Terrain

Chapter 10 opens with a classification of six terrain types, each with its rule. Accessible ground can be freely crossed by both sides; occupy the high, sunny positions first and secure supply lines. Entangling ground can be left but not easily returned to; strike the enemy before they prepare, but if they are ready and you fail, the retreat becomes your problem. Stalemate ground benefits neither side from moving first; even if the enemy offers tempting bait, do not advance — retreat and lure them forward. With narrow passes, garrison them heavily if you arrive first; attack a weak garrison if the enemy holds them. With steep heights, take the sunny ground first; if the enemy holds the heights, retreat and try to draw them down. If you are far from the enemy and forces are equal, it is difficult to provoke battle — and fighting will be disadvantageous.

The chapter turns from terrain to command failure, classifying six types. Flight: a force thrown against one ten times its size. Insubordination: soldiers too aggressive, officers too weak. Collapse: officers overbearing, soldiers passive. Ruin: senior officers resentful and insubordinate, engaging the enemy on their own initiative without authorization. Disorganization: the commander is weak and unclear, roles undefined, formations chaotic. Rout: sending a small or weak force against a large or strong one without adequate assessment. These six failures are not failures of terrain — they are failures of command. Any commander in a position of responsibility must study them carefully.

The chapter closes with the principle that unifies both classifications. Terrain is the soldier's greatest ally — but the ability to assess the enemy, control the conditions for victory, and accurately judge the difficulty of the terrain is the difference between the general who wins and the one who loses. If analysis says you will win, fight — even if the ruler says not to. If analysis says you will lose, do not fight — even if the ruler orders it. Treat soldiers as your own children, and they will follow you into the deepest danger. But if you are generous without enforcing authority, kind without demanding obedience, you will produce a spoiled army that cannot be used.