first if you can. If the enemy holds it, retreat and lure him down rather than charge up.

If both armies are equal and far apart, fighting is to your disadvantage. These six terrain principles are the natural laws of Earth — the responsible general must master them.

Sun Tzŭ catalogs six failure modes — flight, insubordination, collapse, ruin, disorganization, rout — none caused by terrain or fate, all caused by the general's own faults. These are six ways of courting defeat.

Beyond knowing terrain, the great general estimates the adversary, judges his own forces, and shrewdly weighs distances. He fights only when victory is sure, retreats without fear of disgrace, and treats his soldiers as his own children — but with discipline, lest they become spoiled.

Sun Tzŭ adds a third dimension to self-knowledge: knowing your own readiness is half the battle, knowing the enemy's vulnerability is the other half, but knowing the ground completes victory. Know enemy and self and victory is not in doubt; know Heaven and Earth too and victory is complete.