<P> As the war progressed, the Allies found weaknesses in Japanese naval aviation . Though most Japanese aircraft were characterized by great operating range and agility, they had very little in the way of defensive armament and armor . As a result, the more numerous, heavily armed and armored American aircraft were able to develop techniques that nullified the advantages of the Japanese aircraft . The early carrier versus carrier naval battles in 1942 such as Coral Sea and Santa Cruz Island were tactical victories for the IJN but they suffered disproportionately high aircrew losses compared to the US Navy . The IJN did not have an efficient process for rapid training of aviators, as two years of training were usually considered necessary for a carrier flyer . Therefore, they were not able to effectively replace seasoned pilots lost through combat attrition following their initial successes in the Pacific campaign . The inexperience of IJN pilots who were trained in the later part of the war was especially evident during the Battle of the Philippine Sea, when their aircraft were shot down in droves by the American naval pilots in what the Americans later called the "Great Marianas Turkey Shoot". Following the Battle of Leyte Gulf, the Japanese Navy increasingly opted towards deploying aircraft in the kamikaze role . </P> <P> Although there were delays in engine development, several new competitive aircraft designs were developed during the war, but industrial weaknesses, lack of raw materials and disorganization due to Allied bombing raids hampered their mass - production . Towards the end of the conflict, several competitive plane designs were developed, such as the 1943 Shiden, but such planes were produced too late and in insufficient numbers (415 units for the Shiden) to affect the outcome of the war . Radical new plane designs were also developed, such as the canard design Shinden, and especially jet - powered aircraft such as the Nakajima Kikka and the rocket - propelled Mitsubishi J8M . These jet designs were partially based on technology received from Nazi Germany, usually in the form of a few drawings only, Kikka being based on the Messerschmitt Me 262 and the J8M on the Messerschmitt Me 163), so Japanese manufacturers had to play a key role in the final engineering . These developments also happened too late in the conflict to have any influence on the outcome . The Kikka only flew twice before the end of the war . </P> <P> Japan had by far the most varied fleet of submarines of World War II, including manned torpedoes (Kaiten), midget submarines (Ko - hyoteki, Kairyu), medium - range submarines, purpose - built supply submarines (many for use by the Army), long - range fleet submarines (many of which carried an aircraft), submarines with the highest submerged speeds of the conflict (Senkou I - 201), and submarines that could carry multiple bombers (World War II's largest submarine, the Sentoku I - 400). These submarines were also equipped with the most advanced torpedo of the conflict, the Type 95 torpedo, a 533 mm (21 in) version of the famous 610 mm (24 in) Type 93 . </P> <P> A plane from one such long - range fleet submarine, I - 25, conducted the only aerial bombing attack on the continental United States when Warrant Flying Officer Nobuo Fujita attempted to start massive forest fires in the Pacific Northwest outside the town of Brookings, Oregon on September 9, 1942 . Other submarines undertook trans - oceanic missions to German - occupied Europe, such as I - 30, I - 8, I - 34, I - 29 and I - 52, in one case flying a Japanese seaplane over France in a propaganda coup . In May 1942, Type A midget submarines were used in the attack on Sydney Harbour and the Battle of Madagascar . </P>

How many ships did the japanese navy have in ww2