IJN Imperial Japanese Navy / ( Nihon Kaigun )

The evolution of Japanese naval power in the five decades leading up to World War II was one of the most significant trends of the 20th Century. The Imperial Fleet was founded in the wake of the Meiji Restoration in 1868, which unified Japan. Although they lacked the infrastructure of Europe or the United States, over the next forty years the Japanese managed to construct a navy that was strong enough to decisively defeat a regional power, China, as well as a great European power, Russia.

Japan had desired to be the most powerful nation in the Far East since the 1890s. As part of that plan, Japan had to expand to acquire areas that were rich in natural resources not available in Japan and to form a protective outer ring away from the home islands. In need of raw materials and new markets, Japan fought China in the Sino-Japanese War in 1894-95. Fought in Korea and Manchuria, the Imperial Army and Imperial Navy won numerous victories, forcing China to sue for peace, in which China ceded Korea and Formosa and paid a large indemnity. In 1905, ships of the Combined Fleet, under the command of Fleet Admiral Heihachiro Togo, sailed from Sasebo to engage Russia's Baltic Fleet. Admiral Togo's victory during the Battle of Tsushima is a classic in naval history. With victories over the Russians and Chinese in the late 1890s/early 1900s, Japan had obtained Formosa, Korea, the Kuril Islands, and parts of Manchuria. As an ally at the end of World War I, Japan was mandated from Germany possession of the Marshall Islands, the Caroline Islands, and the Mariana Islands.

By 1920 Tokyo had the third largest fleet in the world. Despite continuing industrial inferiority - and with an economy that was one-ninth the size of America and heavily dependent on imports of raw materials - Japan was sufficiently powerful to directly challenge the US Navy in the Pacific by 1941.

The political emergence of the Imperial Japanese Navy between 1868 and 1922 contradicts the popular notion that the navy was a 'silent,' apolitical service. Politics, particularly budgetary politics, became the primary domestic focus - if not the overriding preoccupation - of Japan's admirals in the prewar period. As the Japanese polity broadened after 1890, navy leaders expanded their political activities to secure appropriations commensurate with the creation of a world-class blue-water fleet.

The Imperial Japanese Navy worked the Japanese body politic more successfully than almost any other organization between 1868 and 1918. It did so to transform itself from a motley collection of ships into the third most powerful navy in the world. But it also strengthened or at least further legitimated parliamentary democracy, demonstrated the potential political effectiveness of mass propaganda and pageantry, fostered nationalism, and enlarged Japan's empire toward the South Seas in perception as well as reality.

The navy's sophisticated political efforts included lobbying oligarchs, coercing cabinet ministers, forging alliances with political parties, occupying overseas territories, conducting well-orchestrated naval pageants, and launching spirited propaganda campaigns. These efforts succeeded: by 1921 naval expenditures equaled nearly 32 percent of the country's total budget. The navy made waves at sea and on shore, and in doing so significantly altered the state, society, politics, and empire in prewar Japan.

Inter-service rivalry over budget allocations between the Japanese Imperial Navy and the Imperial Army played a crucial role in the genesis of World War Two in the Pacific. The adoption of a nanshin ("southward advance") strategy by the Navy may be explained as an attempt to maximize its budget leading directly to the attack on Pearl Harbor in 1941.

The Japanese navy emulated foreign practices and evolved innovative concepts of its own. Tokyo looked to the world's most powerful fleet-the Royal Navy-as the model for modernization. Japan purchased the best naval technology and to build an impressive domestic arms industry. By the early 20th century, this process yielded a fleet that was better organized, trained, and equipped than any other in the region.

When Japan was locked in combat with Russia in 1905 and looked for asymmetric ways to defeat the superior Russian navy and started acquiring submarines. Their first five submarines were purchased from the United States. After the war with Russia, Japan developed its own submarines and continued to improve them, developing numerous types including seaplane carriers, mine warfare submarines, and midget submarines [By 1941 Japan had 65 fleet submarines, and the US Pacific Fleet had only 23].

