Siege of Ansi fortress (645 AD): battle between Goguryeo and Tang forces in Ansi (Liaodong, China)
The siege of Ansi halted Tang Emperor Taizong's first major campaign against Goguryeo, demonstrating the kingdom's capacity to repel a superior imperial force.
Key Facts
- Siege duration
- ~3 months (20 June – 18 September 645)
- Goguryeo relief force defeated
- 150,000 troops
- Goguryeo casualties
- Over 20,000 killed
- Outcome
- Tang forces retreated without capturing Ansi
- Tang retreat cause
- Collapsed rampart, winter, reinforcements, lack of supplies
By the Numbers
Location
Cause → Event → Consequence
Tang Emperor Taizong launched the First Goguryeo–Tang War campaign seeking to conquer Goguryeo. Tang forces advanced into the Liaodong Peninsula and, after defeating a Goguryeo relief army of 150,000, moved to besiege the fortress of Ansi, which controlled a key strategic position in the region.
From 20 June to 18 September 645, Tang forces besieged the Ansi fortress. After roughly two months, they constructed a large earthen rampart intended to overtop the walls, but a section collapsed and was seized by the defenders. Combined with the onset of winter, arriving Goguryeo reinforcements, and critical supply shortages, the Tang army was compelled to abandon the siege.
The failure to capture Ansi forced the Tang army into retreat, ending the first major imperial campaign against Goguryeo without a decisive victory. Over 20,000 Goguryeo troops perished during the siege, yet the fortress held, checking Tang expansion into the Korean peninsula and prolonging the Goguryeo–Tang conflict.
Belligerents & Mobilization Analysis
Side A
1 belligerent
Side B
1 belligerent