Events leading to the attack on Pearl Harbor
Encyclopedia
A series of events led to the attack on Pearl Harbor
. War between Japan
and the United States had been a possibility that each nation's military forces planned for since the 1920s, though real tension did not begin until the 1931 invasion of Manchuria by Japan. Over the next decade, Japan expanded slowly into China
, leading to all out war between the two in 1937. In 1940 Japan invaded French Indochina in an effort to embargo all imports into China, including war supplies purchased from the U.S. This move prompted the United States to embargo all oil exports, leading the Imperial Japanese Navy
to estimate that it had less than two years of bunker oil remaining and to support the existing plans to seize oil resources in the Dutch East Indies
. Planning had been underway for some time on an attack on the "Southern Resource Area" to add it to the Greater East Asia Co-Prosperity Sphere
that Japan envisioned in the Pacific.
The Philippine islands
, at that time an American territory, were also a Japanese target. The Japanese military concluded that an invasion of the Philippines would provoke an American military response. Rather than seize and fortify the islands, and wait for the inevitable US counterattack, Japan's military leaders instead decided on the pre-emptive Pearl Harbor attack, which they assumed would negate the American forces needed for the liberation and reconquest of the islands.
Planning for the attack had begun in very early 1941, by Admiral Isoroku Yamamoto
. He finally won assent from the Naval High Command by, among other things, threatening to resign. The attack was approved in the summer at an Imperial Conference and again at a second Conference in the fall. Simultaneously over the year, pilots were trained, and ships prepared for its execution. Authority for the attack was granted at the second Imperial Conference if a diplomatic result satisfactory to Japan was not reached. After final approval by Emperor Hirohito the order to attack was issued at the beginning of December.
as part of Japan's alleged "divine right"
to unify Asia under Emperor Shōwa's rule, threatening already-established American, French, British, and Dutch colonies in Asia.
Over the course of the 1930s, Japan's increasingly expansionist policies brought it into renewed conflict with its neighbors, Russia and China (Japan had fought the First Sino-Japanese War
with China in 1894-95 and the Russo-Japanese War
with Russia in 1904-05; Japan's imperialist ambitions had a hand in precipitating both conflicts). In March 1933, Japan withdrew from the League of Nations
in response to international condemnation of its conquest of Manchuria
and subsequent establishment of the Manchukuo
puppet government. On January 15, 1936, Japan withdrew from the Second London Naval Disarmament Conference
because the United States and Great Britain refused to grant the Imperial Japanese Navy
(IJN) parity with their navies. A second full-scale war
between Japan and China began with the Marco Polo Bridge Incident
in July 1937.
Japan's 1937 attack on China was condemned by the U.S. and several members of the League of Nations including Britain, France, Australia, and the Netherlands. These states had economic and territorial interests, or formal colonies, in East
and Southeast Asia
; they were increasingly alarmed at Japan's new military power and its willingness to use it, which threatened their control in Asia. In July 1939, the U.S. terminated its 1911 commercial treaty with Japan. But these efforts failed to deter Japan from continuing its war in China, or from signing the Tripartite Pact
in 1940 with Nazi Germany
and Fascist Italy, officially forming the Axis Powers
.
Japan would take advantage of Hitler's war in Europe to advance its ambitions in the Far East. The Tripartite Pact guaranteed each of the signee nations assistance if attacked by any country then considered neutral. This message pointed directly to the United States, and gave Japan more power on the geo-political stage. The Tripartite Pact now threatened the U.S. on both shores of its continental span—Hitler and Mussolini on the Atlantic Ocean, and Japan on the Pacific. The Roosevelt administration believed the American way of life would be at risk if Europe and the Far East were to fall under military dictatorship. Roosevelt committed to help the British and the Chinese; he loaned monies and materiel
to both countries and pledged that U.S aid would be enough to ensure their survival of war. Doing so would slowly move the United States from a neutral country to one preparing for war.
On October 8, 1940, Admiral James O. Richardson, commander of the Pacific Fleet, provoked a confrontation with President Roosevelt, repeating his earlier messages to Chief of Naval Operations
Admiral Harold R. Stark
and to Secretary of the Navy
Frank Knox
—that Pearl Harbor was the wrong place for his ships. Roosevelt replied that having the fleet in Hawaii was a "restraining influence" on Japan.
Richardson asked the president if the United States was going to war. In Richardson's account the president responded:
In 1940, Japan moved into northern Indochina
. This invasion, added to the Tripartite Pact, war with China, increasing militarization, and Japan's withdrawal from the League of Nations led the U.S. to embargo
scrap metal shipments to Japan and to constrain its foreign policy actions and close the Panama Canal
to Japanese shipping. In 1941, Japan moved into southern Indochina
. The U.S. responded by freezing, on 26 July 1941, Japan's assets in the U.S. and, on 1 August 1941, embargoing all oil and gasoline exports to Japan. Oil was Japan's most crucial imported resource; more than 80 percent of Japan's oil imports at the time came from the United States To secure oil supplies, and other resources, Japanese planners had long been looking south, especially the Dutch East Indies
. The Navy was certain any attempt to seize this region would bring the U.S. into the war and was reluctant to agree with other factions' plans for invasion. The complete US oil embargo changed to the Naval view to support of expansion toward support for an invasion of the Dutch East Indies and seizure of its oil fields.
After the embargoes and the asset freezings the Ambassador of Japan in Washington and the secretary of State Cordell Hull held multiple meetings in order to discuss a solution to the Japan-American problems. No solution could be agreed upon because of three key reasons: Japan's alliance to Hitler's Germany and Mussolini's Italy through the Tripartite Pact; Japan wanted economic control and responsibility for southeast Asia; and Japan refused to leave mainland China (without Manchoukuo). Feeling the economic squeeze from the U.S embargoes, Japan had a sense of urgency, either it had to agree to Washington's demands and restore normal trade, or use force to gain access to the resources available throughout the Pacific.
, including the Japanese ambassador, Admiral Kichisaburō Nomura
, and special representative Saburō Kurusu
, had been conducting extended talks with the State Department regarding the U.S. reactions to the Japanese move into Việt Nam in the summer.
In the days before the attack, a long 14-part message was sent to the Embassy from the Foreign Office in Tokyo (encrypted with the Type 97 cryptographic machine, in a cipher named PURPLE by U.S. cryptanalysts), with instructions to deliver it to Secretary of State
Cordell Hull
at 1 p.m. Washington time. The last part arrived late Saturday night (Washington time) but due to decryption and typing delays, and to Tokyo's failure to stress the crucial necessity of the timing, Embassy personnel did not deliver the message breaking off negotiations to Secretary Hull until several hours after the attack.
