Zhao Kuo was the son of Zhao She, a general of the Zhao State. In 280 BC, the King of Zhao ordered Zhao She to attack Maiqu in the State of Qi, so Zhao She brought his son Zhao Kuo along to Maiqu. Before their arrival, the Zhao army had already attacked Maiqu many times, all ending in failure. The King of Zhao then appointed Zhao She as the general, demanding that he capture Maiqu within a month.
With the King of Zhao's orders, Zhao She immediately launched an attack upon arriving at Maiqiu. However, Zhao Kuo believed that since the Qi army's defenses at Maiqiu were solid and Zhao forces had already failed to capture it after many assaults, a direct attack would only deplete their own strength. To take Maiqiu within a month, he thought they should find another approach. He reasoned that since the Zhao army had besieged Maiqiu for so long, the city's food supplies were likely nearly exhausted. So he advised his father to halt the attack, conserve their strength, and first assess the situation inside Maiqiu before devising a strategy. But the King of Zhao's one-month deadline made Zhao She frantic with anxiety, and he refused to listen to his son's advice.
Zhao She captured prisoners from the state of Qi and tortured them, hoping to extract information about the situation inside Maiqiu City, but the prisoners kept their mouths shut. Zhao Kuo, however, brought food to the prisoners every day, treated them with courtesy, and even let them take grain home. As a result, one prisoner secretly told him, "In truth, the city's food supplies are nearly exhausted, all of it has been used to feed the Qi army. The common people have no food and have started eating each other." Zhao Kuo asked, "Then how much longer can the Qi army hold out?" The prisoner replied, "A few months."
Zhao Kuo had gathered information that his father Zhao She had struggled immensely to obtain, and Zhao She began to see his son in a new light, so he followed his advice, stopped the direct assault, and released all the captives back into the city. After the captives returned, they told the city's residents, "This Zhao army treated us well; not only did they not mistreat us, but they also fed us and let us bring grain back." This caused the city's people to waver, and some began to consider surrendering to the Zhao forces.
The Qi general, seeing that the returning captives were unsettling the people's morale, had them all locked up, which greatly angered the city's residents and soldiers. At this point, following Zhao Kuo's suggestion, Zhao She began ordering his troops to toss grain into the city. Every day, the besieging Zhao army threw grain into the city without saying a word, then returned to camp to rest. A few days later, the Qi army sent people to return the grain, along with a message: "If you want to attack, do it quickly—stop throwing grain into the city."
After the Qi army's scouts returned, Zhao She still did not attack, and after a few more days, he continued to toss grain into the city. Several days later, the Qi army sent another envoy to propose a decisive battle on a chosen day. Zhao Kuo said to his father, "Ignore them." A few days later, they received news that the Qi general defending the city had been killed by the local people, and all the residents of Maiqiu surrendered to the Zhao army.
Zhao Kuo persuaded the people of Maiqiu to surrender without a fight, and when news of this reached the state of Zhao, the king greatly praised him. From a young age, Zhao Kuo loved reading military texts, studying the art of war, discussing military affairs, and even wrote his own books and took on many disciples. When he debated military strategy with his father, Zhao She, he sometimes even got the better of him, yet Zhao She never praised him. Zhao Kuo's mother did not understand this, so Zhao She told her: "War is a matter of life and death, but Zhao Kuo always talks big and treats it too lightly. If the King of Zhao does not put him in command of troops, all will be well; but if he does lead an army, the Zhao forces are sure to be defeated."
The father's words were quickly proven true. In 262 BC, the Zhao army led by Lian Po and the Qin army led by Wang He faced off at Shangdang, with Qin attacking and Zhao defending. Despite several provocations from the Qin forces, Lian Po refused to engage. As the Qin army remained in the field for a long time and their supplies were nearly exhausted, the King of Qin sought advice from Fan Ju. Fan Ju said, "Lian Po is highly experienced. There is only one way to break through the city: make Zhao recall Lian Po."
