Military history of Goguryeo

The Military history of Goguryeo involved wars with other Korean kingdoms; Baekje and Silla, several Chinese dynasties, and Yamato Japan. Goguryeo finally fell to a Silla-Tang alliance in 668 from exhaustion and internal strife.

Goguryeo–Baekje War


Goguryeo and Baekje, two of the Three Kingdoms of Korea, considered themselves as the successors of Buyeo kingdom. King Onjo, the founder of Baekje, is said to have been a son of King Dongmyeongseong, founder of Goguryeo. However, the relationship between two kingdoms continued as an uneasy state.

King Geunchogo (346–375) further expanded Baekje's territory to the north through war against Goguryeo. In 369, Baekje was invaded by Goguryeo, but counterattacked in the Battle of Chiyang. In 371, the Baekje army of 30,000, led by Crown Prince Geungusu, took the fortress of Pyongyang and killed Gogugwon of Goguryeo. Goguryeo's territorial expansion also had been put on hold.

In 392, with Gwanggaeto the Great in personal command, Goguryeo attacked Baekje with 50,000 cavalry, taking 10 walled cities along the two countries' mutual border. This offensive infuriated Asin of Baekje and that king subsequently planned a counter-offensive against Gwanggaeto, a plan he was forced to abandon when his invasion force was defeated by Goguryeo 393. King Asin again attacked Goguryeo in 394, and was again defeated. After several heavy defeats, Baekje began to politically crumble and the leadership of Asin came under doubt. Asin lost to Goguryeo again in 395, and he was eventually pushed back to a front along the Han River, where Wiryeseong, then Baekje's capital city located in the southern part of modern day Seoul.

In the following year, Gwanggaeto led his huge fleet in an assault on Wiryeseong, approaching by sea and river. Asin was expecting a ground invasion and was caught with his defenses down. Gwanggaeto's forces burnt about 58 walled fortresses under Baekje control, and defeated the forces of King Asin. Asin surrendered to Gwanggaeto, even handing over his brother as a Goguryeo captive as condition for maintaining his own rule over Baekje. Gwanggaeto had finally gained superiority over its longtime rival Baekje on the Korean peninsula.

In 400, Silla requested Goguryeo assistance to defend against an alliance of Baekje-Gaya-Japanese allied forces, the Baekje kingdom to the west, and the Gaya Confederacy to the southwest. King Gwanggaeto responded with 50,000 troops, defeated both Japanese and Gaya cavalry units, and made both Silla and Gaya submit to his authority. In 401, he returned to King Silseong of Silla, to establish peaceful relationship between two kingdom while he continued the conquest of the north, but Goguryeo forces remained and continued to influence Silla.

In 433, Baekje and Silla formed an alliance (Hangul: 나제동맹, Hanja: 羅濟同盟) in response to the Goguryeo threat.

In 472, King Gaero of Baekje sent a letter to the emperor of Northern Wei. He stated that he was having trouble interacting with Wei because of frequent Goguryeo intervention, thus calling for military action against Goguryeo.

King Jangsu, eldest son of Gwanggaeto the Great, sought for the chance to invade the southern kingdoms of Korea, Baekje and Silla. As a result, King Jangsu secretly planned to attack Baekje. To disarm Baekje, he sent a Buddhist monk named Dorim. Dorim went to King Gaero's court, with the secret objective of corrupting the country before the invasion of Goguryeo. King Gaero began to favor Dorim, and played baduk with him every day, and the was able to talk Gaero into spending large sums of money on construction projects, which weakened the national treasury.

In 475, King Jangsu launched a full-scale invasion from both land and sea against the now politically unstable kingdom of Baekje. King Gaero was not at all prepared for the assault formulated by Goguryeo and King Jangsu. With momentum now in his favor, Jangsu then proceeded toward the capital and easily captured the city of Wiryesong, and slew King Gaero. Soon after, King Jangsu burnt the capital to the ground. Baekje moved its capital to Ungjin (present-day Gongju) to keep the kingdom alive. The war gave Goguryeo more or less total control of the Han River valley, the region essential to commercial and military power in the Korean Peninsula.

In 551, Baekje and Silla attacked the Goguryeo. The result of this allied attack on Goguryeo was the conquest of the Han river. In 553, Silla invaded Han River region and took the entire Han River region.

