In 1885 Ito Hirobumi negotiated the Convention of Tientsin with Li Hung-chang which stated that Born in Hagi, Yamaguchi, Prince Itō Hirobumi (伊藤 博文 Itō Hirobumi 1841–1909, also called Hirofumi/Hakubun) was a Japanese politician and the countrys first Prime Minister (and the 5th, 7th and 10th). ... Li Hongzhang (Chinese: 李鴻章; pinyin: Lǐ Hóngzhāng, Wade-Giles: Li Hung-chang) (February 15, 1823 - November 7, 1901) was a general who ended several major rebellions, and a leading statesman of the late Chinese Qing Empire. ...
(a) pull their expeditionary forces out of Korea simultaneously; (b) not send military instructors for the training of the Korean army; and (c) notify the other side beforehand should one decide to send troops to Korea. Korea (한국) is a formerly unified country, situated on the Korean Peninsula in northern East Asia, bordering on China to the west and Russia to the north. ...
The Chinese government informed the Japanese government of its decision to send troops to the Korean peninsula in accordance with the Convention of Tientsin, and sent General Yuan Shikai as its plenipotentiary at the head of 2,800 troops.
The Japanese countered that they consider this action to be a violation of the Convention, and sent their own expeditionary force (the Oshima Composite Brigade) of 8,000 troops to Korea.
The Japanese force subsequently seized the emperor, occupied the Royal Palace in Seoul by 8 June 1894, and replaced the existing government with the members from the pro-Japanese faction.
It was agreed by this convention that Japan and China should withdraw troops from Korea, that they should not furnish Korea with military instructors, and that if it should become necessary at any future time for either party to send soldiers to Korea, it should notify the other of its intention.
China, on her part, equally resented the conclusion of the convention, for she was thereby obliged to treat Japan on an equal footing with herself in Korea.
Japan's answer was that the sending of the troops was in accordance with the Korean-Japanese convention of 1882, and that she had the right to determine the number and disposition of her own forces.