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, though the war resulted in a decisive Japanese victory.
The opening stage of the Russo-Japanese War began with pre-emptive strikes by the Imperial Japanese Navy (IJN) against the Russian Pacific Fleet based at Port Arthur and at Chemulpo. Admiral Tōgō's initial plan was to swoop down upon Port Arthur with the 1st Division of the Combined Fleet, consisting of the six pre-dreadnought battleships , , , , and , led by the flagship , and the 2nd Division, consisting of the armored cruisers , , , , and . These capital ships and cruisers were accompanied by some 15 destroyers and around 20 smaller torpedo boats. In reserve were the cruisers , , , and . With this large, well-trained and well-armed force, and surprise on his side, Admiral Tōgō hoped to deliver a crushing blow to the Russian fleet soon after the severance of diplomatic relations between the Japanese and Russian governments.
On the Russian side, Admiral Starck had the pre-dreadnought battleships , , , , , , and , supported by the armored cruiser and the protected cruisers , , , , and , all based within the protection of the fortified naval base of Port Arthur. However, the defenses of Port Arthur were not as strong as they could have been, as few of the shore artillery batteries were operational, funds for improving the defenses had been diverted to nearby Dalny, and most of the officer corps was celebrating at a party being hosted by Admiral Starck on the night of 9 February 1904.
As Admiral Tōgō had received false information from local spies in and around Port Arthur that the garrisons of the forts guarding the port were on full alert, he was unwilling to risk his precious capital ships to the Russian shore artillery and therefore held back his main battle fleet.