page_title: Goguryeo–Tang War
section_title: Conflict in 645
hierarchical_section_title: Goguryeo–Tang War / Course of the war / Conflict in 645
caption_attribution_description: English: Map showing actions in the First Goguryeo-Tang War.
context_page_description: The Goguryeo–Tang War occurred from 645 to 668 and was fought between the Goguryeo Kingdom and Tang Dynasty. During the course of the war, the two sides allied with various other states. Goguryeo successfully repulsed the invading Tang armies during the first Tang invasions of 645-648. After conquering Baekje in 660, Tang and Silla armies invaded Goguryeo from the north and south in 661, but were forced to withdraw in 662. In 666, Yeon Gaesomun died and Goguryeo became plagued by violent dissension, numerous defections, and widespread demoralization. The Tang–Silla alliance mounted a fresh invasion in the following year, aided by the defector Yeon Namsaeng. In late 668, exhausted from numerous military attacks and suffering from internal political chaos, the kingdom of Goguryeo and the remnants of Baekje army succumbed to the numerically superior armies of the Tang Dynasty and Silla.
  The war marked the end of the Three Kingdoms of Korea period which had lasted since 57 BCE. It also triggered the Silla–Tang War during which the Silla Kingdom and the Tang Empire fought over the spoils they had gained.
context_section_description: Emperor Taizong of Tang used Yeon Gaesomun's murder of the Goguryeo king as the pretext for his campaign and started preparations for an invasion force in 644. General Li Shiji commanded an army of 60,000 Tang soldiers and an undisclosed number of tribal forces which gathered at Youzhou. Emperor Taizong commanded an armored cavalry of 10,000 strong. His cavalry eventually met up and joined General Li Shiji's army during the expedition. A fleet of 500 ships also transported an additional 40,000 conscripted soldiers and 3,000 military gentlemen (volunteers from the elite of Chang'an and Luoyang). This fleet sailed from the Liaodong Peninsula to the Korean Peninsula.
  In April 645, General Li Shiji's army departed from Yincheng (present-day Chaoyang). On 1 May, they crossed the Liao River into Goguryeo territory.  On 16 May, they laid siege to Gaimou (Kaemo), which fell after only 11 days, capturing 20,000 people and confiscating 100,000 shi (6 million liter) of grain.
  Afterwards, General Li Shiji's army advanced to Liaodong (Ryotong). On 7 June, they crushed a Goguryeo army of 40,000 troops strong, which had been sent to the city to relieve the city from the Tang siege. A few days later, Emperor Taizong's cavalry arrived at Liaodong. On 16 June, the Tang army successfully set Liaodong ablaze with incendiary projectiles and breached its defensive walls, resulting in the fall of Liaodong to the Tang forces.
  The Tang army marched further to Baiyan (Paekam) and arrived there on 27 June. However, the Goguryeo commanders surrendered the city to the Tang army. Afterwards, Emperor Taizong ordered that the city must not be looted and its citizens must not be enslaved.
  On 18 July, the Tang army arrived at Ansi Fortress. A Goguryeo army, including Mohe troops, were sent to relieve the city. The reinforcing Goguryeo army totaled 150,000 troops. However, Emperor Taizong sent General Li Shiji with 15,000 troops to lure the Goguryeo forces. Meanwhile, another Tang force would secretly flank the enemy troops from behind. On 20 July, the two sides met at the Battle of Jupilsan and the Tang army came out victorious. Most of the Goguryeo troops dispersed after their defeat. The remaining Goguryeo troops fled to a nearby hill, but they surrendered the next day after a Tang encirclement. The Tang forces took 36,800 troops captive. Of these prisoners, the Tang forces sent 3500 officers and chieftains to China, executed 3300 Mohe troops, and eventually released the rest of the ordinary Goguryeo soldiers. However, the Tang army could not breach into the city of Ansi, which was defended by the forces of Yang Manchun. Tang troops attacked the fortress as many as six or seven times per day, but the defenders repulsed them each time. As days and weeks passed, Emperor Taizong considered abandoning the siege of Ansi to advance deeper into Goguryeo, but Ansi was deemed to pose too great of a threat to abandon during the expedition. Eventually, Tang staked everything on the construction of a huge mound, but it was captured and successfully held by the defenders despite three days of frantic assaults by Tang troops. Furthermore, exacerbated by worsened conditions for the Tang army due to cold weather (winter was approaching) and diminishing provisions, Emperor Taizong was compelled to order a withdrawal from Goguryeo on October 13, but left behind an extravagant gift for the commander of Ansi Fortress. Tang Taizong's retreat was difficult and many of his soldiers died.
  Taizong himself tended to the injuries of the Tujue Generals Qibi Heli and Ashina Simo, who were both wounded during the campaign against Goguryeo.
caption: First conflict of the Goguryeo-Tang War
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