旅順港閉塞作戦
On the night of 8 February 1904, the Japanese fleet under Admiral Tōgō Heihachirō opened the war with a surprise torpedo boat destroyer attack on the Russian ships at Port Arthur. The attack heavily damaged the and , the heaviest battleships in Russia's Far Eastern theatre, and the 6,600 ton cruiser . These attacks developed into the Battle of Port Arthur the next morning. A series of indecisive naval engagements followed, in which Admiral Tōgō was unable to attack the Russian fleet successfully as it was protected by the shore batteries of the harbour, and the Russians were reluctant to leave the harbour for the open seas, especially after the death of Admiral Stepan Osipovich Makarov on 13 April 1904. Although the actual Battle of Port Arthur was indecisive, the initial attacks had a devastating psychological effect on Russia, which had been confident about the prospect of war. The Japanese had seized the initiative while the Russians waited in port.