Commanding troops should be like the flow of water. Water runs from a high point to a low one. Troops should avoid attacking where the enemy defense is strong but instead attack where its defense is weak. Just as the flow of water is determined by terrain, war fighting should be based on the assessment of the enemy’s situation to secure victory. Hence there is no set formation for troops and no set shape for water. The one who can win by understanding the enemy’s situation can be called a godlike commander. (The Art of War)