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).
Imperial Japanese Navy
The Imperial Japanese Navy acquired its first submarines in 1905 from Electric Boat Company, barely four years after the U.S. Navy had commissioned its own first submarine, . The ships were Holland designs and were developed under the supervision of Electric Boat's representative, Arthur L. Busch. These five submarines (known as Holland Type VII's) were shipped in kit form to Japan (October 1904) and then assembled at the Yokosuka, Kanagawa Yokosuka Naval Arsenal, to become hulls "No.1" through "5", and became operational at the end of 1905.