Emperor Taizong's campaign against Goguryeo

Infobox Military Conflict
conflict=Emperor Taizong's campaign against Goguryeo
partof=Goguryeo-Tang Wars


caption=
date= 644-645
place=Liaodong Peninsula
territory=
result=Tang withdrawal
combatant1=Tang Dynasty
combatant2=Goguryeo (in alliance with Mohe)
combatant3=
commander1=Emperor Taizong of Tang Li Shiji Li Daozong Zhangsun Wuji Zhang Liang
commander2=Go Yeonsu Go Hyezin Yang Manchun
commander3=
strength1=~100,000"Zizhi Tongjian", vols. 197, 198.] "Samguk Sagi", vol. 21. [http://www.khaan.net/history/samkooksagi/sagi2122.htm] ]
strength2=~150,000
strength3=
casualties1="Samguk Sagi" states losses were heavy on both sides, although it did not give figures.
casualties2=~40,000 (Goguryeo forces)/~3,300 (Mohe forces)"Zizhi Tongjian", vol. 198. However, the "Samguk Sagi" implied that the losses were much heavier on both sides than reported by Chinese sources, although it did not give figures.]
casualties3=
notes=

Emperor Taizong of Tang (r. 626-649), the second emperor of Chinese dynasty Tang Dynasty, asserting that a campaign against Goguryeo was necessary to protect Tang's ally Silla, as well as to punish Goguryeo's "Dae Mangniji" (막리지/莫離支, regent) Yeon Gaesomun for his killing of Goguryeo's King Yeongnyu, launched a major campaign against Goguryeo in 644, commanded by himself with the assistance of the generals Li Shiji, Li Daozong, and Zhangsun Wuji. In 645, after defeating the main Goguryeo army, Emperor Taizong appeared poised to march on Goguryeo's capital Pyongyang and conquer Gogureyo, but became bogged down by the strong defenses put up by the defender of Anshi/Ansi (安市, in modern Anshan, Liaoning) -- whose name is lost to history but is traditionally believed to be Yang Manchun -- and was unable to proceed further. Thereafter, for the rest of his reign, Emperor Taizong limited his attack on Goguryeo to harassment raids, and would not again launch a major attack. After Tang and Huige destroyed Xueyantuo in 646, Emperor Taizong started to built up his army and navy in anticipation for another major campaign in 649, but Emperor Taizong died that same year, stalling the campaign. The Tang Dynasty failed to conquer Goguryeo until 668. In 668, Tang destroyed Goguryeo in alliance with Silla, during the reign of Emperor Taizong's son Emperor Gaozong.

Background

Failures of three campaigns against Goguryeo during the reign of Emperor Yang of Sui had been one of the major reasons for the downfall of Tang Dynasty's predecessor, Sui Dynasty. After Tang was founded in 618, Tang's founder Emperor Gaozu made peace with Goguryeo's King Yeongnyu, with the states making an exchange of prisoners of war in 622 and with King Yeongnyu subsequently, in 624, accepting Tang era name and the Tang-created titles of Prince of Liaodong and King of Goguryeo. (At the same time, Emperor Gaozu also created the kings of Goguryeo's two southern neighbors princely titles --Baekje's King Mu as the Prince of Daifang and Silla's King Jinpyeong as the Prince of Lelang.)

In 626, Emperor Gaozu's son Li Shimin the Prince of Qin, locked in an intense rivalry with his older brother Li Jiancheng the Crown Prince, ambushed and killed Li Jiancheng and another brother who supported Li Jiancheng, Li Yuanji the Prince of Qi, at the Incident at Xuanwu Gate. He then effectively forced Emperor Gaozu to first create him crown prince and then pass the throne to him (as Emperor Taizong). For most of Emperor Taizong's reign, the relationship between Tang and Goguryeo appeared to be largely friendly, with Emperor Taizong trying to assert more of an overlord role over the dispute between Goguryeo and its rivals Baekje and Silla. For example, soon after Emperor Taizong took the throne in 626, he sent his official Zhu Zishe (朱子奢) to rebuke the three states for attacking each other. In 631, Emperor Taizong sent emissaries to Goguryeo to rebury the Sui war dead, which King Yeongnyu permitted.

