Battle of Ngọc Hồi-Đống Đa

Battle of Ngọc Hồi-Đống Đa (Trận Ngọc Hồi - Đống Đa; 清軍入越戰爭) was fought between Tây-Sơn (Vietnamese) and Qing China in Ngọc Hồi and Đống Đa northern Vietnam from 1788 to 1789. It is considered one of the greatest victories in Vietnamese military history.

Background
For most of her history, Vietnamese kings sometimes recognized the Chinese Emperor as their feudal lord, while ruling independently in their own land. This had been the case throughout the reign of the Later Lê Dynasty.

However, the Tây Sơn uprising broke out in 1771, and the Lê Dynasty was overthrown by Tây Sơn army in 1787. The last emperor, Lê Chiêu Thống, fled to China and appealed to Emperor Qianlong for help. In 1788, a large Qing army was sent to Vietnam, in order to restore Lê Chiêu Thống to the throne.

Battle
Sun Shiyi, the Viceroy of Liangguang, was appointed as commander in chief. According to Draft History of Qing, the total number of Chinese armies was about 200,000-290,000 (Qing Dynasty said 15,000 troops, including soldiers and porters) which recruited from Guangdong, Guangxi, Yunnan and Guizhou.

In October, the Qing armies began their invasion. On November 19, Thăng Long (mordern Hanoi) was captured by Qing armies. The Vietnamese retreated to Tam Điệp mountains; from there they sent a messenger to Phú Xuân (modern Huế), appealing to Nguyễn Huệ for help.

Nguyễn Huệ was proclaimed the Quang Trung Emperor, and recruited 100,000 volunteers in Nghệ An Province. Then he gathered his forces in the countryside around Thăng Long which had been taken by the Qing armies. He launched a surprise attack against the Qing forces while they were celebrating the Chinese New Year festival of the year 1789. Most of Chinese soldiers were unprepared, so were disastrously defeated by the Tây Sơn army in Ngọc Hồi and Đống Đa (part of modern Hanoi). Chinese generals Xu Shiheng, Shang Weisheng, Zhang Chaolong and Cen Yidong were killed in action. Nguyễn Huệ recaptured Thăng Long, and Sun Shiyi and Lê Chiêu Tông fled back to China. Many Chinese soldiers and porters drowned crossing the Red River.

Aftermath
Although Nguyễn Huệ won this battle, he eventually submitted himself as vassal of Qing China and agreed to pay tribute annually. Battle of Ngọc Hồi-Đống Đa was considered one of the greatest military victories by Vietnamese people, but was also considered one of "Ten Great Campaigns" during the reign of the Qianlong Emperor by the Chinese.