The Art of War by Sun Tzu

Master Sun

Therefore measure in terms of five things,
use these assessments to make comparisons,
and thus find out what the conditions are.
The five things are the way, the weather, the terrain, the leadership, and discipline.

Comments

Du Mu * Five things are to be assessed - the way, the weather, the lay of the land, the leadership, and discipline. These are to be assessed at headquarters - first assess yourself and your opponent in terms of these five things, deciding who is superior. Then you can determine who is likely to prevail. Having determined this, only then should you mobilize your forces.

Cao Cao * Assessments of the following items are to be made at headquarters: the leadership, the opponent, the terrain, troop strength, distance, and relative danger.

Wang Xi * Assess the leadership, the environmental conditions, discipline, troops, officers, and the system of rewards and punishments.

Zhang Yu * Master Guan said that assessments should be made at home before sending troops abroad. Assessments are the first order of business in military operations. Some say that military operations should be adjusted right on the spot, in confrontation with the opponent, but General Cao Cao says that assessments should be made at headquarters - this is because it is imperative first to assess the wisdom of the leaders, the strength of the opponent, the lay of the land, and the number of troops; then when the two armies confront one another, the adaptations to be made are determined by the leadership in a manner consistent with these calculations.
Discipline means that regulations are strict and clear. The reason that leadership and discipline come last in this list of five things is that whenever you mobilize to attack those who have done you wrong, it is necessary first to look into the matter of whether you are appreciated and trusted by your own people, then to assess the favorability or otherwise of weather conditions, and then examine the qualities of the terrain. Once these three things are fulfilled, then a leader is appointed to go forth on the expedition. Once the army has gone forth, all orders come from the general.

Wang Xi * Harmony among people is the basis of the Way of military operations; the right weather and an advantageous position help. When these three elements are present, then is the time to discuss mobilizing the army. Mobilizing the army requires ability on the part of the leadership. When the leadership is able, then there will be good discipline.