Japanese submarine I-51
Following World War I, the Imperial Japanese Navy General Staff began to re-consider submarine warfare as an element of fleet strategy. Before the war, the Japanese Navy regarded submarines as useful only for short-range coastal point defense. However, based on the success of the Imperial German Navy in deployment of long-range cruiser-submarines for commerce raiding Japanese strategists came to realize possibilities for using the weapon for long range reconnaissance, and in a war of attrition against an enemy fleet approaching Japan. Procurement for a large, long-range Japanese submarine was authorized in fiscal 1918 under the Eight-six fleet program, under the designation S22.
"Project S22" was based on the latest Royal Navy design, the British K class submarine. Japanese ties to Great Britain via the Anglo-Japanese Alliance were still strong. "Project S22" was laid down at Kure Naval Arsenal on 6 April 1921, launched on 29 November 1921 and completed on 20 June 1924.
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.