The United States had decrypted the 14th part well before the Japanese Embassy managed to, and long before the Embassy managed a fair typed copy. The final part, with its instruction for the time of delivery, had been decoded that night, but was not actioned until the next morning; according to Clausen
, who also denied the claim by Bratton
that General Marshall couldn't be found (as he was out for a morning horseback ride).
It prompted General George Marshall
, Army Chief of Staff, to send that morning's warning message, with assurances that it would be received by all recipients by 1 pm Washington time. There were delays in the message sent to Hawaii because of trouble with the Army's long distance communication system, a decision not to use the Navy's parallel facilities despite an offer to permit it, and various troubles during its travels over commercial cable facilities (somehow its "urgent" marking was misplaced, adding additional hours to its travel time). It was actually delivered to General Walter Short
, by a young Japanese-American cycle messenger, several hours after the attack had ended.
The Japanese Ambassador asked for an appointment to see the Secretary at 1:00 p.m., but later telephoned and asked that the appointment be postponed to 1:45 as the Ambassador was not quite ready. The Ambassador and Mr. Kurusu arrived at the Department at 2:05 p.m. and were received by the Secretary at 2:20. The Japanese Ambassador stated that he had been instructed to deliver at 1:00 p.m. the document which he handed the Secretary, but that he was sorry that he had been delayed owing to the need of more time to decode the message. The Secretary asked why he had specified one o'clock. The Ambassador replied that he did not know but that that was his instruction. After the Secretary had read two or three pages he asked the Ambassador whether this document was presented under instructions of the Japanese Government. The Ambassador replied that it was. The Secretary as soon as he had finished reading the document turned to the Japanese Ambassador and said:
The Ambassador and Mr. Kurusu then took their leave without making any comment.
There were Japanese records, admitted into evidence during Congressional hearings on the attack after the War, that established that the Japanese government had not even written a declaration of war until hearing news of the successful attack. The two-line declaration of war was finally delivered to U.S. Ambassador Grew
in Tokyo about 10 hours after the attack was over. He was allowed to transmit it to the United States where it was received late Monday afternoon (Washington time).
In July 1941, the IJN headquarters informed Hirohito
that its reserve bunker oil would be exhausted within two years if a new source was not found. In August 1941, Japanese Prime Minister Fumimaro Konoe
proposed a summit with President Roosevelt to discuss differences. Roosevelt replied Japan must leave China before a summit meeting could be held. On September 6, 1941, at the second Imperial Conference concerning attacks on the Western colonies in Asia and Hawaii
, Japanese leaders met to consider the attack plans prepared by Imperial General Headquarters
, one day after the emperor had reprimanded General Hajime Sugiyama, the Chief of the Imperial Japanese Army (IJA)
General Staff, about the lack of success in China, and the speculated low chances of victory against the United States, British Empire
, and their allies.
Prime Minister Konoe argued for more negotiations and possible concessions to avert war. However, military leaders like Sugiyama, Minister of War
General Hideki Tōjō
, and Chief of the IJN General Staff
Admiral Osami Nagano asserted that time had run out and that additional negotiations would be pointless. They urged swift military actions against all American and European colonies in Southeast Asia and Hawaii. Tōjō opined yielding to the American demand to withdraw troops would wipe out all the fruits of the Second Sino-Japanese War, depress Army morale
, endanger Manchukuo
, and jeopardize control of Korea; hence, doing nothing was the same as defeat and a loss of face.
On October 16, 1941, Konoe resigned and proposed Prince Naruhiko Higashikuni, who was also the choice of the Army and the Navy, as his successor. Hirohito choose Hideki Tōjō
instead, worried (as he told Konoe) about having the Imperial House being held responsible for a war against Western powers.
On November 3, 1941, Nagano presented a complete plan for the attack on Pearl Harbor to Hirohito. At the Imperial Conference on 5 November, Hirohito approved the plan for a war against the United States, Great Britain and Holland, scheduled to start at the beginning of December if an acceptable diplomatic settlement were not achieved before then. The following weeks, the military regime of new Prime Minister Tōjō offered a final deal to the United States. They offered to leave only Indochina, but in return for large American economic aid. On 26 November, the so-called Hull Memorandum rejected the offer and demanded that in addition to them leaving Indochina they must leave China (without Manchoukuo) and agree to an Open Door Policy
in the Far East.
On 30 November 1941, Prince Nobuhito Takamatsu
warned his brother, Hirohito, that the Navy felt the Empire could not fight more than two years against the United States and wished to avoid war. After consulting with Kōichi Kido
(who advised him to take his time until he was convinced) and Tojo, the Emperor called Shigetarō Shimada
and Nagano who reassured him war would be successful. On December 1, Hirohito finally approved a "war against United States, Great Britain and Holland", during another Imperial Conference, to commence with a surprise attack on the US Pacific Fleet at its main forward base at Pearl Harbor in Hawaii.
On February 3, 1940, Yamamoto briefed Captain Kanji Ogawa of Naval Intelligence on the potential attack plan, asking him to start intelligence gathering on Pearl Harbor. Ogawa already had spies in Hawaii, including Japanese Consular officials with an intelligence remit, and he arranged for help from a German already living in Hawaii who was an Abwehr
agent. None had been providing much militarily useful information. He planned to add 29-year-old Ensign Takeo Yoshikawa
. By the spring of 1941, Yamamoto officially requested additional Hawaiian intelligence, and Yoshikawa boarded the liner Nitta-maru at Yokohama
. He had grown his hair longer than military length, and assumed the cover name Tadashi Morimura.
Yoshikawa began gathering intelligence in earnest by taking auto trips around the main islands, and toured Oahu in a small plane, posing as a tourist. He visited Pearl Harbor frequently, sketching the harbor and location of ships from the crest of a hill. Once, he gained access to Hickam Field
in a taxi, memorizing the number of visible planes, pilots, hangars, barracks and soldiers. He was also able to discover that Sunday was the day of the week on which the largest number of ships were likely to be in harbor, that PBY
patrol planes went out every morning and evening, and that there was an antisubmarine net in the mouth of the harbor. Information was returned to Japan in coded form in Consular communications, and by direct delivery to intelligence officers aboard Japanese ships calling at Hawaii by consulate staff.
