In the northern part of Viet Nam in a region named Van Xuan, there is a river called Bach Dang. This river is small in size, but it has played a big role throughout the history of the country, even before it became known as Viet Nam. At high tide, the river swells up, and the passageways from the river to the sea overflow with water. When the tide falls, the water subsides, and the entrances to the river appear again.
In 938, barbarous and powerful invaders from the northern land of Nam Han attempted to overtake the Van Xuan region of the Viet country. General Ngo Quyen devised a plan that demonstrated his brilliance in military strategy and tactics. He instructed his soldiers to construct wooden sticks with sharp metal points. At low tide when the waters were shallow, the soldiers planted these sticks into the bottom of the Bach Dang river with the metal points standing straight up.
At high tide, when the river had risen far enough to cover the tops of the sticks, General Ngo Quyen engaged the enemy in a battle on the seas. As the tide began to fall, he lured the enemy into the mouth of the river. Before the water dropped too low, the general quickly withdrew his troops. As the water continued to drop, the invaders' ships were torn to pieces by the wooden sticks that were now exposed in low tide. The enemy had been vanquished, and the Viet people were victorious.
In 1283, the Mongol king Hot Tat Liet sent his son, Prince Thoat Hoan, and an army of 500,000 soldiers to invade the land of the Viet, known during this time as Dai Viet and ruled by the Tran Dynasty.
The Mongolian army outnumbered the Viet soldiers, and were cruel in battle. After a year of fighting, Emperor Tran was ready to surrender. In 1284, Emperor Tran Nhan Tong called all the elder men in the country to come to the capital to advise him on whether or not to continue fighting. One of the most courageous and greatest heroes in Viet history, General Tran Quoc Tuan, was determined to fight against the invasion. Inspired by his patriotism and his leadership, the Viet people united against the Mongolians and defeated them within six months.
The Mongolians did not stay away for long, however. In 1287, Prince Thoat Hoan led an army of 300,000 soldiers back into Dai Viet in a second attempt to conquer the country. After a year of fighting, General Tran Quoc Tuan recalled the tactic that had saved the country once before. He instructed his soldiers to plant wooden spears into the Bach Dang river, just as had been done 350 years ago. The Mongolian army and its 400 battle ships were destroyed. Peace returned to the Viet people, and the Bach Dang river became famous in history.