Original Text
Sun Tzu said: Those skilled in ancient warfare first made themselves invincible, then waited for the enemy to become vulnerable. Invincibility depends on oneself; vulnerability depends on the enemy. Therefore, the skilled warrior can make himself invincible but cannot force the enemy to be vulnerable. Thus it is said: victory can be foreseen, but not forced.
When invincible conditions are present, one can defend; when the enemy shows a vulnerability, one can attack. Defense is employed when strength is insufficient and conditions for victory are not fully met; offense is taken when strength is superior and the enemy is relatively weak. Those skilled in defense hide as deep as the earth, leaving no trace for the enemy to find; those skilled in attack strike with supreme mobility and flexibility, like a divine force descending from the sky, catching the enemy off guard. Thus, an army adept at both defense and offense can preserve itself and conquer the enemy.
Foreseeing victory without surpassing ordinary insight is not the highest form of wisdom; winning after battle, even if praised by all under heaven, is still not the highest form of wisdom. This is like being able to lift an autumn hair but not being considered strong, being able to see the sun and moon but not being considered sharp-eyed, or being able to hear thunder but not being considered keen-eared. The ancient masters of warfare simply overcame enemies who were already easy to defeat. Therefore, these masters of warfare achieved victories without remarkable feats, without a reputation for strategic brilliance, or credit for courageous might. This is because their victories were inevitable and absolutely free from error. The reason for no error is that their measures for victory were built on an unshakable foundation, overcoming enemies who were already in a position of defeat. Thus, the skilled warrior first establishes an invincible position and never misses any opportunity to defeat the enemy. Therefore, a victorious army first creates conditions for certain victory, then seeks battle; a defeated army often rushes into battle first, then hopes for a lucky outcome through hard fighting. The skilled warrior is always able to cultivate governance and follow the law, thereby becoming the master of victory and defeat.
In military strategy, the factors used to measure victory or defeat are: first, "measurement" — the extent of territory; second, "estimation" — the resources and supplies; third, "count" — the combat strength of troops; fourth, "comparison" — the relative comprehensive military power; fifth, "outcome" — the judgment of victory or defeat. The breadth of the opposing sides' territories determines the extent of their land. The extent of land determines the abundance or scarcity of military resources. The difference in resources determines the number of troops. The difference in troop numbers determines the relative military strength. The difference in military strength ultimately determines the outcome of war. Thus, a victorious army is to a defeated one as a yi is to a zhu — overwhelmingly superior. A defeated army is to a victorious one as a zhu is to a yi — utterly inferior. When one side holds the advantage in power, commanding soldiers in battle is like releasing pent-up water from a thousand-ren-high ravine — an unstoppable force. This is what is meant by "strategic positioning."
Commentary
This chapter's military posture is closely related to the next chapter's strategic advantage, yet they are distinctly different.
This chapter primarily discusses adopting offensive or defensive forms based on the relative military strength of both sides, proposing the guiding principle of first securing an invulnerable position, then seeking victory. The term "form" in this chapter has two meanings: first, it refers to objective combat conditions such as the quantity of supplies, troop numbers, and combat effectiveness—quantifiable elements; second, it denotes a strategic posture generated from the comparison between the two sides, resulting from the combined effect of various objective factors.
Example Interpretation】
The Battle of Handan
In 262 BC, the state of Han was attacked by Qin, which captured the territories of Xing, Gaoping, Shaoqu, and Yewang. The King of Han, terrified, offered to cede the Shangdang Commandery to sue for peace. However, Feng Ting, the governor of Shangdang, refused to surrender the land to Qin. To shift the conflict, he instead offered the commandery to the state of Zhao. The King of Zhao, driven by greed, accepted the territory, provoking Qin's displeasure. As a result, Qin launched a military campaign against Zhao.
In 260 BC, the Qin and Zhao armies clashed decisively at Changping. Qin general Bai Qi, recognizing Zhao Kuo's tendency to engage in empty theorizing and reckless overconfidence, devised a strategy of feigned retreat to lure the enemy, followed by encirclement and annihilation, wiping out over 400,000 Zhao troops. After his victory, Bai Qi sought to press the advantage and destroy Zhao entirely. He divided his Qin forces into three groups: one to capture key points west of Handan like Wu'an, another to march north and seize Taiyuan Commandery, while he personally led a contingent to remain in Shangdang Commandery, preparing to attack Handan.