In June 1941, German and Italian consulates were closed, and there were suggestions Japan's should be closed, as well. They were not, because they continued to provide valuable information (via MAGIC
) and neither President Roosevelt nor Secretary Hull
wanted trouble in the Pacific. Had they been closed, however, it is possible Naval General Staff, which had opposed the attack from the outset, would have called it off, since up-to-date information on the location of the Pacific Fleet, on which Yamamoto's plan depended, would no longer have been available.
Expecting war, and seeing an opportunity in the forward basing of the US Pacific Fleet
at Hawaii, the Japanese began planning in early 1941 for an attack on Pearl Harbor. For the next several months, planning, and organizing a simultaneous attack on Pearl Harbor and invasion of British and Dutch colonies to the South occupied much of the Japanese Navy's time and attention. The Pearl Harbor attack planning arose out of the Japanese expectation the U.S. would be inevitably drawn into the war after a Japanese attack against Malaya and Singapore.
The intent of a preemptive strike on Pearl Harbor was to neutralize American naval power in the Pacific, thus removing it from influencing operations against American, British, and Dutch colonies to the south. Successful attacks on colonies were judged to depend on successfully dealing with the American Pacific Fleet. Planning had long anticipated that a battle between the two Fleets would happen in Japanese home waters after the US Fleet traveled across the Pacific, under attack by submarines and other forces all the way. The US Fleet would be defeated in a climactic battle, just as had the Russian Fleet in 1905. A surprise attack posed a twofold difficulty compared to long standing expectations. First, the US Pacific Fleet was a formidable force, and would not be easy to defeat or to surprise. Second, for aerial attack, Pearl Harbor's shallow waters made using conventional air-dropped torpedoes ineffective. On the other hand, Hawaii's isolation meant a successful surprise attack could not be blocked or quickly countered by forces from the continental U.S.
Several Japanese naval officers had been impressed by the British Operation Judgement
, in which 21 obsolete Fairey Swordfish
disabled half the Regia Marina
. Admiral Yamamoto even dispatched a delegation to Italy, which concluded a larger and better-supported version of Cunningham's strike could force the U.S. Pacific Fleet to retreat to bases in California, thus giving Japan the time necessary to establish a "barrier" defense to protect Japanese control of the Dutch East Indies. The delegation returned to Japan with information about the shallow-running torpedoes Cunningham's engineers had devised.
Japanese strategists were undoubtedly influenced by Admiral Togo's surprise attack on the Russian Pacific Fleet at Port Arthur in 1905, and may have been influenced by U.S. Admiral Harry Yarnell's performance in the 1932 joint Army-Navy exercises, which simulated an invasion of Hawaii. Yarnell, as commander of the attacking force, placed his carriers northwest of Oahu and simulated an air attack. The exercise's umpires noted Yarnell's aircraft were able to inflict serious "damage" on the defenders, who for 24 hours after the attack were unable to locate his force.
Yamamoto's emphasis on destroying the American battleships was in keeping with the Mahanian doctrine shared by all major navies during this period, including the U.S. Navy
and Royal Navy
.
In a letter dated January 7, 1941 Yamamoto finally delivered a rough outline of his plan to Koshiro Oikawa
, then Navy Minister, from whom he also requested to be made Commander in Chief of the air fleet to attack Pearl Harbor.
A few weeks later, in yet another letter, this time directed at Takijiro Onishi—chief of staff of the Eleventh Air Fleet—Yamamoto requested Onishi study the technical feasibility of an attack against the American base.
After consulting first with Kosei Maeda, an expert on aerial torpedo warfare, and being told the harbor's shallow waters rendered such an attack almost impossible, Onsihi summoned Commander Minoru Genda
. After studying the original proposal put forth by Yamamoto, Genda agreed: "the plan is difficult but not impossible". During the following weeks, Genda expanded Yamamoto's original plan, highlighting the importance of it being carried out early in the morning and in total secrecy, employing an aircraft carrier force and several different types of bombing.
Although attacking the US Pacific Fleet while it was at anchor in Pearl Harbor would achieve surprise, it also carried two distinct disadvantages: The targeted ships would be sunk or damaged in very shallow water, meaning that it would be quite likely that they could be salvaged and possibly returned to duty (as six of the eight battleships eventually were); and most of the crews would survive the attack, since many would be on shore leave
or would be rescued from the harbor afterward. Despite these concerns, Yamamoto and Genda pressed ahead.
By April 1941, the Pearl Harbor plan became known as Operation Z, after the famous Z signal given by Admiral Tōgō at Tsushima. Over the summer, pilots trained in earnest near Kagoshima City on the Japanese island of Kyūshū
. Genda had chosen it because its geography and infrastructure presented most of the same problems bombers would face at Pearl Harbor. In training, each crew flew over the 5000-foot (1500 m) mountain behind Kagoshima, dove down into the city, dodging buildings and smokestacks before dropping to an altitude of 25 feet (7 m) at the piers. Bombardiers released torpedoes at a breakwater some 300 yards (270 m) away.
Yet even skimming the water did not solve the problem of torpedoes bottoming in the shallow waters of Pearl Harbor. Japanese weapons engineers created and tested modifications allowing successful shallow water drops. The effort resulted in a heavily modified version of the Type 91 torpedo
which inflicted most of the ship damage during the attack. Japanese weapons technicians also produced special armor-piercing bombs by fitting fins and release shackles to 14 and 16 inch (356 and 406 mm) naval shells. These were able to penetrate the lightly armored decks of the old battleships.
; this would provide Japan with a strategic base to shield its new empire, deny the Americans any bases beyond the west coast of North America, further isolate Australia and New Zealand, and possibly serve as a base to facilitate attacks on the American West Coast
. Although this proposal gained some support, it was ultimately dismissed for several reasons:
With an invasion ruled out, it was agreed that a massive carrier-based airstrike against Pearl Harbor to cripple the American Pacific Fleet
would be sufficient. Japanese planners knew that Hawaii, with its strategic location in the Central Pacific, would serve as a critical base from which the United States could extend its military power against Japan; However, as before, the confidence of Japanese leaders that the conflict would be over quickly and that the United States would choose to negotiate a compromise rather than fight a long, bloody war overrode this concern.
On November 26, 1941, the day the Hull note
was received from United States Secretary of State
Cordell Hull
, which the Japanese leaders saw as an unproductive and same old proposal, the carrier battle group
under the command of then Vice Admiral Chuichi Nagumo
, already assembled in Hitokappu Wan in the Kurile Islands, sortied for Hawaii under strict radio silence.
