Chapter 4
Sun Tzu said: In ancient times, those skilled in warfare first created conditions to render themselves invincible, and then waited for the opportunity when the enemy could be defeated. Achieving invincibility hinges on creating sufficient conditions oneself; defeating the enemy lies in the enemy presenting an exploitable vulnerability. Thus, those adept at war can ensure their own invincibility but cannot guarantee the enemy's defeat. Hence, victory can be predicted but not forced.
With invincible conditions in place, one can defend; when the enemy presents an opportunity for victory, one can attack. Defending should rely on one's own invincibility and abundant strength; attacking should target the enemy's weaknesses and deficiencies, ensuring victory with every strike. A skilled defender is like one buried deep underground, leaving no trace for the enemy to discern; a skilled attacker is like a divine army descending from the heavens, catching the enemy off guard. Thus, one can effectively preserve oneself while achieving comprehensive victory.
Foreseeing victory within the ordinary scope of insight is not the highest wisdom; winning a hard-fought battle and earning universal praise is not the ultimate excellence. Just as lifting a hair is not a sign of great strength, seeing the sun and moon is not a mark of sharp vision, and hearing thunder is not a sign of keen hearing, so too, ancient warriors who excelled in battle always sought victory against easily defeated enemies. Therefore, the victories of these adept warriors were neither adorned with the reputation of wisdom nor the glory of bravery. Their victories in war were flawless, and this flawlessness stemmed from their actions being predestined for victory, triumphing over enemies already poised for defeat. Those skilled in warfare always establish themselves in an unbeatable position without missing any opportunity to defeat the enemy. Consequently, victorious armies prepare the conditions for victory before engaging in battle, while defeated armies engage first and then hope for a fortunate victory amidst hardship. Those adept at employing troops always focus on refining politics and ensuring stringent military discipline, thereby becoming the masters of war's outcome.
In waging war, one must consider five factors: land area, military resources, troops' combat capability, the balance of power, and the potential for victory or defeat. The scale of land determines the availability of military resources, which in turn affects the quality of troops. The quality of troops determines combat effectiveness, and combat effectiveness ultimately decides victory or defeat. Therefore, victorious armies are like those with a pound (yì) against an ounce (zhū), leveraging their superior military strength to overcome weaker adversaries, while defeated armies are like those with an ounce against a pound, facing powerful enemies with inferior strength. Skilled commanders wage war like breaking open a dam of a thousand-foot-high mountain stream, unleashing a torrent—this is the power of superior military strength!