In 641, Emperor Taizong sent the official Chen Dade (陳大德) as an emissary to Goguryeo, and on the trip, Chen traveled throughout Goguryeo and met a large number of former Sui soldiers who had settled in Goguryeo, and upon return to the Tang capital Chang'an, he reported his findings to Emperor Taizong. Emperor Taizong began contemplating attacking Goguryeo, but then dismissed his own idea, stating that he did not want to trouble the people in the eastern part of his empire.

In 642, however, an event that would trigger Emperor Taizong to rethink his position occurred. King Yeongnyu had been considering to kill his general Yeon Gaesomun, believing Yeon to be violent and criminal. Yeon, after receiving such news, set a trap for the king and a number of officials under guise of a banquet and view of troops, and then killed both the officials and the king. He supported King Yeongnyu's brother Go Jang as king (as King Bojang). Yeon himself took the title of "Mangniji" (regent) and had the actual control of the government and the military. When the news reached Tang, the official Pei Xingjuang (裴行莊) suggested attacking Goguryeo, which Emperor Taizong again declined, stating that he mourned King Yeongnyu but that it would be inappropriate to attack Goguryeo in light of King Yeongnyu's death. However, in 643, he again considered military options, but initially considered only ordering the Khitan and the Mohe to harass Goguryeo. Emperor Taizong's brother-in-law, the chancellor Zhangsun Wuji opposed this and suggested instead assuring Yeon with offers of peace and then to catch him offguard. Emperor Taizong agreed, and affirmed King Bojang's ascension by creating him the Prince of Liaodong and King of Goguryeo, along with the honorific title of "Shang Zhuguo" (上柱國).

Later in 643, Silla's Queen Seondeok submitted a report claiming that her state was under heavy attack by Baekje, allied with Goguryeo. She requested aid from Tang. Emperor Taizong sent the official Xiangli Xuanjiang (相里玄獎) to Goguryeo to order both it and Baekje to stop attacking Silla. When Xiangli arrived in the Goguryeo capital Pyongyang, Yeon, who was attacking Silla at that time, returned to Pyongyang to meet with Xiangli, but refused to follow Emperor Taizong's order. When Xiangli returned to Chang'an and reported this to Emperor Taizong, Emperor Taizong resolved to attack Goguryeo, stating:

The general Li Shiji was particularly supportive of the plan to attack Goguryeo, and Emperor Taizong decided to prepare for such a campaign, notwithstanding the opposition of Chu Suiliang.

Tang advance

In fall 644, in preparation for the attack, Emperor Taizong had his official Yan Lide (閻立德) personally visit the southern Chinese prefectures of Hong (洪州, roughly modern Nanchang, Jiangxi), Rao (饒州, roughly modern Shangrao, Jiangxi), and Jiang (江州, roughly modern Jiujiang, Jiangxi) to build some 400 supply ships for the campaign. He also had the commandant at Ying Prefecture (營州, roughly modern Zhaoyang, Liaoning) command the troops from Ying and You (幽州, roughly modern Beijing) prefectures, as well as troops from Khitan, Xi, and Mohe tribes loyal to Tang to make exploratory attacks in the Liaodong region, to test what Goguryeo's responses would be. Apparently to try to ward off the attack, Yeon Gaesomun sent emissaries to offer tributes of platinum. At Chu Suiliang's suggestion, Emperor Taizong rejected the platinum and further accused the emissaries of being loyal not to their king (the deceased King Yeongnyu) but to the regicide (i.e., Yeon); he put them under arrest. In winter 644, he left Chang'an and began his slow advance to the frontier, initially taking most of his officials as well as his crown prince Li Zhi with him, leaving the chancellor Fang Xuanling and the general Li Daliang (李大亮) in charge of the capital. He headed first for the eastern capital Luoyang, where he stayed several months in further preparation.

Around the new year 645, Emperor Taizong issued orders for Zhang Liang to take some 43,000 soldiers, in 500 ships launching from Lai Prefecture (萊州, roughly modern Laizhou, Shandong), to advance across the Yellow Sea heading toward Pyongyang; and for Li Shiji to command some 60,000 soldiers to head toward Liaodong on land. Emperor Taizong, confident of success, issued an edict that stated, among other things:

In spring 645, Emperor Taizong departed Luoyang, against the advice of the retired general Yuchi Jingde, who was concerned that a rebellion similar to that Yang Xuangan started against Emperor Yang in 613 during one of Emperor Yang's Goguryeo campaigns would develop. He left another chancellor, Xiao Yu, in charge of Luoyang. Once he reached Ding Prefecture (定州, roughly modern Baoding, Hebei), he left Li Zhi there to be in charge of logistics, assisted by Gao Shilian, Liu Ji, Ma Zhou, Zhang Xingcheng, and Gao Jifu. He continued proceeding, with Zhangsun Wuji, Cen Wenben, and Yang Shidao accompanying him. (Cen would die during the campaign.)

