Rach Gam Xoai Mut Battle Site

Twenty thousand men stood against 50,000 men and 300 war boats. The smaller side was not even half as large. Yet after a single night on the Tiền River, that great fleet had no room left to turn.

The reason lies in that same stretch of river, and in a river mouth called Trà Tân. From there, a huge fleet of war boats sailed downstream, toward a stretch of river that no one aboard saw as a battlefield.

The story begins in southern Vietnam at the end of the 18th century. Nguyễn Ánh was then struggling to hold the land of Gia Định. He would later become Emperor Gia Long, the founder of the Nguyễn dynasty. He went to the kingdom of Siam for help. The Siamese king, the first of the Chakri line, agreed. In July 1784, the king sent two of his nephews, Chiêu Tăng and Chiêu Sương. They led about 50,000 troops and 300 war boats. By the end of that year they had pushed as far as Trà Tân, on the north side of the Tiền River. Wherever the Siamese army went, the people of the river country suffered from looting.

Early in January 1785, Nguyễn Huệ led his war boats across the sea into Gia Định. He set up his headquarters at Mỹ Tho. His army numbered only about 20,000 men. He did not attack head on. Instead, he let the river fight on his side.

He chose the stretch of river that runs from Rạch Gầm down to Xoài Mút. It was about 7 kilometers long. The riverbed was more than 1 kilometer wide, room enough for a whole large fleet to sail in. Thới Sơn Islet sat in the middle of the stream. In those days few houses stood on either bank, and the trees and brush grew thick, ideal for hiding men. The Tây Sơn army and the local people quietly laid out their positions. The Tây Sơn were three brothers who led an uprising from 1771 and for a time ruled Vietnam. Foot soldiers and cannon hid along the banks and on the islet. The boats were split into several squadrons and tucked away out of sight.

Then Nguyễn Huệ sent a prisoner of war from Chân Lạp as his envoy. Chân Lạp was the old Vietnamese name for the Khmer kingdom of Cambodia. The envoy carried plenty of gold, silver and brocade to the Siamese camp, with an offer of peace. Chiêu Tăng believed that the Tây Sơn army was off guard, so he planned a surprise attack.

On the night of January 19, 1785, running into the dawn of January 20, the Siamese fleet left Trà Tân. That river mouth lies about 15 kilometers upstream from Rạch Gầm. The boats sailed downstream toward Mỹ Tho. The water was still dark. Around the fifth watch of the night, just before daybreak, the whole fleet had passed Rạch Gầm and slipped into the middle of the stretch.

At that moment, two hidden squadrons shot out at once, one from Rạch Gầm and one from Xoài Mút. They blocked both the head and the tail of the fleet. From both banks and from Thới Sơn Islet, cannon fired together into the middle of the formation. The squadrons waiting in ambush charged straight in and cut the Siamese fleet into pieces. Blocked in front, blocked behind, with guns lining both banks, the great fleet had no room left to turn.

Nearly 40,000 Siamese troops were killed, along with thousands of the men fighting for Nguyễn Ánh. All of the more than 300 war boats were sunk or destroyed. Chiêu Tăng and Chiêu Sương escaped to the north bank with a small band of men. They went overland through Chân Lạp and did not reach Bangkok until March. The army had set out 50,000 strong. Only a little more than 10,000 came home. Nguyễn Ánh had prepared his escape route in advance. With just over 800 followers, he fled to take refuge in Siam. Later generations called this the largest naval battle in Vietnam in the 18th century.

Today, on the north bank of the Tiền River, at the mouth of Rạch Gầm, there is a historic site. It is the Rạch Gầm Xoài Mút Victory Site. It lies in Đông hamlet, Kim Sơn commune. The site is in Đồng Tháp province, about 12 kilometers from Mỹ Tho. At the end of 2014, it was designated a special national monument.

The first thing to catch the eye is a monument cast in bronze. It weighs 20 tons and stands 8 meters tall, on a concrete pedestal 10 meters high. Nguyễn Huệ draws his sword and gazes straight out over the Tiền River. Two figures below him stand for the Tây Sơn fighters and the people of Định Tường. Together they say that the victory belonged to a great many people.

At the foot of the monument is Gallery One, built in the shape of a war boat. It covers 135 square meters. It holds artifacts and weapons from both the Tây Sơn and the Siamese armies, some raised from this very riverbed. Among them is an anchor made of sao wood. It is 3.39 meters tall and weighs more than 200 kilograms. It was found in 1990 in the bed of the Tiền River, near the river mouth at Trà Tân. Carbon-14 testing shows that the wood is about 200 years old. Still, no one can say for certain which boat it fell from.

Gallery Two covers 132 square meters and is given over entirely to the course of the battle. Its scale model and maps let visitors follow each step of that night, from the moment the fleet left Trà Tân until both ends of the river closed. Nearby, a jetty reaches out over the Tiền River. The last stop on the visitor route is an old southern house of three bays, built in 1927. It tells of the lives of the families of Định Tường beside this river.

In January 2025, exactly 240 years after the battle, the site held a festival. There was an arts program called Linh thiêng tiếng sóng Rạch Gầm, which means the sacred sound of the waves at Rạch Gầm. There was a contest in arranging trays of five fruits, and matches in traditional martial arts.

At first light, from the end of the jetty, the Tiền River spreads wide, and Thới Sơn Islet lies like a shadow in the distance. It is close to the hour when the Siamese fleet slipped into the trap long ago. Back inside the gallery stands the anchor of sao wood. It once lay in the bed of this river. Now it rests on the bank, right beside the same water.