[2] According to the political system of the day, only the Chinese emperor was allowed to use those characters, as they signified the imperial authority of China.

On the morning of September 20, 1875, the Un'yō under the command of Inoue Yoshika was dispatched to survey Korean coastal waters.

While surveying the Western coast of Korea, the Japanese put ashore a party on Ganghwa Island to request water and provisions.

[1] News of the incident did not reach Tokyo until September 28, but the following day the Dajōkan decided to dispatch gun boats to Pusan to protect Japanese residents there.

After the incident, the Imperial Japanese Navy blockaded the immediate area and requested an official apology from the Joseon government, which was concluded with the dispatch of the Kuroda mission and the signing of the Treaty of Ganghwa on February 27, 1876, which opened the Korean Peninsula to Japanese and foreign trade.