The offensive momentum of the Qin army instilled fear in the state of Zhao and its neighboring states. To avoid destruction, Zhao conspired with Han and sent Su Dai with heavy treasures to lobby Qin's prime minister, Fan Ju. Su Dai swayed Fan Ju's resolve to destroy Zhao by addressing both his personal interests and Qin's gains and losses, while also proposing territorial concessions in exchange for peace. Persuaded by Su Dai's analysis, Fan Ju advised the King of Qin to accept Zhao's offer of land for peace. Considering that the Battle of Changping had lasted three years, and although Qin had emerged victorious, over half of its soldiers had died, leaving the state impoverished and its people starving, the King of Qin agreed. He accepted Han's cession of Tanyong and Zhao's cession of six cities to Qin, thus reaching a peace agreement. In the first month of 259 BCE, the King of Qin withdrew his troops.
After Qin withdrew its troops, the King of Zhao prepared to cede six cities to Qin according to the peace treaty. However, Zhao's prime minister, Yu Qing, disagreed with the cession. He analyzed that Qin's withdrawal was due to its troops being exhausted and lacking strength. If Zhao now gave land to Qin, it would be no different from encouraging Qin to attack Zhao. Given Qin's ambition, if Zhao ceded six cities every year, it would soon be destroyed. He suggested to the King of Zhao that the six cities be used as a bribe to Qi, as Qi harbored deep resentment toward Qin. If Qi received the six cities from Zhao, it would surely be willing to join forces with Zhao to attack Qin. In this way, although Zhao gave cities to Qi, it could compensate by seizing Qin's territory. By then, Qin would instead seek peace with Zhao, and Han and Wei would also respect Zhao, thus forming an alliance with Qi, Han, and Wei. The King of Zhao adopted Yu Qing's advice but, anticipating that Qin would not let the matter rest, actively prepared to resist Qin.
The State of Zhao learned from the lessons of the Battle of Changping and devised a series of domestic and diplomatic strategies. Internally, the Zhao ruler and his ministers worked to ease internal conflicts, uniting their efforts to govern the state. They focused on developing agriculture to strengthen national power, raising orphans to increase the population, and reorganizing military equipment to enhance combat effectiveness. At the same time, they harnessed the people's outrage over the Qin army's massacre of surrendered Zhao troops at Changping to inspire the entire nation to share a common hatred against the enemy, thereby creating a favorable situation where the whole country rose up to resist Qin. Externally, Zhao actively pursued alliance-building activities. The Zhao king sent Yu Qing east to meet with the Qi king to discuss plans for a united front against Qin; took advantage of a Wei envoy's visit to Zhao to negotiate an alliance, signing a treaty with Wei; granted Lingqiu as a fief to Lord Chunshen, the prime minister of Chu, to secure good relations with Chu; and also made great efforts to win over Han and Yan. All these efforts led to the formation of a united anti-Qin force, establishing a unified front against Qin.