The Washington Treaty of 1922 initially limited the Japanese to 315,000 tons of capital ships, 60% of the 525,000 tons allowed to the United States. The United States and Britain had to reduce their navies (the United States scrapped 15 battleships and cruisers that had been under construction) while the Japanese had to build up to get to their "limitation." With the stroke of a pen, Japan reduced the size of the US Navy while being allowed to increase the size of its own navy. This was followed by the 1930 London Treaty that further restricted Japanese naval strength by limiting the Japanese to 108,400 tons of heavy cruisers, 60.23% of the American heavy cruiser force, to 100,450 tons of light cruisers, 70% of the American allowance, and 52,700 tons of submarines.

The Sino-Japanese and Russo-Japanese wars spawned a unique Japanese approach to naval thought that dominated strategic and tactical discussion up to World War II. Forbidden by treaty from matching America quantitatively, Japan sought to exploit operational and technological niches to inflict disproportionate damage. Under the rubric of "using a few to conquer many," the Japanese developed comparative advantages such as long-range torpedo combat, night operations by surface units, and a tactic of outranging the U.S. fleet with subsurface, surface, and air forces. The Imperial Navy also designed and produced weapons needed to implement its strategy. During the early 1930s it deployed the first oxygen-propelled (Type 93) torpedo, whose range, speed, and payload far exceeded American and British models. In 1940 it fielded the Mitsubishi A6N "Zeke," the world's foremost carrier-based fighter.

While Japan lagged behind the United States and Great Britain in high-technology systems like radar, it built less-advanced sensors, including superior optics and searchlights. By 1940 the Japanese were much the equal of their British and American foes in training, technological innovation, and tactical proficiency.

The Imperial Japanese Navy was a pioneer in naval aviation, having commissioned the world's first built-from-the-keel-up carrier, the 'Hosho'. Throughout the 1920s and 1930s, it experimented with its carriers, perfecting their design and construction. As result, by 1941 it possessed a fantastically effective naval aviation force.

In 1907, the same year the US Navy began working on its Orange Plan for rescuing the Philippines from Japan, the United States became for the Japanese navy the "budgetary enemy." Despite the fact that Japan had been an ally during World War I, American war planning in the interwar years focused on war with Japan, and Japanese planning focused on the United States. In June 1940 Japan sought and received the French Vichy government's permission to land forces in French Indochina. Japanese Prime Minister Matsuoka Yôsuke announced the idea of the Greater East Asia Co-Prosperity Sphere (Dai-to-a Kyoeiken, variants: Dai Toa Kyoeiken, Daitoa Kyoeiken, Daitoa="Greater East Asia", Kyoeiken="Co-Prosperity Sphere") in August 1940. In September 1940 Japanese troops started occupying northern parts of French Indochina.

President Franklin D. Roosevelt's administration reacted by placing an embargo on steel and scrap iron from the United States, an event the Japanese termed an "unfriendly act." In July 1941 Japan demanded more Indochinese bases, and when Japan moved to occupy these bases, the United States, Great Britain, and the Netherlands froze Japanese assets. They also imposed an all-out embargo against Japan, including the export of oil. Japan imported all of the oil it used and had now lost access to almost all of its sources.

In August 1941 Japanese war planning increased as the military leaders realized that war with the United States was more likely everyday. In response to the American embargo, the Imperial Staff developed the "Southern Operation," a plan for capturing the industrial rich Dutch East Indies and Malaya. Japan realized this action would force the United States and Great Britain into war, so the plan also called for seizing the American-held Philippines and Guam and the British possessions of Hong Kong and Burma. Once the southern areas were secured, Japan would occupy strategic positions in the Pacific and fortify them, thus forming a tough defensive perimeter around Japan and its newly acquired resource areas. Once the perimeter was secure, Japan would try to negotiate for peace. The planners thought it would take six months to accomplish all the tasks and had to be free of interference from the American Navy during that time. Yamamoto had the plan for ensuring that the US Pacific Fleet would not interfere for six months.

