During the Southern and Northern Dynasties (420-589), Princess Lechang of the State of Chen was renowned for her beauty and intelligence. She and her husband, Xu Deyan, shared a deep love. Fearing an imminent invasion by the Sui Dynasty, they foresaw chaos and separation.
To maintain a promise of reunion, they broke a bronze mirror—a symbol of marital unity—into two halves, each keeping one piece. They agreed to search for each other at the Lantern Festival fair on the 15th day of the first lunar year, hoping to reunite and join the mirror halves.
Their fears materialized. Amidst the war, the princess was separated from her husband and taken as a concubine by the powerful minister Yang Su. The following year, Xu Deyan went to the fair with his half of the mirror. There, he encountered a servant selling the other half. Recognizing it, he learned of his wife's plight and was overcome with grief. On her mirror half, he inscribed a poignant poem expressing his longing.
When the servant returned the inscribed half to Princess Lechang, she wept for days, knowing her husband was alive yet believing they were forever parted. Minister Yang Su, discovering their story, was moved by their enduring love. Realizing he could not win her heart, he summoned Xu Deyan and allowed the couple to reunite.
This tale gave rise to the idiom "A broken mirror joined together," symbolizing the joyful reunion of a separated couple.