Submarines of the Imperial Japanese Navy
Imperial Japanese Navy (IJN) submarines formed by far the most varied fleet of submarines of World War II, including manned torpedoes ("Kaiten"), midget submarines ("Kō-hyōteki", ), medium-range submarines, purpose-built supply submarines (many used by the Imperial Japanese Army, see Type 3), fleet submarines (many of which carried an aircraft), submarines with the highest submerged speeds of the conflict ("Sentaka" ), and submarines able to carry multiple bombers (World War II's largest submarine, the Sentoku ). They were also equipped with the most advanced torpedo of the conflict, the oxygen-fuelled Type 95 (which are sometimes confused with the famed Type 93 Long Lance torpedo).
List of warships sunk during the Russo-Japanese War
Although submarines, torpedoes, torpedo boats, and steel battleships had existed for many years, the Russo-Japanese war was the first conflict to see mature forms of these weapon systems deployed in large numbers. Over a hundred of the newly invented torpedo boats and nearly the same number of torpedo boat destroyers were involved. The Imperial Russian Navy would become the first navy in history to possess an "independent operational submarine fleet" on 1 January 1905. With this submarine fleet making its first combat patrol on 14 February 1905, and its first clash with enemy surface warships on 29 April 1905, all this nearly a decade before World War I even began.