The Battle of Port Arthur of 8–9 February 1904 marked the commencement of the Russo-Japanese War. It began with a surprise night attack by a squadron of Japanese destroyers on the neutral Russian fleet anchored at Port Arthur, Manchuria, and continued with an engagement the following morning; further skirmishing off Port Arthur would continue until May 1904. The attack ended inconclusively.

The Battle of Chemulpo Bay was a naval battle in the Russo-Japanese War (1904–1905), which took place on 9 February 1904, off the coast of present-day Incheon, Korea.