Submarines of the Imperial Japanese Navy
Imperial Japanese Navy submarines originated with the purchase of five Holland type submarines from the United States in 1904. Japanese submarine forces progressively built up strength and expertise, becoming by the beginning of World War II one of the world's most varied and powerful submarine fleets.
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.