In the ensuing period, the pressure did not stop. In 1875, Japan dispatched the battleship Unyo Maru to attack Ganghwado and Yeongjongdo Islands, demanding that Joseon open its doors to foreign trade missions. Ultimately, Joseon was forced to sign the highly unequal, one-sided Korean-Japanese Treaty, or Ganghwa Treaty (1876) with Japan in 1876 under military threat.

Subsequently, imperialist powers, including Japan, vied with each other to pillage Joseon’s resources. In 1897, Joseon changed its name to the Korean Empire (Daehan Jeguk) and pushed ahead with reforms and an open-door policy, but it was too late. Japan soon won major victories in its wars against the Qing dynasty and Russia, emerged as a strong power in Northeast Asia, and took steps to annex Joseon. Many Korean patriots, including Ahn Jung-geun, resisted such a plan, but to no avail. In August 1910, the Korean Empire was formally annexed by the Empire of Japan.