page_title: Lý–Song War
section_title: Later stages
hierarchical_section_title: Lý–Song War / Conflict / Later stages
context_page_description: The Lý–Song War was a significant war fought between the Lý dynasty of Đại Việt and the Song dynasty of China between 1075 and 1077. The war began in 1075 when the Lý emperor ordered a preemptive invasion of the Song dynasty using more than 100,000 soldiers, where Đại Việt's forces defeated the Song army and razed the city of Yongzhou to the ground after a forty-two day siege. In response, in 1076 the Song led an army of over 300,000 to invade Đại Việt and by 1077 nearly reached Thăng Long, the capital of Đại Việt, before being halted by general Lý Thường Kiệt at the Nhu Nguyệt River in modern Bắc Ninh Province. After a long battle at the river with high casualties on both sides, Lý Thường Kiệt offered peace to the Song, and the Song commander Guo Kui agreed to withdraw his troops, ending the war.
context_section_description: Lý Thường Kiệt had fought a war with the Chams in 1069, and in 1076, the Song called upon their vassal states the Khmer Empire and Champa to go to war again against the Lý. At the same time, the Song commander Guo Kui (1022–1088) led the combined Song force of approximately 300,000 men against Lý, who were at the time simultaneously defending against incursions from the Khmer Empire and Champa. The Song quickly regained Quảng Nguyên prefecture and in the process captured the resistance leader Lưu Ký, the chieftain of Quảng Nguyên that had attacked Yongzhou in 1075. By 1077, the Song had destroyed two other Vietnamese armies and marched towards their capital at Thăng Long (modern Hanoi). Song forces were halted at the Nhu Nguyệt River (in modern Bắc Ninh Province), where Lý Thường Kiệt had built a defense system by placing spikes under the Như Nguyệt riverbed before tricking Song troops into the death trap, killing more than 1,000 Chinese soldiers and sailors. In avoiding this strong defense system, the commander of the Song army, Guo Kui decided to change the army's direction towards the nearby region of Phú Lương, where they then defeated Lý Thường Kiệt's forces in a major battle. As the Song forces took the offensive, while the Lý Dynasty had to strenuously hold on to their costly defensive front, Lý Thường Kiệt tried to boost the morale of his soldiers by citing a poem before his army named "Nam quốc sơn hà". However, Song forces eventually broke through his defense line and their cavalry advanced to within several kilometers of the capital city. The Vietnamese counterattacked and pushed Song forces back across the river while their coastal defenses distracted the Song navy. Lý Thường Kiệt also launched an offensive, but lost two Lý princes in the fighting at Kháo Túc River. According to Chinese sources, "tropical climate and rampant disease" severely weakened Song's military forces while the Lý court feared the result of a prolonged war so close to the capital.
caption: Song forces reached Nhu Nguyệt River in Bắc Ninh Province (highlighted in red) near the capital of Thăng Long