Goguryeo against Sui and Tang

In 612 Emperor Yang of Sui led 1,133,800 soldiers against Goguryeo; of the 305,000 picked men sent toward Pyongyang, 2,700 made it back.

For about seventy years Goguryeo stood between the Korean peninsula and the reunited empire in China. First the Sui dynasty and then the Tang sent huge armies across the Liao River, and Goguryeo beat them back again and again. In the end it fell in 668, not to China alone but to an alliance of Tang and Silla, after Baekje had already been destroyed in 660. This unit follows those wars from the first clash in 598 to the fall of Pyongyang.

Goguryeo strikes first, 598

The Sui reunified China at the end of the sixth century and began pushing into the north-east. Rather than wait, King Yeongyang struck first: in the second month of 598 he attacked the Liaoxi region with about ten thousand troops, including Malgal warriors. Emperor Wen of Sui answered with an army and navy of 300,000. The land army met floods and ran short of food, and the campaign failed.

The Salsu victory, 612

Emperor Yang, the next Sui ruler, led the largest campaign himself. In the first month of 612 he set out with 1,133,800 soldiers and twice as many porters. He insisted on deciding every advance and halt himself, so his commanders could not react quickly, and Goguryeo used the delay to strengthen its defences. The Sui army could not even take Yodong fortress. A naval force reached Pyongyang ahead of the land army, was lured into a trap and lost most of its men.

Sui attacked twice more, in 613 and 614, and failed both times. The wars drained the empire, and in 618 the Sui dynasty fell.

Tang Taizong and the siege of Ansi

The Tang dynasty, founded in 618, kept expanding. Goguryeo built a long wall, the Cheolli Jangseong, from Bisa-seong in the south-west to Buyeo-seong in the north-east, completed in 647. In 642 Yeon Gaesomun, leader of the hard-line military faction, killed the ministers who opposed him and King Yeongnyu, put the king’s nephew Bojang on the throne and took power himself. In 645 Emperor Taizong of Tang invaded: Li Ji led 100,000 men by land and Zhang Liang 70,000 by sea, and Taizong commanded his own six armies. Several fortresses fell, including Yodong and Baegam. Ansi held out for dozens of days. The Tang built an earthen ramp beside it, but the ramp collapsed, and Goguryeo soldiers seized it. With the Xueyantuo nomads threatening Tang from the north, Taizong had to withdraw.

Baekje falls, 660

After Taizong died in 649, Tang changed its plan at Silla’s suggestion: destroy Baekje first, then Goguryeo. In 660 a Tang fleet came by sea while the Silla army under Kim Yu-sin marched west. King Uija of Baekje gave the general Gyebaek 5,000 men to stop the Silla army at Hwangsanbeol, in today’s Nonsan. Gyebaek set up three camps on high ground and held off much larger Silla forces for a time before he was killed. In the seventh month of 660 Baekje fell. Resistance went on for several years; in 663 a Japanese fleet sent to help the Baekje restoration forces was defeated at the Baekgang river mouth.

Goguryeo falls, 668

Tang attacked Goguryeo again in 661 and 662 and was defeated; one Tang army was wiped out near Pyongyang, its commander Pang Xiaotai killed together with his thirteen sons. What finally broke Goguryeo was a split at the top. Yeon Gaesomun died around 666, and his sons fought over power; the eldest, Yeon Namsaeng, went over to Tang, and Yeon Gaesomun’s younger brother handed territory to Silla. In the ninth month of 667 Tang took Sinseong, and in the ninth month of 668 Pyongyang fell. King Bojang and Yeon Gaesomun’s younger sons, Namgeon and Namsan, were taken to the Tang capital as prisoners.