Meanwhile, Li Shiji and his deputy, Li Daozong the Prince of Jiangxia (Emperor Taizong's cousin) had, in advance of Emperor Taizong, surprised Goguryeo forces by crossing the Liao River. By summer 645, they had captured Gaemo/Gaimou (蓋牟, in modern Fushun, Liaoning). Meanwhile, Zhang Liang had crossed the Bohai Sea and captured Bisa/Beisha (卑沙, in modern Daliang, Liaoning) and sent his forward vessels to the mouth of the Yalu River to try to intimidate Goguryeo forces, but was not heading toward Pyongyang as initially ordered by Emperor Taizong. Soon, Li Shiji and Li Daozong put the Goguryeo city of Yodong/Liaodong(遼東, in modern Liaoyang, Liaoning) -- a city that Emperor Yang had sieged multiple times but was unable to capture -- under siege, and after Emperor Taizong arrived himself, Liaodong fell, and another key city, Baegam/Baiyan (白巖, also in modern Liaoyang) surrendered. Emperor Taizong next marched on Anshi/Ansi.

Battle of Mount Zhubi

Meanwhile, Goguryeo's northern governors Go Yeonsu (高延壽, pinyin Gao Yanshou) and Go Hyezin (高惠真, pinyin Gao Huizhen) put together an army of Goguryeo troops, as well as Mohe tribes allied with Goguryeo, totalling 150,000 men, and headed toward Ansi/Anshi, intending to relieve it. When Emperor Taizong heard of the impending arrival of the Goguryeo army, he told his officials:

Meanwhile, a senior, experienced Goguryeo officer advised Go Yeonsu:

Go Yeonsu did not accept and continued to proceed to the vicinity of Anshi/Ansi. Emperor Taizong, in order to further entice him to battle, sent the ethnically Tujue general Ashina She'er (阿史那社爾) to lead 1,000 Tujue cavalry soldiers forward, and once the Tujue soldiers engaged the Goguryeo forces, they pretended to flee. The Goguryeo forces gave chase and arrived at Anshi/Ansi.

Emperor Taizong and his generals discussed the strategies, and they ascended the hills to discuss where troops could be hidden and where attacks could be made. Meanwhile, Li Daozong suggested that given that Go Yeonsu and Go Hyezin had this massive of an army, Pyongyang must be poorly defended, and he wanted to personally take 5,000 soldiers to make a surprise attack on Pyongyang, hoping to capture it. Emperor Taizong did not act on Li Daozong's proposal, but instead send a messenger to Go Yeonsu to state:

Go Yeonsu, believing that Emperor Taizong had no further intention to attack, relaxed in his preparations. Meanwhile, Emperor Taizong had Li Shiji take 15,000 soldiers and set up his camp on a hill to the west of the Goguryeo camp, and Zhangsun Wuji take 11,000 soldiers and position himself in a canyon north of the Goguryeo camp. Emperor Taizong himself took 4,000 soldiers and took up position on a hill north of the Goguryeo camp. The next day, July 20, 645, [ [http://www.sinica.edu.tw/ftms-bin/kiwi1/luso.sh?lstype=2&dyna=%AD%F0&king=%A4%D3%A9v&reign=%ADs%C6%5B&yy=19&ycanzi=&mm=6&dd=22&dcanzi= 兩千年中西曆轉換 ] ] when Go Yeonsu noticed Emperor Taizong's camp to the north, he ordered an attack. As he did, Zhangsun made a surprise attack, and Emperor Taizong also attacked. The Goguryeo forces collapsed, and 20,000 men were killed. Go Yeonsu reorganized his troops and tried to defend his position, but Tang forces had him surrounded, and Zhangsun further destroyed the bridges to prevent a retreat. Two days later, Go Yeonsu and Go Hyezin surrendered with 36,800 men. Emperor Taizong said to them:

Emperor Taizong took 3,500 senior Goguryeo officers, conferred Tang titles on them, and had them sent to Tang proper. He released the other Goguryeo soldiers and sent them back to Pyongyang, but massacred the captured Mohe soldiers -- some 3,300. In commemoration of his victory, Emperor Taizong named the location of the battle Mount Zhubi (駐驆山 -- i.e., "the mount where the imperial horse was").

