The Korean emperor Kojong was forced to abdicate in 1907 and his son became the powerless, puppet emperor of Korea. Kim Kojong's son, the last prince of the Chosun Dynasty, was installed as King Sunjong (1874-1926). He was a pro-Japanese and approved the Annexation Agreement signed on August 22 and promulgated on August 29, 1910 that meant Korea was officially annexed to Japan. Japan annexed Korea to enhance the prosperity of the Japanese people and to serve as a springboard for a later Japanese invasion of China. The signing of the annexation treaty by the Prime Minister happened without the approval of the Korean people. A week after the treaty was signed, King Sunjong was forced to issue a proclamation yielding both his throne and his country.
The Chosun Dynasty that had been founded by Yi Sung Gye 519 years before, now became a part of Japan. Many of the pro-Japanese Koreans were rewarded with Japanese royal titles, were given large tracts of land, and they became rich and powerful under Japanese rule. Segregated Korean and Japanese schools were established, with the Koreans receiving an inferior education. Many Koreans who grew up in that era still cannot read the Korean language.
After 1905, Japan's assertion of power was accomplished substantially at Korea's (and after 1931, at China's) expense. Nonetheless, Korean resistance to Japanese colonialism grew strong. The Japanese estimated that there were almost 70.000 Korean guerrillas in 1908 engaging Japanese forces in nearly 1,500 separate confrontations. Between 1905 and 1910, Korean people's resistance to Japanese occupation led to killing of at least 18,000 protesting Koreans, 12.000 of them from 1908 to 1910 alone.