The Kido Butai, the Combined Fleet
's main carrier force of six aircraft carrier
s carriers (at the time, the most powerful carrier force with the greatest concentration of air power in the history of naval warfare), embarked 359 airplanes, organized as the First Air Fleet
. The carriers (flag
), , , , and the newest, and , had 135 Mitsubishi A6M Type 0 fighter
s (Allied codename "Zeke", commonly called "Zero"), 171 Nakajima B5N Type 97
torpedo bomber
s (Allied codename "Kate"), and 108 Aichi D3A Type 99
dive bomber
s (Allied codename "Val") aboard. Two fast battleship
s, two heavy cruiser
s, one light cruiser
, nine destroyer
s, and three fleet submarines provided escort and screening. In addition, the Advanced Expeditionary Force included 20 fleet and five two-man Ko-hyoteki
-class midget submarines, which were to gather intelligence and sink U.S. vessels attempting to flee Pearl Harbor during or soon after the attack. It also had eight oiler
s for underway fueling.
On December 1, 1941, after the striking force was en route, Chief of Staff Nagano gave a verbal directive
to commander of the Combined Fleet Admiral Isoroku Yamamoto, informing him:
Upon completion, the force was to return to Japan, re-equip, and re-deploy for "Second Phase Operations".
Finally, Order number 9, issued on 1 December 1941 by Nagano, instructed Yamamoto to crush hostile naval and air forces in Asia, the Pacific and Hawaii, promptly seize the main U.S., British, and Dutch bases in East Asia and "capture and secure the key areas of the southern regions".
On the home leg, the force was ordered to be alert for tracking and counterattacked by the Americans, and to return to the friendly base in the Marshall Islands
, rather than the Home Islands.
, Indochina
, Thailand
, or the Russian Far East
. The warnings were not specific to any area, noting only that war with Japan was expected in the near future and all commands should act accordingly. Had any of these warnings produced an active alert status in Hawaii, the attack might have been resisted more effectively, and perhaps resulted in less death and damage. On the other hand, recall of men on shore leave to the ships in harbor might have led to still more being casualties from bombs and torpedoes, or trapped in capsized ships by shut watertight doors (as the attack alert status would have required), or killed (in their obsolete aircraft) by more experienced Japanese aviators. When the attack actually arrived, Pearl Harbor was effectively unprepared: anti-aircraft weapons not manned, most ammunition locked down, anti-submarine measures not implemented (e.g., no torpedo nets in the harbor), combat air patrol not flying, available scouting aircraft not in the air at first light, Air Corps aircraft parked wingtip to wingtip to reduce sabotage risks (not ready to fly at a moment's warning), and so on.
By 1941, U.S. signals intelligence, through the Army's Signal Intelligence Service and the Office of Naval Intelligence
's OP-20-G
, had intercepted and decrypted considerable Japanese diplomatic and naval cipher
traffic, though nothing actually carrying significant information about Japanese military plans in 1940-41. Decryption and distribution of this intelligence, including such decrypts as were available, was capricious and sporadic, some of which can be accounted for by lack of resources and manpower. At best, the information available to decision makers in Washington was fragmentary, contradictory, or poorly distributed, and was almost entirely raw, without supporting analysis. It was thus, incompletely understood. Nothing in it pointed directly to an attack at Pearl Harbor, and a lack of awareness of Imperial Navy capabilities led to a widespread underlying belief Pearl Harbor was not a possible attack target. Only one message from the Hawaiian Japanese consulate (sent on 6 December), in a low level consular cipher, included mention of an attack at Pearl; it was not decrypted until 8 December.
In 1924, General William L. Mitchell produced a 324-page report warning that future wars (including with Japan) would include a new role for aircraft against existing ships and facilities. He even discussed the possibility of an air attack on Pearl Harbor, but his warnings were ignored. Navy Secretary Knox
had also appreciated the possibility of an attack at Pearl in a written analysis shortly after taking office. American commanders had been warned that tests had demonstrated shallow-water aerial torpedo attacks were possible, but no one in charge in Hawaii fully appreciated this. And a war game surprise attack against Pearl Harbor in 1932 had been judged a success and to have caused considerable damage.
Nevertheless, because it was believed Pearl Harbor had natural defenses against torpedo attack (e.g., the shallow water), the Navy did not deploy torpedo nets or baffles, which were judged to inconvenience ordinary operations. And as a result of limited numbers of long-range aircraft (including Army Air Corps bombers), reconnaissance patrols were not being made as often or as far out as required for adequate coverage against possible surprise attack; they improved considerably, with far fewer remaining planes, after the attack. The Navy had 33 PBYs in the islands, but only three on patrol at the time of the attack. Hawaii was low on the priority list for the B-17s finally becoming available for the Pacific, largely because General MacArthur in the Philippines was successfully demanding as many as could be made available to the Pacific (where they were intended as a deterrent). The British, who had contracted for them, even agreed to accept fewer to facilitate this buildup. At the time of the attack, Army and Navy were both on training status rather than operational alert.
There was also confusion about the Army's readiness status as General Short had changed local alert level designations without clearly informing Washington. Most of the Army's mobile anti-aircraft guns were secured, with ammunition locked down in armories. To avoid upsetting property owners, and in keeping with Washington's admonition not to alarm civil populations (e.g., in the late November war warning messages from the Navy and War Departments), guns were not dispersed around Pearl Harbor (i.e., on private property). Additionally, aircraft were parked on airfields to lessen the risk of sabotage
, not in anticipation of air attack, in keeping with Short's interpretation of the war warnings.
Chester Nimitz
said later, "It was God's mercy that our fleet was in Pearl Harbor on December 7, 1941.". Nimitz believed if Kimmel had discovered the Japanese approach, he would have sortied to meet them. With the American carriers absent and Kimmel's battleships at a severe disadvantage to the Japanese carriers, the likely result would have been the sinking of the American battleships at sea in deep water, where they would have been lost forever with tremendous casualties (as many as twenty thousand dead), instead of in Pearl Harbor, where the crews could easily be rescued, and six battleships ultimately raised.
Attack on Pearl Harbor
The attack on Pearl Harbor was a surprise military strike conducted by the Imperial Japanese Navy against the United States naval base at Pearl Harbor, Hawaii, on the morning of December 7, 1941...