After the Battle of Mount Zhubi, Yeon Gaesomun sent emissaries to Xueyantuo's Zhenzhu Khan Yi'nan, through Mohe intermediaries, to request that he attack Tang, offering to give him great tributes if he would do so. Yi'nan, in awe of Tang power, refused.

Battle of Anshi/Ansi

Emperor Taizong next prepared to put Anshi/Ansi under siege, but he had reservations about it. When he discussed the matter with Li Shiji, he stated:

(The name of the defending general of Anshi/Ansi has been lost to history, but is traditionally rendered in Korean popular accounts as Yang Manchun, even though some Korean historical sources indicated that the name was lost.)

Li Shiji disagreed, however, arguing that as Jian'an was to Anshi/Ansi's south and that the main Tang food supply was coming from Liaodong, that if he attacked Jian'an first, the defenders of Anshi/Ansi would try to cut his supply lines. Emperor Taizong agreed, and Li Shiji began to siege Anshi/Ansi.

When Emperor Taizong and Li Shiji arrived at Anshi/Ansi, it was said that the Anshi/Ansi defenders, upon seeing the banner of the Tang emperor, began to yell insults from the walls. Emperor Taizong was insulted, and Li Shiji received permission to slaughter the city's male inhabitants when it fell -- which led to the Anshi/Ansi defenders fighting even harder. Li Shiji was unable to capture the city for some time. Go Yeonsu and Go Hyezin, who had by now accepted Tang titles, suggested:

Some other officials also suggested:

Emperor Taizong was inclined to accept these proposals, but Zhangsun opposed, stating:

Emperor Taizong agreed with Zhangsun and did not head toward Wugu.

As the siege continued, on an occasion, when Emperor Taizong heard the sounds of chickens and pigs coming out of the city, he opined to Li Shiji that it must be that the Goguryeo defenders were preparing an assault and killing animals beforehand to feast on them. Li Shiji therefore prepared for a nigh assault, which came that night. Emperor Taizong himself led soldiers to repel the assault, and the Goguryeo forces withdrew within the city again.

Meanwhile, Li Daozong was building a dirt mound to the southeast of the city to use as an attack mechanism, and in response, the Anshi/Ansi defenders added to the height of the wall to the southeast. This process continued for 60 days, and eventually, the dirt mound got so high that from it, one could easily see inside the city. Li Daozong had his officer Fu Fu'ai (傅伏愛) take position on the dirt mound. Suddenly, the mound had a partial collapse and fell onto the city walls, and the walls collapsed as well. At this moment, Fu, for reasons unexplained in history, left his position, and the Goguryeo forces took the opportunity to attack and capture the dirt mound, and instead used it as part of the defensive bulwarks. Emperor Taizong, in anger, executed Fu in public and ordered a heavy assault on the dirt mound, but could not capture it within three days. Li Daozong bared his feet and begged punishment, but Emperor Taizong pardoned him.

Meanwhile, winter was approaching, and the grass was drying up. Also, the food supplies were running out. On October 13, 645, [ [http://www.sinica.edu.tw/ftms-bin/kiwi1/luso.sh?lstype=2&dyna=%AD%F0&king=%A4%D3%A9v&reign=%ADs%C6%5B&yy=19&ycanzi=&mm=9&dd=18&dcanzi= 兩千年中西曆轉換 ] ] Emperor Taizong ordered a withdrawal. He gave a demonstration ceremony next to Anshi/Ansi before withdrawing. The defender general of Anshi/Ansi climbed up the walls and bowed to him to send him off. Emperor Taizong praised him for his faithfulness to Goguryeo and sent him an award of silk. As the Tang army began to withdraw, Li Shiji and Li Daozong served as rear guards.

Tang withdrawal

Emperor Taizong suffered an injury during the Goguryeo campaign, which the historical records did not specify the nature or cause of. Later Korean sources speculated that it was an arrow wound suffered during the Battle of Anshi/Ansi, and further speculated that it was an arrow to the eye.

Emperor Taizong's army withdrew through Liaodong, and as it did, forced the people of Liaodong and Gaiping to follow the army to Tang territory. As the army was crossing the Liao River, it was trapped by the marshes near the Liao for some time, requiring Zhangsun to command 10,000 men to carry out a project to fill the marshes in to allow the main army to withdraw. As weather was getting increasingly cold at the time, a number of Tang soldiers froze to death.

