The Eulsa Treaty or Japan-Korea Protectorate Treaty was made between the Empire of Japan and the Korean Empire on 17 November 1905, influenced by the result of the Russo-Japanese War. The treaty in effect made Korea a protectorate of Japan. This treaty deprived Korea of its diplomatic sovereignty. Later in 1910, full annexation of Korea by Japan followed.
Delegates of both Empires met in Seoul to resolve differences in matters pertaining to Korea’s future foreign policy; however, with the Korean Imperial palace under occupation by Japanese troops, and the Imperial Japanese Army stationed at strategic locations throughout Korea, the Korean side was at a distinct disadvantage in the discussions. On 17 November 1905, the Korean cabinet signed an agreement that had been prepared by Ito Hirobumi. Per the Agreement, Japan assumed complete responsibility for Korea’s foreign affairs, and all trade through Korean ports was to be placed under Japanese supervision.
The treaty was enacted after it received the signature of five Korean ministers; (who have been reviled by later Korean historians as the Five Eulsa Traitors):
Some officials, including most notably the Emperor Gojong of Korea, did not sign the treaty, which had led Korean historians to dispute the de jure legality of the treaty. The following, including the Emperor, are:
Nevertheless, it took effect immediately.
Gojong sent personal letters to major powers to appeal for their support against the illegal signing. As of February 21, 2008, 17 of which bearing his imperial seal have been confirmed sent by Gojong, including 7 of which are:
Afterwards, in 1907, Korean Emperor Gojong sent three secret emissaries to the second international Hague Peace Convention to protest the unfairness of the Eulsa Treaty. But the great powers of the world refused to allow Korea to take part in this conference.
Not only the Emperor but the other koreans protested against the Treaty. Jo Byeong-se and Mihn Yong-hwan, who were high officials and led resistance against Eulsa treaty, suicided as resistance. Local yangbans and commoners joined righteous armies. They were called Eulsa Euibyeong(을사의병;乙巳義兵) meaning "Righteous army against Eulsa Treaty"
This protest, the lack of the Imperial assent, and the intimidation by Japanese troops during the negotiations have been used by later historians and lawyers to question the legal validity of the treaty, as being signed under duress, though the treaty remained uncontested internationally until Japan's defeat in World War II.
The Eulsa Treaty and the subsequent unequal treaties between Korea and Japan were mutually declared "already null and void" explicitly by the Treaty on Basic Relations between Japan and the Republic of Korea of 1965.
In Japanese, the treaty is known under several names including , and .