On December 7, 1941, Japanese navy airplanes raided the Pearl Harbor (Hawaii) base of the United States. The American Pacific fleet was almost completely annihilated. The purpose of this action was to destroy America's main fleet and then secure sea control in the Pacific. On the same day, the Japanese army landed in Malaysia and moved towards Singapore. Japan declared war on Britain and the United States, calling this a "War of Self-Defense and Existence" [Jison Jiei Senso]. The Japanese government named this war the Great East Asian War (Daitowa Senso). After the war, the Americans banned the use of the term Greater East Asian War and therefore it is called the Pacific War (Taiheiyo Senso). Japan claimed that this was a war of self-defense by Japan, and to establish the "Great East Asian Co-Prosperity Sphere" in order to break down the stranglehold of the American and European countries. Germany and Italy also declared war against the United States.

At the opening of the Pacific War in 1941, the Japanese Combined Fleet comprised 10 battleships; 10 aircraft carriers; 38 cruisers, heavy and light; 112 destroyers; 65 submarines; and numerous auxiliary warships of lesser size. Carriers would roam the Pacific with near impunity, destroying their opponents at will.

But Japan failed to effectively harness its national resources for a war with the United States. Instead its army remained committed to a conflict in China, while its navy became increasingly enamored of an advance into Southeast Asia. In planning such a campaign, the naval leadership fell prey to circular reasoning. In the climate of worsening Japanese-American relations during the late 1930s, the Imperial Navy expected Washington to reduce or eliminate oil exports. Since the United States was its major petroleum supplier, Tokyo would be obliged to look to the Netherlands East Indies. But conquering the oil fields of the Indies would embroil Japan in a conflict with Washington that it could not win without access to those oil fields.

Japan developed the concept of "Kantai Kessen" (decisive fleet battle). Kantai Kessen assumed that any war with the United States would be primarily a naval war. Therefore, Japan wanted the fight to be near the Japanese home islands. Japanese naval planning had called for the destruction of American naval strength in a climactic gun duel between battleships - a belief firmly embraced by the other major navies of the day. As technological advances increased the operating range of submarines and aircraft, the operational theater for the interception-attrition operations and the decisive battle had moved eastward, further from Japanese home waters.Throughout the 1920s the Japanese expected the decisive battle to occur near the Ryukyu Islands. By 1940 the Japanese were planning for the decisive battle to be fought in the Marshall Islands.

Japan's traditional defensive strategy was to keep the Combined Fleet in home waters, waiting to attack the US Pacific Fleet as it sailed into the Western Pacific to liberate the Philippines. The Pacific Fleet had to be destroyed in a decisive fleet engagement to force the Americans to negotiate for peace with Japan. But Japan lacked the industrial base to support a long war against the United States. If Japan did not win in 1942 the United States would build up sufficient military strength for a powerful counterattack beginning in 1943.

The desire for a quick, decisive victory led Tokyo to neglect unglamorous but vital dimensions of operations such as logistics and personnel policy. Because its leadership assumed that a war with America would be decided by a few decisive battles, the Japanese ignored such capabilities as commerce protection and antisubmarine warfare, deficiencies which became crippling vulnerabilities in a long war of attrition.

Due to the distances involved, logistics was critical to Japan. Japan maintained its ports and navy yards throughout the home islands. They maintained larger bases at locations, including Yokosuka, Kure, Sasebo, Maizuru, and Bako. These bases could provide all required services for ships up to and including overhaul. There were many smaller yards and bases throughout the home islands that provided more limited support. Japan, like the United States, depended on forward bases for their ships. Their base on Truk Island was the most advanced, with services including refuel, rearming, and repairing. Other bases away from the home islands were Saigon and Formosa. Like the United States, Japan's ships could also refuel while under way, but it was not a practiced skill and was very rarely used. The Japanese navy had built a lot of ships, but it, like the United States, did not have enough logistics ships to properly support its fleets.

For five months after Pearl Harbor, the Imperial Japanese Navy's Combined Fleet moved across the Pacific with virtual impunity. The Battle of Coral Sea (7-8 May 1942) was the first "Carrier vs. Carrier" battle, and the first of the Pacific War's six fights between opposing aircraft carrier forces. Japan lost the light Carrier SHOHO, the large Carrier SHOKAKU was heavily damaged, and the ZUIKAKU air wing was heavily damaged. The LEXINGTON was lost to spreading fires, and YORKTOWN was damaged by bombs and returned to Pearl Harbor for repairs.