In all, according to both the Chinese historical source "Zizhi Tongjian" and the Korean historical source "Samguk Sagi", some 70,000 Goguryeo people were forcibly moved to Tang territory. Some 40,000 Goguryeo soldiers were killed. The Tang forces lost anywhere from 2,000-20,000cn|date=February 2008 men and 70-80% of their horses. Emperor Taizong regretted launching the campaign, and sighed, "If Wei Zheng were still alive, he would not let me launch his campaign." He sent messengers to offer sacrifices to Wei, who had died in 643, and reerected a monument that he had previously built for Wei but which he had destroyed later in 643 after he wrongly believed that the deceased Wei had been in complicity with Hou Junji and Du Zhenglun. He also summoned Wei's wife and children to his presence and awarded them. Due to complications of his injury, he remained in Bing Prefecture (并州, roughly modern Taiyuan, Shanxi) for several months, before returning to Chang'an, and further transferred a substantial portion of his responsibilities to Li Zhi.

Aftermaths

it was said that after Emperor Taizong's withdrawal, Yeon Gaesomun became even more defiant toward Tang, and while he sent emissaries to Tang, the letters were not submissive. He was also defiant toward Tang emissaries, and also often sent scouts to venture near Tang borders. Emperor Taizong repeatedly send him edicts ordering him not to attack Silla, but he would not relent. In winter 646, Emperor Taizong issued an edict cutting off relations with Goguryeo and again considering a new campaign against Goguryeo.

In 647, Emperor Taizong, after discussions with his officials, who pointed out that the 645 campaign, while unsuccessful, had caused Goguryeo to fall into famine, accepted their proposal of sending relatively small forces to harass Goguryeo's border region to prevent Goguryeo farmers from farming and therefore to create further food supply issues for Goguryeo. He therefore had Niu Jinda (牛進達), assisted by Li Hai'an (李海岸) command a navy to attack southern Liaodong Peninsula, and Li Shiji, assisted by Sun Erlang (孫貳朗), command an army to cross the Liao River, both with intent to harass Goguryeo. Both forces consisted of soldiers who were capable of swimming. It was said that both of these forces were successful in inflicting serious losses on Goguryeo forces before withdrawing.

In 648, Emperor Taizong launched another attack over the sea, with Xue Wanche (薛萬徹) in command, assisted by Pei Xingfang (裴行方). A side attack was also launched by Gu Shen'gan (古神感). Believing that Goguryeo had been weakened by these attacks, Emperor Taizong prepared an attack, to be launched in 649, with 300,000 men, to destroy Goguryeo. Some of his officials pointed out that this would require more a year of supply of foods, and that given the massive numbers, land transport would be inadequate and that ships needed to be built. They further pointed out that throughout the disturbances that caused Sui's destruction and Tang's rise, Jiannan Circuit (劍南道, roughly modern Sichuan, Yunnan, and Chongqing) was undisturbed, and Jiannan was also uninvolved in the 645 campaign, and that Jiannan should therefore be required to build the ships. Emperor Taizong agreed and sent the official Qiang Wei (強偉) to Jiannan to commission the building of the ships, ordering that when the ships are built, they are to be taken down the Yangtze River and then on East China Sea, to report to Lai Prefecture. Additional ships were to be built by Yue (越州, roughly modern Shaoxing, Zhejiang), Wu (婺州, roughly modern Jinhua, Zhejiang), and Hong Prefectures. (Soon, however, it was discovered that the people of Jiannan Circuit were not good at building ships; instead, the people of Jiannan Circuit became only in charge of obtaining the wood for the ships, and the wood was instead shipped to Tan Prefecture (潭州, roughly modern Changsha, Hunan) to be built into ships.)

Emperor Taizong died in summer 649, and, pursuant to his will, the campaign against Goguryeo was not launched. Li Zhi succeeded him (as Emperor Gaozong), and throughout the early years of Emperor Gaozong's reign, there would be a number of campaigns against Goguryeo and its ally Baekje. Baekje fell to Tang and Silla forces in 660, but the campaigns against Goguryeo would not be successful until 669.

Kim Busik, the author of the "Samguk Sagi", who largely agreed with the Chinese accounts of the events, nevertheless commented:

See also

* Emperor Taizong's campaign against Xueyantuo
* Goguryeo-Tang Wars

Notes and references