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 in World War II
Early models were not very maneuverable under water, could not dive very deep, and lacked radar. Later in the war, units fitted with radar were in some instances sunk due to the ability of US radar sets to detect their emissions. For example, sank three such in the span of four days. After the end of the conflict, several of Japan's most innovative and advanced submarines were sent to Hawaii for inspection in "Operation Road's End" ("I-400", "I-401", "I-201" and "I-203") before being scuttled by the U.S. Navy in 1946 when the Soviets demanded access to the submarines as well.