In the Warring States period, there was a man of the state of Chao named Lin Hsiang-ju (蔺相如); he was employed by the king of Chao and handled the affairs of the land.
The minor state of Chao had for generations possessed an unusual jade disc, made from the Ho jewel. The king of the powerful state of Ch’in heard of the disc and offered to trade fifteen cities for it. Chao, a militarily weak state, could not refuse and sent Lin Hsiang-ju with the disc to the Ch’in King.
Hsiang-ju, however, perceived that the king had no real intention of ceding fifteen cities and said to the king, “The jewel has a flaw. if you will give it to me, I will show you where it is.”
Once he had the jewel back in his hands, he backed himself up against a pillar and threatened to smash the disc against the pillar if the king did not follow proper ritual, fast and purify himself for five days, and honestly offer the fifteen cities. The king promised to do so.
While waiting for the king to complete five days of preparation, Hsiang-ju sent one of his attendants dressed in disguise back to Chao via a secret route with the disc.
On discovering this, the king of Ch’in reluctantly agree with Hsiang-ju that killing him would not bring back the disc and so released him.
完璧归赵, From Shih-chi, Cha81, Translated by Yang and Yang 1979