Imperial Japanese Navy: Encyclopedia II - Imperial Japanese Navy - World War II

Imperial Japanese Navy - World War II

The Imperial Japanese Navy was administered by the Ministry of the Navy of Japan and controlled by the Chief of the Imperial Japanese Navy General Staff at Imperial General Headquarters. In order to combat the numerically superior American navy, the IJN devoted large amounts of resources to creating a force superior in quality to any navy at the time. Consequently, at the beginning of World War II, Japan probably had the most sophisticated Navy in the world.^[14] Betting on the speedy success of aggressive tactics, Japan did not invest significantly on defensive organization: she should also have been able to protect her long shipping lines against enemy submarines, which she never managed to do, particularly under-investing in anti-submarine escort ships and escort aircraft carriers.

The Japanese Navy enjoyed spectacular success during the first part of the hostilities, but American forces ultimately managed to gain the upper hand through technological upgrades to its air and naval forces, and a vastly stronger industrial output. Japan's reluctance to use their submarine fleet for commerce raiding and failure to secure their communications also added to their defeat. During the last phase of the war the Imperial Japanese Navy resorted to a series of desperate measures, including Kamikaze (suicide) actions.

Imperial Japanese Navy - Battleships

Japan continued to attribute considerable prestige to battleships and endeavoured to build the largest and most powerful ships of the period. Yamato, the largest and most heavily-armed battleship in history, was launched in 1941.

The second half of World War II saw the last battleship duels. In the Battle of Guadalcanal on November 15, 1942, the United States battleships South Dakota and Washington fought and destroyed the Japanese battleship Kirishima. In the Battle of Leyte Gulf on 25 October 1944 six battleships, led by Admiral Jesse Oldendorf of the U.S. 7th Fleet fired upon and claimed credit for sinking Admiral Shoji Nishimura's battleships Yamashiro and Fuso during the Battle of Surigao Strait; in fact, both battleships were fatally crippled by destroyer attacks before brought under fire by Oldendorf's old battleships.

Nevertheless, the Battle of Samar on 25 October 1944 during the Battle of Leyte Gulf showed that battleships still be useful, albeit inefficient weapon. Only the indecision of Admiral Takeo Kurita and the fight by American destroyers and destroyer escorts saved the American aircraft carriers of "Taffy 3" from being pounded to the bottom by the gunfire of Yamato, Kongo and Nagato and their cruiser host. Miraculously for the Americans, only USS Gambier Bay along with four destroyers were lost due to surface action. The Yamato, for all the expense that went into building her, failed to score even a single hit.

Ultimately, the advent of air power however spelled doom for the battleship. Battleships in the Pacific ended up primarily performing shore bombardment and anti-aircraft defense for the carriers. The Yamato and Musashi were sunk by aircraft attacks long before they could come within striking range of the American fleet. As a result of the changing technology, plans for even larger battleships, such as the Japanese Super Yamato class, were cancelled.

Imperial Japanese Navy - Aircraft carriers

Japan put particular emphasis on aircraft carriers. The Imperial Japanese Navy started the Pacific War with 10 aircraft carriers, the largest and most modern carrier fleet in the world at that time. Its two Shokakus were superior to any carrier in the world until the wartime appearance of the American Essex-class aircraft carrier ^[15]. However, a large number of the Japanese carriers were of small size in accordance to limitations placed upon the Navy by the London and Washington Naval Conferences. There were 6 American aircraft carriers at the beginning of the hostilities, only 3 of them operating in the Pacific, and 3 British aircraft carriers, of which a single one operated in the Indian Ocean.

However, following the Battle of Midway, in which four Japanese carriers were sunk, the Japanese Navy suddenly found itself short of full fleet carriers, resulting in an ambitious set of projects to convert commercial and military vessels into escort carriers such as the Hiyo and Shinano, which became the largest aircraft carrier of World War II. The Navy also attempted to build a number of full fleet carriers, though most of these projects were not completed by the end of the war.

Imperial Japanese Navy - Naval Aviation

Japan began the war with a competent naval air force designed around some of the best airplanes in the world: the "Zero" was considered as the best carrier aircraft of the beginning of the war, the Mitsubishi G3M bomber was remarkable for its range and speed, and the Kawanishi H8K was considered as the world's best flying boat.^[16] The Japanese pilot corps at the beginning of the war were of high caliber as compared to their contemporaries around the world due to intense training practices and frontline experience in the Sino-Japanese War.^[17] The Navy also had a competent tactical bombing force based around the Mitsubishi G3M and G4M bombers, which astonished the world by being the first planes to sink enemy battleships under way, in the sinking of Prince of Wales and Repulse.

As the war dragged on, the Allies were quick to find weaknesses in Japanese Naval Aviation. Though most of the Japanese aircraft were characterized by having great operating ranges, 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 quickly nullified the advantages of the Japanese aircraft. Furthermore, due to delays in engine development, the Japanese Navy had great difficulty in developing new and more competitive designs during the war, resulting in the mass scale production of aircraft with known weaknesses. Following the Battle of Leyte Gulf, the Japanese Navy increasingly opted towards deploying aircraft in the kamikaze role.

Imperial Japanese Navy - Submarines

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 (Sentaka I-200), and submarines that could carry multiple bombers (WWII's largest submarine, the Sentoku I-400). These submarines were also equipped with the most advanced torpedo of the conflict, the oxygen-propelled Long Lance. A plane from one such long-range fleet submarine, I-25, conducted what is still the only 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 9th, 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^[18]. In May 1942, Type A midget submarines were used in the Attack on Sydney Harbour, and the Battle of Madagascar.

Overall, despite their technical prowesses, Japanese submarines were relatively unsuccesful. They were often used in offensive roles against warships, which were fast, maneuverable and well-defended compared to merchant ships. In 1942, Japanese submarines managed to sink two fleet carriers, one cruiser, and a few destroyers and other warships, and damage several others. They were not able to sustain these results afterwards, as Allied fleets were reinforced and became better organized. By the end of the war, submarines were instead often used to transport supplies to island garrisons. During the war, Japan managed to sink about 1 million tons of merchant shipping (184 ships), compared to 1.5 million tons for Britain (493 ships), 4.65 million tons for the US (1,079 ships) and 14.3 million tons for Germany (2,840 ships).

Early models were not very maneuverable under water, could not dive very deep, and lacked radar. (Later in the war units that were fitted with radar were in some instances sunk due to the ability of US radar sets to detect their emissions. For example, Batfish (SS-310) sunk three such equipped submarines in the span of four days). After the end of the conflict, several of Japan's most original 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 to have access to the submarines as well.

Adapted from the Wikipedia article "World War II", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki