Introduction

The popular Vietnamese legend “My Chau – Trong Thuy” has it that after defeating the last Hung King in what is now northern Vietnam, Thuc Phan ascended to the throne under the royal name of An Duong Vuong and renamed the nation from Van Lang to Au Lac, which he ruled from 257 BC to 207 BC. Seeking to establish a new capital, he decided to build a spiral, shell-shaped citadel at Co Loa but found the construction extremely difficult to complete, as every time it was near completion, the citadel would be undone at night by evil spirits. It was only with the assistance of Saint Kim Quy (Golden Turtle) that the citadel was finally completed. In order to help him protect the citadel from enemies, the Saint also offered him one of his claws to make the trigger of a magic crossbow, which was capable of hitting a thousand enemies with just a single shot.

From 217 BC to 207 BC, Trieu Da (Zhao Tuo), who was ruling what is now China's Guangdong and Guangxi provinces, made numerous attempts to invade and conquer Au Lac but never succeeded due to An Duong Vuong's defence tactics, especially with the help of the magic crossbow. In order to find out the secret behind his foe's invincibility, Trieu Da decided to devise a plot. He pretended to negotiate a peace treaty with Au Lac and proposed marriage between An Duong Vuong's daughter, Princess My Chau and his son Trong Thuy (Zhong Shi), to which An Duong Vuong carelessly agreed. It was not before long that Trieu Da learned through My Chau about An Duong Vuong's magic crossbow. He then told his son Trong Thuy to steal and replace the crossbow with a fake one. Now in possession of the magic weapon, Trieu Da launched a new attack on An Duong Vuong and Co Loa soon fell into Trieu Da's hands. An Duong Vuong took My Chau on horseback and fled away to the southern seashore. With the enemy pursuing right behind, An Duong Vuong was desperate and prayed to Saint Kim Quy for help. Replying to his words, the Saint appeared and told him that “The enemy is sitting right behind you!”.