Despite clear signs that the Yuan intended to invade Đại Việt, they initially claimed otherwise. Early in their military campaign, the Yuan sent a letter to Đại Việt, requesting that the kingdom prepare routes, food, and a welcome for the Yuan prince Toghan. Đại Việt ignored the request and, instead, moved troops toward the northern border. General Phạm Ngũ Lão was deployed with additional forces to bolster the defense. Đại Việt’s King reminded Toghan that years earlier, Kublai Khan had declared, “I have forbidden my military commanders to invade your kingdom.” In response, Toghan insisted that his forces were targeting Champa, not Đại Việt.
As the Yuan forces progressed deeper into Đại Việt, they were persistently attacked by guerrilla fighters. Several notable incidents were recorded, including one along the Thương River. A Yuan vanguard stopped at the riverbank in search of ships to cross. On the opposite shore, two beautiful girls operating a shop offered to cross the river with Yuan commanders. The locals held a party to entertain the Yuan soldiers as they rested, unaware that young men from the village had secretly drilled holes in their boats, temporarily plugging them to prevent water from entering. That night, as the Yuan commanders boarded with the girls, the young men removed the plugs, causing the boats to sink. The commanders drowned, and the now leaderless Yuan forces were swiftly attacked and defeated.
“Behead Me First!”
In late 1284, after suffering a defeat at Chi Lăng, Prince Hưng Đạo retreated to Vạn Kiếp. The King, worried about the strength of the Yuan forces, summoned him to Hải Dương and asked:
- “With the enemy so strong, should we surrender to avoid bloodshed and the destruction of our country?”
Prince Hưng Đạo responded passionately:
- “I understand your concern for our homeland, but what would become of the dynasty’s sanctuary and our society if we submit? If you wish to surrender, then behead me first!”
Reassured by these brave words, the King allowed Hưng Đạo to return to Vạn Kiếp to oversee military preparations. With unwavering determination, Hưng Đạo composed a stirring proclamation to inspire his soldiers, a work now regarded as one of the gems of Vietnamese literature. The proclamation expresses deep anguish over the suffering faced by their homeland by the Yuan invaders and urges military leaders to recognize the dire consequences of submission, which would lead to the loss of their land, families, and honor. With passion, it calls for unity and preparation against the Mongols, stressing the importance of military training and readiness. After that, many soldiers and civilians alike showed their commitment by tattooing “Kill the Yuan-Mongols” on their arms, uniting everyone in the fight for their homeland.
The Diên Hồng Convention
In feudal society, elders were highly respected and regarded as the representatives of their communities. The Retired King organized the Diên Hồng convention, inviting the oldest men from across the country to discuss the nation’s affairs. This marked the first occasion where these elder statesmen gathered to converse with their Retired King, despite their limited knowledge of politics and military matters. Many of them were so frail that they needed to be carried by the young men of their villages, but their spirits remained unyielding. The Retired King hosted the banquet himself and posed a critical question: should they fight or submit?
To his surprise, every elder raised their fists in unison and declared:
- FIGHT! FIGHT!
The hall resonated with the thunderous voices of determined men, as if they were one collective force. Following the convention, these elders became crucial conduits for communicating government policies back to their villages.
Historian Ngô Sĩ Liên remarked that the war posed a significant challenge for the nation. While the Retired King, the King, and the court had already devised strategies for the conflict, the purpose of the convention was to gauge civilian sentiment through their representatives and to galvanize public support.
From that moment on, the Diên Hồng convention symbolized the unity between the government and the populace. Meanwhile, Toghan’s forces had reached Ung Châu, and the Yuan troops led by Naxirut Din from Yunnan were poised to cross the border. In response, the Vietnamese civilians began stockpiling food, weapons, and troops as ordered by the government.
By the end of January 1285, Toghan and Ariq Qaya arrived at the Đại Việt border with their forces. The Vietnamese troops were prepared, and the Emperor sent Toghan a strategic letter designed to feign fear:
“I cannot see your illustrious presence, but I am pleased to receive a message from the Mandate of Heaven, which instructs me not to attack your country. However, I am alarmed to learn of numerous barracks in Ung Châu. Please reassess our loyalty and pardon any missteps.”
In reply, Toghan deceitfully claimed, “We are preparing to attack Champa, not Annam [Đại Việt].” Shortly thereafter, the first battles commenced, marking the official beginning of the war.
See also: Tran dynasty: the dynasty that defeated the Mongols 3 times