In mid-7th century, Gogureyo and Baekje formed an alliance (Hangul: 여제동맹, Hanja: 麗濟同盟) to territorial restoration, which was violated by Silla. The alliance had lasted until fall of Baekje in 660.

Goguryeo–Silla War
Goguryeo–Silla relationship also almost keep the hostile relations like the Goguryeo–Baekje relationship.

In 245, King Dongcheon of Goguryeo ordered attacking to the Silla territory, but two kingdoms entered into friendly relations in 248.

In 400, Silla requested Goguryeo assistance to defend against an alliance of Baekje-Gaya-Japanese allied forces. Goguryeo's forces expelled invaders from Silla territory, and had Silla under their influence. King Nulji of Silla worked to freedom of Silla from Goguryeo domination. He set up diplomatic relations with Goguryeo on an equal footing in 424, and established a military alliance with Baekje (Hangul: 나제동맹, Hanja: 羅濟同盟) in 433 to help counter the Goguryeo threat.

In 551, Silla and Baekje forces launched to northern campaign against Goguryeo. The result of this allied attack on Goguryeo was the conquest of the Han river. The kingdoms of Baekje and Silla kingdom both had agreed on splitting the conquered territory equally amongst themselves. However, King Jinheung of Silla betrayed their alliance Baekje in order to claim territories of Han River area in 553. After occupying the this region, Silla took greater control of the supremacy of Three Kingdoms.

Their hegemony didn't last very long. Goguryeo and Baekje applied political, militarily and economical pressure. Silla court wanted to be free from pressure of two kingdoms, and dispatch Kim Chun-chu to Chinese Tang Dynasty to request a military aid in 643. The two states made an offensive and defensive alliance. In 660, Goguryeo's ally, Baekje, fell to the Silla-Tang alliance; the victorious allies continued their assault on Goguryeo for the next eight years. Meanwhile, in 666 (though dates vary from 664-666), Yeon Gaesomun died and civil war ensued among his three sons.

In November 668, King Bojang of Goguryeo surrendered to Silla-Tang alliance. Goguryeo finally fell in 668.

Goguryeo–Han War
Goguryeo became a significant independent kingdom in the first century, and expanded its power in the region. By the time of Taejo of Goguryeo in 53, the five tribes became five centrally ruled districts of the kingdom, and foreign relations and the military were controlled by the king. Taejo successfully expanded Goguryeo by attacking Han China's commanderies of Lelang, Xuantu, and Liaodong, becoming fully independent from the Han commanderies.

Continuing its expansion to the northwest, Goguryeo began large-scale, organized attacks against the Chinese, as well as conquering neighboring statelets such as Okjeo and Dongye.

Goguryeo–Wei War
In 244, Guanqiu Jian, a general of Han's successor state Cao Wei, defeated King Dongcheon and briefly occupied Goguryeo's capital, but did not hold the territory permanently.

Goguryeo–Sui War
The Sui Dynasty was founded in 581. It grew in power and emerged as a powerful dynasty in China, defeating and conquering large forces of "Barbarians" to the North, Northwest, West, and South of China. Many neighbors of China were now forced to pay yearly tribute to the Sui Dynasty. Finally, only Goguryeo was left to be brought to its knees, but Goguryeo did not give into demands for tributes and the following threats.

Additionally, Goguryeo's expansion conflicted with the Sui Dynasty and increased tensions. In 598 the Sui, provoked by Goguryeo military offensives (pre-emptive strike) in the Liaodong region, attacked Goguryeo in the first of the Goguryeo–Sui Wars. In this campaign, as with those that followed in 612, 613, and 614, Sui met with costly defeat.

One of Sui's most disastrous campaigns was the campaign of 612, in which Sui mobilised at least 1,138,000 combat troops. General Eulji Mundeok, led the Goguryeo troops to victory by luring the Sui troops into a trap outside of Pyongyang. At the Battle of Salsu River, Goguryeo soldiers released water from a dam, which overwhelmed the Chinese army and drowned nearly every Chinese soldier. Chinese histories record that of the over 305,000 Sui troops, a mere 2,700 returned.

The wars depleted the national treasury of the Sui Dynasty and after revolts and political strife, the Sui Dynasty disintegrated in 618. However the wars exhausted Goguryeo's strength and its power declined.