King Zhao of Qin was indeed enraged that Zhao had not ceded the promised territories as agreed, but instead allied with other states to oppose him. In September 259 BC, he sent Wang Ling to lead an army to attack Zhao, and the troops quickly reached Handan, the capital of Zhao. Facing the reality of a stronger enemy and a weaker self, Zhao adopted a strategy of holding firm to exhaust the enemy, sustaining a prolonged defense, avoiding decisive battles, and awaiting foreign reinforcements. The people of Zhao still vividly remembered the brutality of the Qin army. The invasion ignited the resolve of Zhao's soldiers and civilians to resist steadfastly and fight to the death to defend their country. They held Handan and fought valiantly. During the defensive stand, they often dispatched elite troops to seize opportunities to strike the Qin army, inflicting heavy losses. Qin's assault on Handan was thwarted. The King of Qin then reinforced and replaced his generals, continuing the offensive. After eight or nine months of combat, the Qin army suffered severe casualties but still failed to capture Handan. Furious, the King of Qin personally summoned General Bai Qi to lead the attack on Zhao. Earlier, when the king and his advisors discussed launching the campaign, Bai Qi had opposed it. He told the king: "Since Zhao's defeat at Changping, Qin missed the chance to destroy them, giving Zhao time to recover. They have worked hard on farming to build reserves, reorganized their armor to strengthen combat power, and repaired city walls to fortify defenses. Now, domestically, Zhao is united in shared hatred, striving to enhance national strength and military readiness. Externally, Zhao is actively forging alliances with other states against Qin. Under these circumstances, it is difficult to defeat Zhao." Now that Bai Qi's prophecy had come true, the king again asked him to command the campaign at Handan. Bai Qi refused, saying, "I would rather suffer death by severe punishment than be a general who disgraces the army." The king flew into a rage and ultimately forced him to commit suicide by presenting him with a sword.
The Qin army besieged Handan for a long time without success, finding itself in an awkward position of exhaustion and indecision. At this time, while holding firm in Handan, Zhao actively pursued alliances. Lord Pingyuan, Zhao Sheng, led Mao Sui and others to seek aid from Chu. Mao Sui provoked the King of Chu by recalling past grievances—how the Qin army had once breached Yingdu, burned Yiling, and forced Chu to relocate its capital—prompting the king to agree to send troops north to rescue Zhao. The King of Wei also promised aid, dispatching 100,000 troops toward Handan. Upon hearing this, the King of Qin sent an envoy to threaten the King of Wei, saying: "Whoever sends troops to rescue Zhao, once I capture Handan, I will turn my forces against them." Fearing future retaliation from Qin, the King of Wei ordered General Jin Bi to station the 100,000 troops at Ye, where they remained idle and hesitant.
Lord Pingyuan, Zhao Sheng, seeing that the Wei army had halted its advance, sent a messenger to Wei, asking his brother-in-law, Lord Xinling of Wei, to find a way to persuade the King of Wei to order the troops to march to Handan. Lord Xinling repeatedly urged the King of Wei, but the king still refused to issue the order to advance. Finally, following the advice of his retainers, Lord Xinling had Ru Ji steal the tiger tally, pretended to act on the king's command to replace Jin Bi. Jin Bi grew suspicious and refused to hand over military authority. Forced into action, Lord Xinling killed Jin Bi, seized command of the army, and led the troops directly to Handan.
At that time, Handan's situation was extremely precarious. The Lord of Pingyuan conscripted his wives, concubines, and servants into the city's defense labor, donated all his family wealth to the soldiers, and encouraged them to fight to the death. He also recruited 3,000 fearless warriors to launch a counterattack against the Qin army. Caught off guard, the Qin forces faltered and retreated 30 li. Just then, the Wei relief army led by Lord Xinling and the Chu army led by Lord Chunshen arrived one after another. Under attack from both sides, the Qin army was defeated at Handan. Some of the remaining Qin troops fled to Fencheng, while others were surrounded by the allied forces and eventually surrendered to Zhao.
The allied forces of Wei, Chu, and Zhao, emboldened by their victory, advanced to Hedong. The Qin army retreated to Hexi, relinquishing the previously occupied Wei territory of Hedong, Zhao territory of Taiyuan, and Han territory of Shangdang. Thus, the Battle of Handan came to a close.
In the Battle of Handan, the key to Zhao's victory over a stronger enemy lay in its strategy to remain invincible. This included easing internal conflicts to win popular support, which Sun Tzu described as "cultivating the Way and upholding the law." At the same time, Zhao adopted a strategy of primarily defense combined with offense. When the enemy's troops became exhausted and their edge dulled, Zhao seized the opportune moment, coordinated with allied reinforcements, and launched a decisive attack, defeating the Qin army. The Qin's failure resulted from King Zhao of Qin disregarding military principles and rashly starting a war under unfavorable conditions. Sun Tzu said, "Victory can be known but not forced." The outcomes of the Battle of Handan offer valuable lessons for future generations.