The Battle of Midway, 4-7 June 1942, represented the strategic high water mark of Japan's Pacific War. Prior to this action, Japan possessed general naval superiority over the United States and could usually choose where and when to attack. Midway cost Japan four irreplaceable fleet carriers, while only one of the three US carriers present was lost. After Midway, the two opposing fleets were essentially equals, and the United States soon took the offensive. On 7 August 1942, the first US land offensive of WWII commenced, with the US Marines landing on Guadalcanal and Tulagi, Solomon Islands. Japanese victory was impossible by late 1942, but the Japanese leadership continued fighting for another three years.

From the time of the naval battles around Gudalcanal in November 1942 until the Marianas campaign in June 1944, there were no fleet to fleet engagements of consequence. The Leyte (Philippines) landings on 20 October 1944 brought on the desperate, almost suicidal, last great sortie of the Imperial Japanese Navy. Its plan for the Battle for Leyte Gulf included a feint by a northern force of planeless heavy attack carriers to draw away the American warships protecting the landings. On 24 October 1944 planes from American carriers sank four of the Japanese carriers.

By 1945, Japan was at war with more than fifty nations -- more than half the world.

On 18 August 1945 the Japanese emissaries at Manila presented reports with detailed information concerning the Japanese Navy, names, condition, classification, and location of naval vessels, location of mined areas, shore installations, ammunition and fuel on hand; this information was incomplete due to lack of recent surveys and the fact that certain units were at sea. As early as 12 September the Imperial Japanese General Headquarters reported that all war and merchant ships, both in home ports and at sea, had been demilitarized.

In Japan, various types of suicide craft were reported in twenty-four scattered port areas 393 midget submarines, 177 human torpedoes, and 2,412 suicide surface craft.56 By October over 90 percent of this fanatical arsenal was either destroyed or placed under immediate control of the Occupation forces. As the Occupation progressed, the remaining 10 percent, together with 141 additional midget submarines, was destroyed. The general reports regarding all Japanese vessels, merchant and war, revealed 2,524 vessels of all kinds belonging to the Japanese Navy.57 By February 1946 the Second Demobilization Ministry was using 408 vessels of the former Imperial Japanese Navy-138 for repatriation, 269 for mine-sweeping, and one for transportation of fuel. Many of the ships so used were former aircraft carriers, cruisers, escorts, submarine chasers, transports, and hospital ships.

On 12 February 1948 the Far Eastern Commission belatedly ordered an early completion of the disarmament and demobilization of the Japanese Armed Forces. Combatant ships of destroyer tonnage and less were divided among the United States, United Kingdom, Soviet Russia, and China when no longer needed in the service of the Occupation. Deliveries of the several lots were based on four separate drawings held in Tokyo. During the remainder of 1947 a total of 135 former Japanese naval ships were allocated and delivered to the four major Allied Powers. In the four drawings, the U.S.S.R., the United States, and China received thirty-Four vessels each, and the United Kingdom thirty-two vessels.

The scrapping and salvage work on former Japanese warships was almost completed in the the second half of 1948. The 421 former warships in the scrapping program ranged in size from the Ise, a 40,000 ton battleship, to small torpedo boats of about twenty tons. Types of craft included aircraft carriers, destroyers, destroyer escorts, cruisers, submarines, and high speed transports. Most of these ships had suffered damage during the war but were still afloat. Steel and other metals obtained from salvage were turned over to the Japanese Government as returned enemy material to be used in peacetime industries. Scrapping costs were high due to the high cost of carbide and the low market value of the scrap.

With the completion of the scrapping of the Japanese cruiser Tone, the last of the large remaining combat vessels above the 3,000 ton class was destroyed. On 15 January 1949 the U. S. Navy reported that the scrapping program and disarmament of the Japanese naval strength was complete: the Japanese Navy was extinct.