. War between Japan
Empire of Japan
The Empire of Japan is the name of the state of Japan that existed from the Meiji Restoration on 3 January 1868 to the enactment of the post-World War II Constitution of...
and the United States had been a possibility that each nation's military forces planned for since the 1920s, though real tension did not begin until the 1931 invasion of Manchuria by Japan. Over the next decade, Japan expanded slowly into China
Republic of China
The Republic of China , commonly known as Taiwan , is a unitary sovereign state located in East Asia. Originally based in mainland China, the Republic of China currently governs the island of Taiwan , which forms over 99% of its current territory, as well as Penghu, Kinmen, Matsu and other minor...
, leading to all out war between the two in 1937. In 1940 Japan invaded French Indochina in an effort to embargo all imports into China, including war supplies purchased from the U.S. This move prompted the United States to embargo all oil exports, leading the Imperial Japanese Navy
Imperial Japanese Navy
The Imperial Japanese Navy was the navy of the Empire of Japan from 1869 until 1947, when it was dissolved following Japan's constitutional renunciation of the use of force as a means of settling international disputes...
to estimate that it had less than two years of bunker oil remaining and to support the existing plans to seize oil resources in the Dutch East Indies
Dutch East Indies
The Dutch East Indies was a Dutch colony that became modern Indonesia following World War II. It was formed from the nationalised colonies of the Dutch East India Company, which came under the administration of the Netherlands government in 1800....
. Planning had been underway for some time on an attack on the "Southern Resource Area" to add it to the Greater East Asia Co-Prosperity Sphere
Greater East Asia Co-Prosperity Sphere
The Greater East Asia Co-Prosperity Sphere was a concept created and promulgated during the Shōwa era by the government and military of the Empire of Japan. It represented the desire to create a self-sufficient "bloc of Asian nations led by the Japanese and free of Western powers"...
that Japan envisioned in the Pacific.
The Philippine islands
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
, at that time an American territory, were also a Japanese target. The Japanese military concluded that an invasion of the Philippines would provoke an American military response. Rather than seize and fortify the islands, and wait for the inevitable US counterattack, Japan's military leaders instead decided on the pre-emptive Pearl Harbor attack, which they assumed would negate the American forces needed for the liberation and reconquest of the islands.
Planning for the attack had begun in very early 1941, by Admiral Isoroku Yamamoto
Isoroku Yamamoto
was a Japanese Naval Marshal General and the commander-in-chief of the Combined Fleet during World War II, a graduate of the Imperial Japanese Naval Academy and a student of Harvard University ....
. He finally won assent from the Naval High Command by, among other things, threatening to resign. The attack was approved in the summer at an Imperial Conference and again at a second Conference in the fall. Simultaneously over the year, pilots were trained, and ships prepared for its execution. Authority for the attack was granted at the second Imperial Conference if a diplomatic result satisfactory to Japan was not reached. After final approval by Emperor Hirohito the order to attack was issued at the beginning of December.
Background to conflict
Tensions between Japan, on the one hand, and the prominent Western countries (the United States, France, Britain, and the Netherlands), on the other, increased significantly at the beginning of the increasingly militaristic Showa era, as Japanese nationalists and military leaders exerted increasing influence over government policy, adopting creation of a Greater East Asia Co-Prosperity SphereGreater East Asia Co-Prosperity Sphere
The Greater East Asia Co-Prosperity Sphere was a concept created and promulgated during the Shōwa era by the government and military of the Empire of Japan. It represented the desire to create a self-sufficient "bloc of Asian nations led by the Japanese and free of Western powers"...
as part of Japan's alleged "divine right"
Hakko ichiu
was a Japanese political slogan that became popular from the Second Sino-Japanese War to World War II, and was popularized in a speech by Prime Minister of Japan Fumimaro Konoe on January 8, 1940.-Outline:...
to unify Asia under Emperor Shōwa's rule, threatening already-established American, French, British, and Dutch colonies in Asia.
First Sino-Japanese War
The First Sino-Japanese War was fought between Qing Dynasty China and Meiji Japan, primarily over control of Korea...
with China in 1894-95 and the Russo-Japanese War
Russo-Japanese War
The Russo-Japanese War was "the first great war of the 20th century." It grew out of rival imperial ambitions of the Russian Empire and Japanese Empire over Manchuria and Korea...
with Russia in 1904-05; Japan's imperialist ambitions had a hand in precipitating both conflicts). In March 1933, Japan withdrew from the League of Nations
League of Nations
The League of Nations was an intergovernmental organization founded as a result of the Paris Peace Conference that ended the First World War. It was the first permanent international organization whose principal mission was to maintain world peace...
in response to international condemnation of its conquest of Manchuria
Manchuria
Manchuria is a historical name given to a large geographic region in northeast Asia. Depending on the definition of its extent, Manchuria usually falls entirely within the People's Republic of China, or is sometimes divided between China and Russia. The region is commonly referred to as Northeast...
and subsequent establishment of the Manchukuo
Manchukuo
Manchukuo or Manshū-koku was a puppet state in Manchuria and eastern Inner Mongolia, governed under a form of constitutional monarchy. The region was the historical homeland of the Manchus, who founded the Qing Empire in China...
puppet government. On January 15, 1936, Japan withdrew from the Second London Naval Disarmament Conference
Second London Naval Treaty
The Second London Naval Disarmament Conference opened in London, the United Kingdom, on 9 December 1935. It resulted in the Second London Naval Treaty which was signed on 25 March 1936.- Description :...
because the United States and Great Britain refused to grant the Imperial Japanese Navy
Imperial Japanese Navy
The Imperial Japanese Navy was the navy of the Empire of Japan from 1869 until 1947, when it was dissolved following Japan's constitutional renunciation of the use of force as a means of settling international disputes...
(IJN) parity with their navies. A second full-scale war
Second Sino-Japanese War
The Second Sino-Japanese War was a military conflict fought primarily between the Republic of China and the Empire of Japan. From 1937 to 1941, China fought Japan with some economic help from Germany , the Soviet Union and the United States...
between Japan and China began with the Marco Polo Bridge Incident
Marco Polo Bridge Incident
The Marco Polo Bridge Incident was a battle between the Republic of China's National Revolutionary Army and the Imperial Japanese Army, often used as the marker for the start of the Second Sino-Japanese War .The eleven-arch granite bridge, Lugouqiao, is an architecturally significant structure,...
in July 1937.
