Siege of Songping

Siege of Songping (863)
	Part of Tang-Nanzhao war in Annan
Date	Spring 863; (14 January – 1 March, 1 month 15 days)
Location	Songping, Protectorate of Annan (present-day Hanoi, Vietnam)21°01′42″N 105°51′15″E / 21.02833°N 105.85417°E
Result	Nanzhao victory Temporary Nanzhao occupation of the Red River Delta; Weakening of the Tang dynasty;
Belligerents
Nanzhao	Tang dynasty
Commanders and leaders
Duan Qiuqian; Yang Sijin; Chu Đạo Cổ	Cai Xi †
Strength
50,000	unknown
Casualties and losses
unknown	unknown
	class=notpageimage\| Location of the battle

The siege of Songping or the siege of Hanoi was the pivotal part of Nanzhao's great offensive in 863. Nanzhao was in alliance with local tribal rebels, against the Tang dynasty who was currently in control of the Red River Delta in modern-day northern Vietnam. The siege took place in Songping (modern-day Hanoi), capital of Tang's frontier Protectorate General to Pacify the South in early 863 during the reign of Emperor Yizong. It was the fourth time since 858 that Songping was attacked by Nanzhao forces

The siege was one of the most important and tragic events in the history of Vietnam before the tenth century. With 50,000 men from its main army and other tribal mercenaries combined, the Yunnanese approached Songping and issued an ultimatum to surrender or die. They laid siege on the city from mid-January until its fall on 1 March, resulting in military disaster and the retreat of Tang forces out of the region in 2 years.