The Mongol Invasions of Vietnam

Well hello again gentle readers and welcome to the first post of the 2009 edition of Tactica Guerilla. I have had a good holiday, but now it is time to get off my lazy backside and update, as I am sure you all are anxious for.

Anyway today’s topic is a new one for me, the Mongol invasions of what is now Vietnam. Most people would be familiar with the failed invasions of Japan and the myth of the kami kaze (Divine Wind) but what about South East Asia? That is what I intend to cover with this issue.

In 1253 AD the Mongol Empire, among the largest and most militarily successful states in history, entered South East Asia through the conquest of the kingdom of Nanzhao (in modern Yunnan). This was all part of Mongol grand strategy, as the annexation of Nanzhao provided the Mongols with the means to outflank the Chinese Southern Song dynasty. In 1257 the Mongols made their formal introduction to the kingdoms of modern Vietnam when Uriyangqadai (the son of Subadai, among the Mongol’s greatest leaders) led an invasion force through the Kingdom of Dai Viet as part of an assault upon the Song.

The ruling Tran dynasty was rendered helpless by panic, and fled out to sea to take refuge on a distant island. The Viet people, however, waged a guerilla war, taking to the mountains and burning their villages to prevent the Mongols from being able to live off the land. Uriyangqadai, however, was not interested in conquering Dai Viet, and contented himself with the occupation of the capital, Thang Long (modern Hanoi), and the formal submission of the Tran authorities. The Mongols left the following year, in 1258, but this was but a taste of things to come.

Over the course of the following years the situation would change dramatically. In 1260 the Mongols were revitalized by the leadership of the dynamic Qubilai, who soon demanded the submission of the submission of both Vietnamese kingdoms (Dai Viet and Champa), who were forced to accept in the face of overwhelming Mongol might. However this was soon shattered. The newly proclaimed Yuan Empire (1271) was defied by two unlikely states: the Hojo Regency of Japan (1274 and 1281) and the Burmese Kingdom of Bagan (1277). The defeats at both their hands were a humiliation and broke the myth of Mongol invincibility. This encouraged the kings of Dai Viet and Champa and set the stage for further events.

In 1281, even as Yuan armies prepared for the second invasion of Japan, Qubilai Qa’an demanded personal tribute and submission from Champa. The elderly Indravarman V refused and fled the kingdom like the Tran kings of the north for an island. The Crown Prince, Che Man, took charge of the defense. Even as Yuan forces under Sodu, a leading marshal, landed at the capital of Vijaya, the Chams withdrew into the mountains. When the Mongols followed Che Man surprised them with a fierce guerilla war.

Like the Dai Viet in 1257 they burned their own villages, but also used their own techniques. One in particular was the heavy usage of crossbow cavalry and of siege crossbows mounted on elephants. In frustration, Qubilai ordered that Dai Viet to submit to the usage of their country as a highway for a second Yuan army to enter Champa. But the Tran dynasty refused.

The first real invasion of Dai Viet was undertaken in 1284. Hoping that a quick strike would eliminate Dai Viet resistance Qubilai had sent an army south under his son Prince Torghon with neither clear objectives (either military or political) or a supply train. Both of these elements would come back to haunt the invaders. As before Thang Long fell before the whirlwind, but it reaped no benefits. The entire leadership structure of the Dai Viet state had fled with the Tran monarchy.

Military affairs were left in the able hands of General Tran Hung Dao, who made the Yuan occupation a living nightmare. A combination of scorched earth, endless river raids, and the onset of hot heavy rains finally drove the Yuan out. In the last phase of the occupation the general Sodu, marching north from Champa and unaware of the withdrawal, was slain in pitched battle at Siming in 1285. The Mongols had been beaten back.

But Qubilai would not accept this. Now more obsessed with Vietnam then anything else, Qubilai put on hold plans for a third invasion of Japan to conquer Dai Viet and Champa completely. In 1286 Yuan armies re-entered Dai Viet. Having seemingly learned the lessons of the previous invasion they advanced more slowly and methodically, using combined land and sea forces to keep in supply while reducing the border forts. In 1287 Prince Torghon captured Thang Long, but as before the Tran monarchy and their court had escaped. When the Dai Viet struck back along the flood plains of the Red River Torghon withdrew.

He returned in 1288, during the hot season. Tran Hung Dao took advantage of the Yuan leadership’s ineptitude to strike back on land and sea. With the fall of the fortress of Dai Than to Vietnamese guerillas and the loss of the entire supply fleet at Van Don the Yuan chose to withdraw a second time. But Tran Hung Dao was not willing to allow them to leave. At the estuary of the Bach Dang River, near modern Haiphong, he saw his chance. Hoping to repeat the success of Ngo Quyen against the Southern Han in 939, Tran had his men line the bed of the river with short wooden poles topped with iron points. He then sent his numerically inferior navy to lure the Yuan ships into the river mouth at high tide.

When the tide receded the ships became stuck and the Dai Viet forces swarmed over them, massacring the Yuan forces. Torghon retreated in disgrace and the Mongols would not return. Dai Viet and Champa would both resume sending tribute to Dadu, the Yuan capital, but from a position of strength instead of weakness.