Terrain

Sun Tzu said: There are six types of terrain—open, confined, advantageous, pass, perilous, and distant. Terrain where our army can go and the enemy can come is called open. On open terrain, occupy the high ground and secure the lines of supply. This is advantageous. Terrain where it is easy to advance but difficult to retreat is called confined. In confined terrain, if the enemy is unprepared, launch a sudden attack to win victory. If the enemy is prepared, however, and we cannot win by attacking, and it is difficult to retreat, this is disadvantageous. Terrain where neither side has the advantage for attack is called advantageous. On advantageous terrain, if the enemy tempts us with small advantages, do not engage. Instead, withdraw first and counterattack when the enemy is halfway through their advance to win victory. In mountainous terrain with narrow passes, if we occupy it first, station troops at the passes to await the enemy. If the enemy occupies the passes first and stations troops to defend, do not attack. If the enemy occupies only part of the passes and has not fully blocked them, then attack. In perilous terrain, if we occupy it first, select a high and sunny position to await the enemy. If the enemy occupies the perilous terrain first, withdraw and do not attack uphill. In distant terrain, where both sides have equal ground, do not challenge the enemy; forcing a battle is disadvantageous. These six principles are the guidelines for using terrain. Mastering these principles is essential for a commander and must be carefully studied.

In military affairs, there are six conditions that lead to defeat: flight, relaxation, entrapment, disintegration, confusion, and rout. These six conditions are not caused by natural disasters or terrain but are the faults of the commander. When facing equal terrain but outnumbered ten to one, the army will inevitably flee; this is called flight. When soldiers are fierce but officers are weak and command is lax, this is called relaxation. When officers are fierce but soldiers are weak, combat effectiveness will be poor; this is called entrapment. When subordinate commanders are resentful and disobedient, encountering the enemy in anger and fighting without authorization, while the commander does not understand their abilities and tries to control them, the army will inevitably disintegrate; this is called disintegration. When the commander is incompetent and cannot strictly discipline the troops, with unclear theories and methods for training and education, leading to tense and chaotic relations between officers and soldiers, and a disorganized battle formation, this is called confusion. When the commander cannot assess the enemy situation, using a small force to resist the enemy's main force, fighting weak against strong without a elite vanguard, this is called rout. These six conditions are all paths to defeat and are crucial responsibilities for commanders, which must be carefully studied.

Terrain is an auxiliary condition in warfare. Assessing the enemy situation, formulating strategies for victory, and examining the distance and difficulty of terrain are responsibilities that a commander must fulfill. Those who understand these factors and command the battle will win; those who do not understand them and command the battle will lose. Therefore, from the perspective of the principles of warfare, if victory is assured, even if the ruler orders not to fight, the commander should still fight. Conversely, if there are no conditions for victory based on the actual situation of the war, even if the ruler insists on fighting, the commander should not engage. In summary, attacking the enemy should not seek false glory, and retreating and defending should not avoid blame. Only knowing how to protect the people and benefit the ruler can one be considered a pillar of the state.

Treating soldiers as if they were one's own infants will enable them to follow one into the abyss. Treating soldiers as if they were one's own sons will enable them to share life and death with one. However, if soldiers are pampered but not utilized properly, and if they break the law and discipline without punishment, they will be like spoiled children and cannot be used in battle.

Knowing when our soldiers can attack but not knowing when the enemy cannot be attacked gives us only half a chance of victory. Knowing when the enemy can be attacked but not knowing when our soldiers cannot attack also gives us only half a chance of victory. Knowing when the enemy can be attacked, knowing when our soldiers can attack, but not knowing when the terrain is unfavorable for battle gives us only half a chance of victory. Therefore, those who know how to use troops act with precision and decisiveness, adapting their actions to changing circumstances with infinite variety. Hence, understanding the enemy and oneself ensures continuous victory; mastering the heavens, earth, and terrain ensures endless victory.