Japan's 1937 attack on China was condemned by the U.S. and several members of the League of Nations including Britain, France, Australia, and the Netherlands. These states had economic and territorial interests, or formal colonies, in East
East Asia
East Asia or Eastern Asia is a subregion of Asia that can be defined in either geographical or cultural terms...
and Southeast Asia
Southeast Asia
Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
; they were increasingly alarmed at Japan's new military power and its willingness to use it, which threatened their control in Asia. In July 1939, the U.S. terminated its 1911 commercial treaty with Japan. But these efforts failed to deter Japan from continuing its war in China, or from signing the Tripartite Pact
Tripartite Pact
The Tripartite Pact, also the Three-Power Pact, Axis Pact, Three-way Pact or Tripartite Treaty was a pact signed in Berlin, Germany on September 27, 1940, which established the Axis Powers of World War II...
in 1940 with Nazi Germany
Nazi Germany
Nazi Germany , also known as the Third Reich , but officially called German Reich from 1933 to 1943 and Greater German Reich from 26 June 1943 onward, is the name commonly used to refer to the state of Germany from 1933 to 1945, when it was a totalitarian dictatorship ruled by...
and Fascist Italy, officially forming the Axis Powers
Axis Powers
The Axis powers , also known as the Axis alliance, Axis nations, Axis countries, or just the Axis, was an alignment of great powers during the mid-20th century that fought World War II against the Allies. It began in 1936 with treaties of friendship between Germany and Italy and between Germany and...
.
Japan would take advantage of Hitler's war in Europe to advance its ambitions in the Far East. The Tripartite Pact guaranteed each of the signee nations assistance if attacked by any country then considered neutral. This message pointed directly to the United States, and gave Japan more power on the geo-political stage. The Tripartite Pact now threatened the U.S. on both shores of its continental span—Hitler and Mussolini on the Atlantic Ocean, and Japan on the Pacific. The Roosevelt administration believed the American way of life would be at risk if Europe and the Far East were to fall under military dictatorship. Roosevelt committed to help the British and the Chinese; he loaned monies and materiel
Materiel
Materiel is a term used in English to refer to the equipment and supplies in military and commercial supply chain management....
to both countries and pledged that U.S aid would be enough to ensure their survival of war. Doing so would slowly move the United States from a neutral country to one preparing for war.
On October 8, 1940, Admiral James O. Richardson, commander of the Pacific Fleet, provoked a confrontation with President Roosevelt, repeating his earlier messages to Chief of Naval Operations
Chief of Naval Operations
The Chief of Naval Operations is a statutory office held by a four-star admiral in the United States Navy, and is the most senior uniformed officer assigned to serve in the Department of the Navy. The office is a military adviser and deputy to the Secretary of the Navy...
Admiral Harold R. Stark
Harold Rainsford Stark
Harold Rainsford Stark served as an officer in the United States Navy during World War I and World War II. Stark was the US Navy's 8th Chief of Naval Operations, from August 1, 1939 to 26 March 1942....
and to Secretary of the Navy
United States Secretary of the Navy
The Secretary of the Navy of the United States of America is the head of the Department of the Navy, a component organization of the Department of Defense...
Frank Knox
Frank Knox
-External links:...
—that Pearl Harbor was the wrong place for his ships. Roosevelt replied that having the fleet in Hawaii was a "restraining influence" on Japan.
Richardson asked the president if the United States was going to war. In Richardson's account the president responded:
"At least as early as October 8, 1940, President Roosevelt believed that affairs had reached such a state that the United States would be come involved in a war with Japan. ... 'that if the Japanese attacked Thailand, or the Kra Peninsula, or the Dutch East Indies we would not enter the war, that if they even attacked the Philippines he doubted whether we would enter the war, but that they (the Japanese) could not always avoid making mistakes and that as the war continued and that area of operations expanded sooner of later they would make a mistake and we would enter the war.' ... ".
In 1940, Japan moved into northern Indochina
Indochina
The Indochinese peninsula, is a region in Southeast Asia. It lies roughly southwest of China, and east of India. The name has its origins in the French, Indochine, as a combination of the names of "China" and "India", and was adopted when French colonizers in Vietnam began expanding their territory...
. This invasion, added to the Tripartite Pact, war with China, increasing militarization, and Japan's withdrawal from the League of Nations led the U.S. to embargo
Embargo
An embargo is the partial or complete prohibition of commerce and trade with a particular country, in order to isolate it. Embargoes are considered strong diplomatic measures imposed in an effort, by the imposing country, to elicit a given national-interest result from the country on which it is...
scrap metal shipments to Japan and to constrain its foreign policy actions and close the Panama Canal
Panama Canal
The Panama Canal is a ship canal in Panama that joins the Atlantic Ocean and the Pacific Ocean and is a key conduit for international maritime trade. Built from 1904 to 1914, the canal has seen annual traffic rise from about 1,000 ships early on to 14,702 vessels measuring a total of 309.6...
to Japanese shipping. In 1941, Japan moved into southern Indochina
Indochina
The Indochinese peninsula, is a region in Southeast Asia. It lies roughly southwest of China, and east of India. The name has its origins in the French, Indochine, as a combination of the names of "China" and "India", and was adopted when French colonizers in Vietnam began expanding their territory...
. The U.S. responded by freezing, on 26 July 1941, Japan's assets in the U.S. and, on 1 August 1941, embargoing all oil and gasoline exports to Japan. Oil was Japan's most crucial imported resource; more than 80 percent of Japan's oil imports at the time came from the United States To secure oil supplies, and other resources, Japanese planners had long been looking south, especially the Dutch East Indies
Dutch East Indies
The Dutch East Indies was a Dutch colony that became modern Indonesia following World War II. It was formed from the nationalised colonies of the Dutch East India Company, which came under the administration of the Netherlands government in 1800....
. The Navy was certain any attempt to seize this region would bring the U.S. into the war and was reluctant to agree with other factions' plans for invasion. The complete US oil embargo changed to the Naval view to support of expansion toward support for an invasion of the Dutch East Indies and seizure of its oil fields.
After the embargoes and the asset freezings the Ambassador of Japan in Washington and the secretary of State Cordell Hull held multiple meetings in order to discuss a solution to the Japan-American problems. No solution could be agreed upon because of three key reasons: Japan's alliance to Hitler's Germany and Mussolini's Italy through the Tripartite Pact; Japan wanted economic control and responsibility for southeast Asia; and Japan refused to leave mainland China (without Manchoukuo). Feeling the economic squeeze from the U.S embargoes, Japan had a sense of urgency, either it had to agree to Washington's demands and restore normal trade, or use force to gain access to the resources available throughout the Pacific.
Breaking off negotiations
Part of the Japanese plan for the attack included breaking off negotiations with the United States 30 minutes before the attack began. Diplomats from the Japanese Embassy in WashingtonWashington, D.C.
Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. On July 16, 1790, the United States Congress approved the creation of a permanent national capital as permitted by the U.S. Constitution....
, including the Japanese ambassador, Admiral Kichisaburō Nomura
Kichisaburō Nomura
-External links:...
, and special representative Saburō Kurusu
Saburo Kurusu
was a Japanese career diplomat. He is remembered now as an envoy who tried to negotiate peace and understanding with the United States while Japan was secretly preparing the attack on Pearl Harbor....
, had been conducting extended talks with the State Department regarding the U.S. reactions to the Japanese move into Việt Nam in the summer.
In the days before the attack, a long 14-part message was sent to the Embassy from the Foreign Office in Tokyo (encrypted with the Type 97 cryptographic machine, in a cipher named PURPLE by U.S. cryptanalysts), with instructions to deliver it to Secretary of State
United States Secretary of State
The United States Secretary of State is the head of the United States Department of State, concerned with foreign affairs. The Secretary is a member of the Cabinet and the highest-ranking cabinet secretary both in line of succession and order of precedence...
Cordell Hull
Cordell Hull
Cordell Hull was an American politician from the U.S. state of Tennessee. He is best known as the longest-serving Secretary of State, holding the position for 11 years in the administration of President Franklin Delano Roosevelt during much of World War II...
at 1 p.m. Washington time. The last part arrived late Saturday night (Washington time) but due to decryption and typing delays, and to Tokyo's failure to stress the crucial necessity of the timing, Embassy personnel did not deliver the message breaking off negotiations to Secretary Hull until several hours after the attack.
The United States had decrypted the 14th part well before the Japanese Embassy managed to, and long before the Embassy managed a fair typed copy. The final part, with its instruction for the time of delivery, had been decoded that night, but was not actioned until the next morning; according to Clausen
Henry Clausen
Henry Christian Clausen was the author of the Clausen Report, an 800-page report on the Army Board’s Pearl Harbor Investigation. He traveled over 55,000 miles over seven months in 1945, and interviewed nearly a hundred personnel, Army, Navy, British and civilian, as a Special Investigator for the...
, who also denied the claim by Bratton
Rufus S. Bratton
Colonel Rufus S. Bratton was Chief of the Far Eastern Section of the Intelligence Branch of the Military Intelligence Division in the War Department in December 1941, when the United States entered World War II....
that General Marshall couldn't be found (as he was out for a morning horseback ride).
It prompted General George Marshall
George Marshall
George Catlett Marshall was an American military leader, Chief of Staff of the Army, Secretary of State, and the third Secretary of Defense...
, Army Chief of Staff, to send that morning's warning message, with assurances that it would be received by all recipients by 1 pm Washington time. There were delays in the message sent to Hawaii because of trouble with the Army's long distance communication system, a decision not to use the Navy's parallel facilities despite an offer to permit it, and various troubles during its travels over commercial cable facilities (somehow its "urgent" marking was misplaced, adding additional hours to its travel time). It was actually delivered to General Walter Short
Walter Short
Walter Campbell Short was a Major General in the United States Army and the U.S. military Commander responsible for the defense of U.S. military installations in Hawaii at the time of the Japanese attack on Pearl Harbor on December 7, 1941.-Early life:He was born in 1880 in Fillmore, Illinois...
, by a young Japanese-American cycle messenger, several hours after the attack had ended.
The Japanese Ambassador asked for an appointment to see the Secretary at 1:00 p.m., but later telephoned and asked that the appointment be postponed to 1:45 as the Ambassador was not quite ready. The Ambassador and Mr. Kurusu arrived at the Department at 2:05 p.m. and were received by the Secretary at 2:20. The Japanese Ambassador stated that he had been instructed to deliver at 1:00 p.m. the document which he handed the Secretary, but that he was sorry that he had been delayed owing to the need of more time to decode the message. The Secretary asked why he had specified one o'clock. The Ambassador replied that he did not know but that that was his instruction. After the Secretary had read two or three pages he asked the Ambassador whether this document was presented under instructions of the Japanese Government. The Ambassador replied that it was. The Secretary as soon as he had finished reading the document turned to the Japanese Ambassador and said:
-
- I must say that in all my conversations with you (the Japanese Ambassador) during the last nine months I have never uttered one word of untruth. This is borne out absolutely by the record. In all my fifty years of public service I have never seen a document that was more crowded with infamous falsehoods and distortions--infamous falsehoods and distortions on a scale so huge that I never imagined until today that any Government on this planet was capable of uttering them.
The Ambassador and Mr. Kurusu then took their leave without making any comment.
There were Japanese records, admitted into evidence during Congressional hearings on the attack after the War, that established that the Japanese government had not even written a declaration of war until hearing news of the successful attack. The two-line declaration of war was finally delivered to U.S. Ambassador Grew
Joseph Grew
Joseph Clark Grew was a United States diplomat and career foreign service officer. He was the chargé d'affaires at the U.S. embassy in Vienna when Austria-Hungary severed diplomatic relations with the United States on April 9, 1917. Later he was the U.S. Ambassador to Denmark 1920–1921 and U.S....
in Tokyo about 10 hours after the attack was over. He was allowed to transmit it to the United States where it was received late Monday afternoon (Washington time).
War
Hirohito
, posthumously in Japan officially called Emperor Shōwa or , was the 124th Emperor of Japan according to the traditional order, reigning from December 25, 1926, until his death in 1989. Although better known outside of Japan by his personal name Hirohito, in Japan he is now referred to...
that its reserve bunker oil would be exhausted within two years if a new source was not found. In August 1941, Japanese Prime Minister Fumimaro Konoe
Fumimaro Konoe
Prince was a politician in the Empire of Japan who served as the 34th, 38th and 39th Prime Minister of Japan and founder/leader of the Taisei Yokusankai.- Early life :...
proposed a summit with President Roosevelt to discuss differences. Roosevelt replied Japan must leave China before a summit meeting could be held. On September 6, 1941, at the second Imperial Conference concerning attacks on the Western colonies in Asia and Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
, Japanese leaders met to consider the attack plans prepared by Imperial General Headquarters
Imperial General Headquarters
The as part of the Supreme War Council was established in 1893 to coordinate efforts between the Imperial Japanese Army and Imperial Japanese Navy during wartime...
