The Legend of Mỵ Châu and Trọng Thủy

King An Dương Vương ascended the throne and renamed the kingdom to Âu Lạc. After building the Cổ Loa citadel, he was granted a claw from the Golden Turtle God to use as a trigger, which he entrusted to Cao Lỗ to craft into a magical crossbow for defending the citadel. At that time, Triệu Đà led his army to invade Âu Lạc, but with the magical crossbow in hand, King An Dương Vương could fire a hundred arrows with perfect accuracy, each shot capable of killing thousands of enemy soldiers. The enemy fell like grass before a scythe, and a furious Triệu Đà was forced to retreat to Vũ Ninh, where he sought a way to destroy the crossbow.

Triệu Đà, knowing that An Dương Vương had a daughter named Mị Châu, sent his son, Trọng Thủy, to pretend to propose marriage and establish peaceful relations. Mị Châu, captivated by Trọng Thủy’s handsome and noble appearance, fell in love with him. An Dương Vương then gave Mị Châu in marriage to Trọng Thủy. Trọng Thủy, coaxing Mị Châu, asked to see the magical crossbow. Mị Châu, unaware of the danger, went to retrieve it from where her father kept it and showed it to Trọng Thủy. He secretly broke the trigger and replaced it with a fake one, then pretended to wish to return home to visit his parents. Before leaving, Trọng Thủy told Mị Châu, “Though we are husband and wife, if our two countries fall into conflict, how will we find each other?” Mị Châu replied, “I have a goose feathered blanket that I always carry with me. As I travel, I will scatter the feathers along the road where the path divides to leave a trail for you to follow.”

Trọng Thủy returned and informed Triệu Đà. Triệu Đà then led his army to invade Âu Lạc. King An Dương Vương took out the magical crossbow to defend the kingdom, but it was broken. Triệu Đà’s army pressed forward, and King An Dương Vương fled south with Mị Châu. Trọng Thủy followed the trail of goose feathers left behind by Mị Châu. When King An Dương Vương reached the coast, he called upon the Golden Turtle for help. The turtle surfaced and scolded him, saying, "The one sitting behind you on the horse is the enemy, why haven’t you killed her?". Realizing the betrayal, King An Dương Vương drew his sword to slay Mị Châu. In desperation, Mị Châu pleaded, "I have remained faithful and loyal, but I was deceived. Let me turn into pearls to wash away this shame." Despite her plea, King An Dương Vương still beheaded Mị Châu. Her blood flowed into the sea, and oysters swallowed it, turning into pearls.

Trọng Thủy arrived to find Mị Châu already dead. Grieving deeply, he wept and carried her body back to Cổ Loa to bury her, where she transformed into a jade stone. Consumed by sorrow and regret, Trọng Thủy returned to the spot where Mị Châu used to bathe and adorn herself, unable to overcome his grief. In the end, he threw himself into the well and died. Later, people discovered pearls in the East Sea, and when they washed them in the water from that well, the pearls became even more lustrous.