Korea in Chinese history

In 108BC the Han emperor Wudi conquered the northern part of the Korean peninsula. The Han empire proceeded to administer the area around modern Pyongyang for nearly 400 years.
Memories of such early conquests inspired later Chinese rulers. The Sui dynasty, after reunifying China in the sixth century AD, soon turned their sights on their neighbours. At the time, the Goguryeo kingdom ruled central and northern Korea and held territory extending into parts of Manchuria and Siberia. They considered themselves to be on a par with the Sui emperors. The Sui disagreed. Yet their campaign to chastise the recalcitrant Goguryeo proved disastrous. Despite having mobilised more than 1m soldiers, the Sui armies failed to make substantial gains on the battlefield. The expense of money and manpower crippled their dynasty. Within a few decades the Sui had given way to an even mightier Chinese empire: the Tang.
Like their Sui predecessors, the new rulers were obsessed with bringing Goguryeo to heel. Then, as now, Korea was divided among warring states. The Tang allied with one of Goguryeo’s Korean enemies in a protracted struggle for supremacy on the peninsula. In 668, the Tang armies with their Korean allies finally captured the Goguryeo capital of Pyongyang. Unfortunately for the Tang, they misjudged their own allies in Korea, who turned on the Chinese interlopers soon after and forced them back over the Yalu river, across the border from modern Korea.
In the 13th century, the Mongol Yuan dynasty used Korea as a jumping-off point for what was supposed to be an invasion of the Japanese islands. A stout Japanese defence and a fortuitous wind storm prevented the Mongols from landing and provided fodder for the myth of the “Divine Wind”—kamikaze—that protected Japan from invaders.
A few centuries later, into the rule of the Ming dynasty, Japan enjoyed the opportunity to turn the tables. Toyotomi Hideyoshi launched a series of invasions of the Asian mainland, again using Korea as his point of attack. While Koreans suffered the worst of Hideyoshi’s aggression, his stated goal was nothing short of the complete conquest of China. At the time Korea was a tributary state of the Ming, sending missions bearing gifts in exchange for nominal protection, and so Japan’s challenge could not go unanswered. While the combined armies of the Ming and the Koreans managed to beat back the Japanese invasion, the war devastated the peninsula.
Nor did Korea fare much better against the Ming’s hated rival, the Qing empire of Manchuria. Straddling the zone between the Ming Empire and Korea, the Manchus began by pressing the Koreans to renounce their loyalty to the Ming court. In 1636, eight years before they conquered China itself, the Manchus had forced the Korean government to submit to Manchu authority. When the Manchus moved south and changed the name plates at the Forbidden City, one of the first visitors was a Korean delegation which came bearing tribute to the new lords of China.
In the 19th century, Korea’s continuing status as a tributary would lead China once again into war with Japan over the fate of the peninsula. Not long after the Meiji restoration of 1868, the Japanese started aggressively testing China’s willingness to defend her tributary satellites. In a mixture of imperial expansion and employment programme (for legions of suddenly unemployed samurai), the Japanese army sought to wrest the Ryukyu islands and Korea from China, as concessions. Alarmed, the Chinese sent an official to Seoul to act as a “resident counsellor” for the Korean king. His charge, somewhat ironically, was to preserve Korean independence in the face of Japanese ambitions.
Finally, in 1894 a rebellion at the court in Seoul provided Japan with a critical opportunity. Japanese troops seized the palace and installed a regent loyal to their own interests. The war that resulted was an outright disaster for China. The humiliating peace treaty that China signed with Japan gave “full and complete independence and autonomy” to Korea. In reality, Korea had swapped one suzerain for another. Japan would complete the process in 1912 by annexing Korea. This gave imperial Japan a foothold on the mainland for its eventual conquest of Manchuria and China, in what was to become the second world war.

tracking back:http://www.ecocn.org/thread-185686-1-1.html