Fan Ju quickly devised a plan: within a few days, rumors spread throughout the Qin army camp that Lian Po was plotting rebellion. Around the same time, the King of Zhao also heard whispers that Lian Po was old and no longer as capable as before, that the Zhao army was on the verge of being unable to hold out, and that what the Qin forces truly feared was the young and vigorous Zhao Kuo. The King of Zhao grew suspicious of Lian Po and began seeking advice from his ministers.
Lin Xiangru strongly supported Lian Po, saying, "Zhao Kuo only knows how to read his father's military manuals; he has never led troops himself. The battlefield changes in an instant, and with his lack of experience, he cannot bear such a heavy responsibility." King Zhao then consulted the old general Yue Yi, who said, "Lian Po excels at short, decisive assaults, not prolonged standoffs between two armies. Zhao Kuo grew up in the military and has no shortage of combat experience. Moreover, many officers in the Zhao army study military theory under him, so appointing him as general would command widespread respect. Besides, he and his father Zhao She once broke through the formations of a famous Qin general, and the Qin forces hold great fear and respect for the reputation of the father and son."
The King of Zhao, following Yue Yi's advice, summoned Zhao Kuo and asked him if he could defeat the Qin army if sent into battle. Zhao Kuo replied, "If the Qin commander were Bai Qi, I might have to think it over. But since it's Wang He leading the troops, he's barely a match for Lian Po—for me, it's a trivial matter." The King of Zhao then ordered Zhao Kuo to replace Lian Po.
When Zhao Kuo's mother learned that he was to lead the army, she immediately submitted a memorial to the King of Zhao, begging him to revoke the order, saying, "His father repeatedly instructed on his deathbed that he must never be allowed to command troops, for this child treats warfare as a game. If he is made a general, I fear he will only needlessly sacrifice the lives of soldiers." The King of Zhao refused to listen.
Zhao's mother had no choice but to return, urging Zhao Kuo to ask the King of Zhao for rewards and to acquire property for the family. Zhao Kuo was puzzled. His mother explained: "This time you lead the army, taking half of Zhao's troops with you; the King cannot fully trust you. Moreover, the terrain of Shangdang is strategically dangerous, and with such a large force under your command, you could easily declare independence there. As your campaign drags on, someone will inevitably slander you to the King. Furthermore, this expedition concerns the nation's survival—if you lose, the state will fall and families will be destroyed; if you win, your achievements will overshadow the ruler. By requesting rewards for your family and leaving them here, you show the King that you intend to return. In a battle of this scale, victory and defeat are hard to judge, and it all depends on how the outcome is perceived. So, putting the King's mind at ease is more important than anything else."
Zhao Kuo heeded his mother's words. His mother then petitioned the King of Zhao, asking him to promise that regardless of whether Zhao Kuo won or lost the battle, his family would not be implicated. The King of Zhao agreed, and only then did Zhao Kuo lead his troops into battle.
In 260 BCE, Zhao Kuo led his troops to Changping, abolished all the military regulations that Lian Po had established, and issued an order: "Once the Qin army comes to provoke us again, engage them with full force, and after repelling them, pursue the victory to annihilate their entire army."
When news of the Zhao army's change of command reached Qin, Fan Ju realized that the King of Zhao had fallen for the stratagem and immediately replaced the general with Bai Qi. Bai Qi set up an ambush, first engaging the Zhao army in several battles and feigning defeat. Zhao Kuo, unaware of the deception, pursued relentlessly, leading his troops straight into the Qin ambush. The Zhao army was besieged for forty-six days, and when Zhao Kuo led his elite troops in a breakout attempt, he was killed by Qin archers. With their commander dead, over 400,000 Zhao soldiers had no choice but to surrender. In the Battle of Changping, Zhao Kuo cost the lives of more than 400,000 soldiers and doomed the future of the Zhao state, forever earning the reputation in later generations as a general who could only "fight on paper."