In the final years of the Warring States period, Qin's power swelled as its mighty army crushed the states of Han and Zhao, then turned toward Yan. The Crown Prince Dan of Yan, desperate to turn the tide, began plotting to assassinate King Zheng of Qin (the future First Emperor).
Prince Dan of Yan, once held hostage in the Qin capital Xianyang, was treated with contempt by the King of Qin. Desperate to return home, he pleaded for release, but the king scoffed, "You may leave only when crows turn white and horses grow horns." Legend has it that Prince Dan looked up to heaven and sighed, and miraculously, the crows' heads turned white and horses sprouted horns. Forced to honor his word, the king reluctantly let him go.
The King of Qin had no intention of truly releasing Crown Prince Dan. He set a trap on the bridge Dan had to cross, planning to kill him, but the mechanism failed to trigger, allowing Dan to cross safely. Reaching the border gate late at night, Dan found it locked; he imitated a rooster's crow, prompting all the roosters to crow in unison, the gate opened, and he escaped back to the State of Yan.
When Prince Dan of Yan was searching for the right person, a man named Tian Guang introduced him to Jing Ke, a warrior who had fled from the State of Wei to Yan. Jing Ke was skilled in both civil and martial arts, especially swordsmanship, making him the ideal candidate to assassinate the King of Qin. Prince Dan honored Jing Ke as his highest advisor, showering him with wealth and luxury, and Jing Ke solemnly pledged to undertake the mission.
To get close enough to assassinate the King of Qin, Crown Prince Dan of Yan prepared two items the king desperately wanted: the head of Fan Yuqi, a renegade general from Qin who had fled to Yan and whom the king loathed, and a map of the Du'ang region in Yan, symbolizing Yan's willingness to cede that territory. After Jing Ke explained the plan, Fan willingly took his own life.
These two items were stored in separate boxes. The dagger used to assassinate the King of Qin—a short sword—was hidden inside the rolled-up map. The dagger had been soaked in poison, so even a tiny scratch would prove fatal. Additionally, Crown Prince Dan assigned Jing Ke an assistant, a man named Qin Wuyang.
On the day of departure, Crown Prince Dan, dressed in white mourning garments, led a group of trusted officials to bid farewell to Jing Ke at the Yi River. After singing a solemn song, Jing Ke climbed into his carriage and headed west without looking back.
When Jing Ke arrived in Xianyang, he leaked news of the two precious caskets he had brought. The King of Qin was overjoyed and, selecting an auspicious day, received Jing Ke and his companions with great ceremony as envoys from the state of Yan.
On the appointed day, the King of Qin donned his court robes and prepared the grandest ceremony in the Xianyang Palace. Amidst solemn and majestic atmosphere, Jing Ke walked ahead, holding the casket containing Fan Yuqi's head, while Qin Wuyang followed behind, carrying the casket with the map.
Qin Wuyang's hands trembled and his face turned pale as he climbed the steps. The civil and military officials nearby found this very strange. Jing Ke immediately noticed the situation. He turned back and smiled at Qin Wuyang to ease his tension, then finished climbing the steps, knelt down, and apologized to the King of Qin, saying:
"We are barbarians from the north who have never seen a wealthy and noble Son of Heaven, so we are very afraid. We beg Your Majesty to forgive him and allow him to complete his mission before you." The King of Qin said to Jing Ke nonchalantly, "Rise, and show me the map that Qin Wuyang is holding."
Jing Ke opened the casket, took out the map, and presented it to the King of Qin with both hands. The king slowly unrolled the scroll, examining it closely. As the map reached its end, a gleaming dagger was suddenly revealed. Seizing the moment, Jing Ke grabbed the king's sleeve with his left hand and raised the dagger with his right, ready to strike.
Unfortunately, the dagger missed the King of Qin. The king frantically tried to draw his sword to defend himself, but it was stuck fast. Terrified, he fled around a pillar, with Jing Ke in hot pursuit. The civil and military officials in the court were thrown into chaos, unsure of what to do. The guards were all on the steps, and by law, without the king's command, they could not enter the hall.
In that critical moment, the king's imperial physician suddenly hurled his medicine bag at Jing Ke, shouting to the king, "Push the sword behind your back and draw it quickly!" The king snapped to his senses, swiftly pulled the sword free, and slashed down, severing Jing Ke's left leg. As Jing Ke collapsed, he hurled his dagger at the king but missed, and was immediately swarmed and killed by the guards.
This is the story of Jing Ke's assassination attempt on the King of Qin. Later, people used "the map unrolled and the dagger revealed" to describe how, when things reach the end, the truth or true intention is ultimately fully exposed.
Source: *Strategies of the Warring States*, Chapter "Strategies of Yan III"
Meaning of the Idiom: Later, the Chinese idiom "图穷匕见" came to describe how when things reach the end, the truth or true intention is ultimately fully exposed.