Sui Yangdi -- a very special emperor

[Ian_Lee]

Bhchao:

Pyongyang was the location of the military commandery of Han's 樂浪 county. And in Chinese, Pyongyang carries the meaning of "Pacify the Territory".

[bhchao]

Ian, actually Korean national identity already started to develop during Tang's occupation of Koguryo. Why? Tang forcibly relocated Koguryo officials, 200,000 prisoners, and a sizeable number of the population to China.

Tang China feared that given Koguryo's unyielding spirit and formidable fighting abilities, the population might someday rebel against the Tang occupation forces and restore the Koguryo monarchy to the throne. To prevent this from happening, Tang decided on a policy of relocation where the displaced were sent to peripheral regions in China.

Many Goguryeons escaped and voluntarily defected to Silla (even though Silla was primarily responsible for destroying their kingdom), and joined the Silla-led effort to oust Tang Chinese forces from the peninsula, rather than be involuntarily moved to China.

Koryo later tried to recover the former Koguryo land in Manchuria, but the general Yi Song-gye revolted against his king and founded the Yi Dynasty. Otherwise, much of Manchuria today would be classified as Korean territory.

I think this is why PRC is fearful that in the event of a reunification between North and South Korea, the large number of Korean emigres today in Manchuria would want the territory to be annexed as part of a unified Korea.

[Ian_Lee]

Bhchao:

Silla didn't harbor any resentment towards the Tang court. In fact, after Tang garrisons pulled out of the peninsula, Silla underwent an overwhelming sinicization campaign with tens of thousands of merchants, court officials, students, monks and even military generals working in Tang China.

Though some Koguryo retainers escaped to Silla, I seriously doubt if they would ever be held in important positions by Silla court since Koguryo and Silla had been diehard adversaries for centuries.

Later the Koguryo retainers did establish a kingdom of Parhae in the current day Liaoning/Jilin provinces. But they were destroyed by the Khitans and their people escaped to Koryo:

http://www.chinese-forums.com/index.php?/topic/880-pohaiparhae

Why did Yi Song-gye revolt against Koryo?

Most likely it was the idea of Ming Court which was extremely dissatisfied with the cozy relationship between the royal family of Koryo and the ousted Mongol Yuan court.

[bhchao]

Silla didn't harbor any resentment towards the Tang court. In fact, after Tang garrisons pulled out of the peninsula, Silla underwent an overwhelming sinicization campaign with tens of thousands of merchants, court officials, students, monks and even military generals working in Tang China.

That is true. Even though Tang tried to subjugate Silla after the fall of Koguryo, Silla was quite receptive to Tang cultural influences after Tang pulled out.

Yi Song-gye was also a strong supporter of friendly relations with China. That is another reason why he didn't like the Koryo king's order of launching an excursion into northeastern China to attack Ming forces in Liaoning.

Koryo, like China during Yuan dynasty, was under Mongol occupation. It only recovered its independence after Ming overthrew Yuan and pushed the Mongols back into the steppes. Since Koryo had just benefited from Ming's overthrow of Yuan, Yi Song-gye deeply resented the pro-Mongol faction within the Koryo court.

Both China and Korea shared a mutual security interest throughout their histories. Ming China needed friendly relations with the Yi Dynasty to protect China's northeastern flank against the Mongols in the north. Yi also needed Ming stability as a buffer against future Mongol threats. That's why Yi Song-gye turned back right when he was about to cross the Yalu into China.

It was always in China's best interest to see a Korea devoid of hostile foreign occupation bordering its northeastern flank. This explains why Ming sent troops to aid the Koreans during the Japanese invasions of Korea in 1592 and 1597. And the reason why Hideyoshi invaded Korea is because the Koreans refused to let him cross the peninsula to invade China.

This security interest also explains why Mao intervened in Korea when UN forces neared the Yalu.