One of the primary reasons Mr An Jung-geun was motivated to kill Ito Hirobumi was that he held the mistaken belief in the notion that Ito Hirobumi was the primary source of the slowly aligned conditions prompting an annexation of Korea into the Japanese Empire, this is proven to be a more nuanced intention in hindsight as now it is more well known that Hirobumi was also nominally opposed to an immediate annexation of Korea into the Japanese Empire.

When he was prosecuted for his assassination of Ito Hirobumi, An Jung-geun presented a myriad of 15 reasons why he went forward with killing Ito Hirobumi with reasons such as:

• Ito Hirobumi in his mind was responsible for the assassination of Empress Myeongseong. A figure opposed in the past to growing Japanese influence over Korea who was struck down by pro Japanese Korean elements who hired Japanese Ronin for this purpose. Ito was Prime Minister and a key Japanese political figure domestically at this time so the possible linkage between the Japanese government and the assassination attempt was there. Though it was more so encouraged by Miura Goro, Japanese resident minister to the Korean Empire.

• Breaking the peace of Asia, Ito Hirobumi was a key figure in leading to Japan's initial projections abroad with the incorporation of territory like the Ryukyu Islands (Okinawa is the most prominent component of these islands) and the makings of Japan's empire abroad through conflicts with Qing China in the Sino-Japanese War (1894 - 1895) that was a resounding Japanese success. This drove the Qing from Korea but also resulted in the slow march to absolute Japanese dominion over Korea.

• Deception of Emperor Meiji about Korean-Japanese relations; this reason brought forward by An Jung-geun was rooted in the belief at the time that the Imperial House of Japan was supportive of pan Asian diplomacy and did not hold expansionist views, therefore in his mind the Imperial House of Japan could not reasonably be supporting the envelopment and entrapment of Korea by Japanese interests intentionally and that some deception or subterfuge must be afoot. Ahn Jung Geun imagined that due to Ito Hirobumi's tremendous influence in Japanese politics as a privy Councillor, former Prime Minister and Resident General of Korea he was likely a voice deceiving the Emperor into inadvertently supporting the slow integration of Korea. As history has proven of course the Japanese Imperial Household was supportive of the Japanese government's efforts to incorporate Korea and Ito Hirobumi was in fact a key voice supporting the retention of nominal Korean sovereignty to begin with resulted in a miscalculation from Ahn Jung-geun and resulted in the Japanese annexation of Korea outright within a year.

• Another myriad of reasons were related to the degradation and gradual suppression of Korean culture and language that did occur under Imperial Japan's influence such as the banning of studying abroad for Koreans, the confiscation and destruction of textbooks in Korean. As well as the usurping of Korean institutions by force with the Japanese Army and the abolition of the Korean Empire's Armed Forces. These reasons were very much concrete facts as even during the time as reducing the Joseon Empire to a protectorate the Japanese had a clear cut intention of treating Korea as an inferior civilization that Japan could "uplift" through education in the Japanese manner.

After exclaiming those statements and several other outlandish ones such as Ito being supposedly responsible for the assassination of Emperor Meiji's father Emperor Komei he exclaimed to the court: "I, as a lieutenant general of the Korean resistance army, killed the criminal Itō Hirobumi because he disturbed the peace of the Orient and estranged the relationship between Korea and Japan. I hoped that if Korea and Japan be friendlier and are ruled peacefully, they would be a model all throughout the five continents. I did not kill Itō misunderstanding his intentions."

Ahn Jung-geun's reasons for assassinating Ito Hirobumi ranged from the genuine grievances of a Korean patriot deeply concerned with the eroding of his countries culture and sovereignty in the face of Japanese domination to the conspiratorial belief that Japan's imperialism was misguided pan Asian beliefs from the Imperial House that was malformed by politicians like Ito Hirobumi to turn what was supposed to be peaceful mutual prosperity between Korea and Japan into a subject-master relationship. It is known now that Ahn Jung-geun and many Koreans respected the Japanese Emperor as a pan Asian figure and redirected blame for the crawl of imperialism over Korea by Japan on figures of political power like Ito Hirobumi in the belief that if they were stopped the annexation would be stopped.

Ahn Jung-geun is celebrated as a patriotic figure as he assassinated a man who although now proven hesitant about the policies being implemented in Korea by Japan inevitably still enacted them as Resident-General and who represented the modern Imperial Japan that continued to grow throughout the first half of the 20th century to the suffering and detriment of Koreans. This was one of the final actions done before the abolition of the Joseon Dynasty and their outright incorporation into the Japanese Empire so it also represents a beginning for patriotic resistance to the Japanese.

Sources:

Minichiello, Sharon (1998). Japan's Competing Modernities: Issues in Culture and Democracy, 1900-1930. Honolulu: University of Hawaii Press. pp. Pg 60. ISBN 0824820800. Retrieved 21 November 2018.

Kōmei, who was strongly opposed to radical political changes, died at the age of 35. The official cause of death was smallpox. But there has been a theory widely believed at the time that the emperor was actually poisoned by the anti-Bakufu clique. See for example Chung (1910/2004, p.61), Jansen (1961, p.282), Nam (1999, p.111), and Ravina (2004, p.135).

"What Defines a Hero?". Japan Society. Archived from the original on 2007-10-04.

http://www.ndl.go.jp/portrait/e/datas/12.html (Ito, Hirobumi | Portraits of Modern Japanese Historical Figures)