Goguryeo–Tang War
Under Tang Taizong, the Tang Dynasty forged an alliance with Goguryeo's rival Silla after defeating Goguryeo's western ally, the Göktürks. Later in Tang Taizong reign, he also began campaigns against the Goguryeo, much to the opposition of many advisors.

In 645, Taizong commanded an army of 100,000 Tang soldiers. Taizong's noted army enabled him to conquer a number of border city fortresses of Goguryeo. The Tang army in several cases defeated the Korean forces on open battlefields. Outside the Ansi Fort, Go Yeonsu and Go Hyezin had mobilized 150,000 troops, though it proved to be fruitless. After tactics by Taizong with Li Shiji commanding 15,000 men and Zhangsun Wuji with 11,000 coming from behind, the Korean generals were confused and defeated, the losses were 20,000 for the Koreans and 36,000 captured.

However, forts would be the one issue that the Tang Taizong couldn't solve, most particularly Ansi fortress itself. the remaining Goguryeo troops get in inside Ansi fortress. Ansi was under siege by the Tang army. However Tang was not able to conquer Ansi fortress. After a protracted siege, Taizong ordered the construction of a large siege ramp by making a mountain of soil to tower over the high Ansi walls. As the mountain rose higher, so did the walls as it was raised higher with wooden extensions. However the siege mountain collapsed. In mid-September 645, the harsh winter worsened the conditions for the Tang army, which compelled Emperor Taizong to withdraw his forces from Goguryeo.

After Taizong's death in 649, the conquest of Goguryeo and the personal rivalry with Yeon Gaesomun became an obsession with Taizong's son Gaozong. He invaded Goguryeo numerous times but Yeon turned the Tang back every time-perhaps most notably during Yeon's celebrated annihilation of the Tang forces in 662 at the Sasu River (蛇水) where the invading general Pang Xiaotai (龐孝泰) and all 13 of his sons were killed in the battle.

As a result while Yeon Gaesomun was alive, Tang was not able to conquer the Goguryeo.

Fall of Goguryeo and Foundation of Balhae
Goguryeo's ally in the southwest, Baekje, fell to the Silla-Tang alliance in 660 the victorious allies continued their assault on Goguryeo for the next eight years. Meanwhile, in 666 (though dates vary from 664-666), Yeon Gaesomun died and civil war ensued among his three sons. One of his sons, Yeon Namsaeng fled to Tang and was a big part in the next invasion of Goguryeo by the Tang and served as the primary key to the downfall of Gogureyo, as only when he came did the Tang's emperor was willing to send troops to Goguryeo, since the defector knew the most of the weaknesses and shortcuts that Tang forces did not know of, into Goguryeo's fortified territory. diagonally opposite another son, Yeon Namgeon resist in the face of death to his brother's treachery.

Silla–Tang eventually vanquished the weary kingdom, which had been suffering from a series of famines and internal strife. Goguryeo finally fell in 668.

Silla thus unified most of the Korean peninsula in 668, but the kingdom's reliance on Chinese Tang Dynasty had its price. Silla had to forcibly resist the imposition of Chinese rule over the entire peninsula, which they did and eventually expelled the Tang. Silla'a unification of Korea was short lived for the former Goguryeo General Dae Joyeong led the remnants of Goguryeo, united with the Mohe and established Balhae, Known to Koreans as the successor of Goguryeo and retained much of its former territory.

The Balhae would become a buffer in trade and was a powerful empire that Tang could not bother. Their end would come from the Khitan in 926. This end was a decisive event in Northeast Asian history for it was the last Korean Kingdom to hold territory in Manchuria.

Goguryeo–Yan War
The expansion met temporary setbacks when in 342, Former Yan, of Xianbei ethnicity, attacked Goguryeo’s capital and captured it briefly, taking the body of King Micheon (the father of then-reigning King Gogugwon) and Queen Ju (King Gogugwon's mother) as collateral for Goguryeo's submission.

However, In 400, Later Yan, successor state of Former Yan, attacked Goguryeo. Gwanggaeto the Great responded swiftly, recovering most of the territory seized by the Xianbei and driving most of them from Goguryeo. Then in 402, he decided to launch an attack on Later Yan itself, determined to protect his Kingdom from further threat. In the same year Gwanggaeto defeated the Xianbei, seizing some of their border fortresses. In 404, he invaded Liaodong and took the entire Liaodong Peninsula. In 409, Goguryeo appears to have captured all territory east of the Liao River held by Later Yan.