, one day after the emperor had reprimanded General Hajime Sugiyama, the Chief of the Imperial Japanese Army (IJA)
Imperial Japanese Army
-Foundation:During the Meiji Restoration, the military forces loyal to the Emperor were samurai drawn primarily from the loyalist feudal domains of Satsuma and Chōshū...
General Staff, about the lack of success in China, and the speculated low chances of victory against the United States, British Empire
British Empire
The British Empire comprised the dominions, colonies, protectorates, mandates and other territories ruled or administered by the United Kingdom. It originated with the overseas colonies and trading posts established by England in the late 16th and early 17th centuries. At its height, it was the...
, and their allies.
Prime Minister Konoe argued for more negotiations and possible concessions to avert war. However, military leaders like Sugiyama, Minister of War
Ministry of War of Japan
The , more popularly known as the Ministry of War of Japan, was cabinet-level ministry in the Empire of Japan charged with the administrative affairs of the Imperial Japanese Army...
General Hideki Tōjō
Hideki Tōjō
Hideki Tōjō was a general of the Imperial Japanese Army , the leader of the Taisei Yokusankai, and the 40th Prime Minister of Japan during most of World War II, from 17 October 1941 to 22 July 1944...
, and Chief of the IJN General Staff
Imperial Japanese Navy General Staff
The was the highest organ within the Imperial Japanese Navy. In charge of planning and operations, it was headed by an Admiral headquartered in Tokyo.-History:...
Admiral Osami Nagano asserted that time had run out and that additional negotiations would be pointless. They urged swift military actions against all American and European colonies in Southeast Asia and Hawaii. Tōjō opined yielding to the American demand to withdraw troops would wipe out all the fruits of the Second Sino-Japanese War, depress Army morale
Morale
Morale, also known as esprit de corps when discussing the morale of a group, is an intangible term used to describe the capacity of people to maintain belief in an institution or a goal, or even in oneself and others...
, endanger Manchukuo
Manchukuo
Manchukuo or Manshū-koku was a puppet state in Manchuria and eastern Inner Mongolia, governed under a form of constitutional monarchy. The region was the historical homeland of the Manchus, who founded the Qing Empire in China...
, and jeopardize control of Korea; hence, doing nothing was the same as defeat and a loss of face.
On October 16, 1941, Konoe resigned and proposed Prince Naruhiko Higashikuni, who was also the choice of the Army and the Navy, as his successor. Hirohito choose Hideki Tōjō
Hideki Tōjō
Hideki Tōjō was a general of the Imperial Japanese Army , the leader of the Taisei Yokusankai, and the 40th Prime Minister of Japan during most of World War II, from 17 October 1941 to 22 July 1944...
instead, worried (as he told Konoe) about having the Imperial House being held responsible for a war against Western powers.
Open Door Policy
The Open Door Policy is a concept in foreign affairs, which usually refers to the policy in 1899 allowing multiple Imperial powers access to China, with none of them in control of that country. As a theory, the Open Door Policy originates with British commercial practice, as was reflected in...
in the Far East.
On 30 November 1941, Prince Nobuhito Takamatsu
Prince Takamatsu
was the third son of HIM Emperor Taishō and HIM Empress Teimei and a younger brother of the HIM Emperor Shōwa . He became heir to the Takamatsu-no-miya , one of the four shinnōke or branches of the imperial family entitled to inherit the Chrysanthemum throne in default of a direct heir...
warned his brother, Hirohito, that the Navy felt the Empire could not fight more than two years against the United States and wished to avoid war. After consulting with Kōichi Kido
Koichi Kido
Marquis served as Lord Keeper of the Privy Seal from 1940 to 1945, and was the closest advisor to Emperor Showa throughout World War II.Kido was the grandson of Kido Takayoshi, one of the leaders of the Meiji Restoration...
(who advised him to take his time until he was convinced) and Tojo, the Emperor called Shigetarō Shimada
Shigetaro Shimada
was an admiral in the Imperial Japanese Navy during World War II. He also served as Navy Minister-Biography:A native of Tokyo, Shimada graduated from the 32nd class of the Imperial Japanese Naval Academy in 1904...
and Nagano who reassured him war would be successful. On December 1, Hirohito finally approved a "war against United States, Great Britain and Holland", during another Imperial Conference, to commence with a surprise attack on the US Pacific Fleet at its main forward base at Pearl Harbor in Hawaii.
Intelligence gathering
Abwehr
The Abwehr was a German military intelligence organisation from 1921 to 1944. The term Abwehr was used as a concession to Allied demands that Germany's post-World War I intelligence activities be for "defensive" purposes only...
agent. None had been providing much militarily useful information. He planned to add 29-year-old Ensign Takeo Yoshikawa
Takeo Yoshikawa
was a Japanese spy in Hawaii before the attack on Pearl Harbor on December 7, 1941.-Early career:A 1933 graduate of the Imperial Japanese Naval Academy at Etajima , Yoshikawa served briefly at sea aboard the armored cruiser Asama as well as submarines and had begun training as a naval pilot near...
. By the spring of 1941, Yamamoto officially requested additional Hawaiian intelligence, and Yoshikawa boarded the liner Nitta-maru at Yokohama
Yokohama
is the capital city of Kanagawa Prefecture and the second largest city in Japan by population after Tokyo and most populous municipality of Japan. It lies on Tokyo Bay, south of Tokyo, in the Kantō region of the main island of Honshu...
. He had grown his hair longer than military length, and assumed the cover name Tadashi Morimura.
Yoshikawa began gathering intelligence in earnest by taking auto trips around the main islands, and toured Oahu in a small plane, posing as a tourist. He visited Pearl Harbor frequently, sketching the harbor and location of ships from the crest of a hill. Once, he gained access to Hickam Field
Hickam Air Force Base
Hickam Field, re-named Hickam Air Force Base in 1948, was a United States Air Force facility now part of Joint Base Pearl Harbor-Hickam, named in honor of aviation pioneer Lt Col Horace Meek Hickam.- History :...
in a taxi, memorizing the number of visible planes, pilots, hangars, barracks and soldiers. He was also able to discover that Sunday was the day of the week on which the largest number of ships were likely to be in harbor, that PBY
PBY Catalina
The Consolidated PBY Catalina was an American flying boat of the 1930s and 1940s produced by Consolidated Aircraft. It was one of the most widely used multi-role aircraft of World War II. PBYs served with every branch of the United States Armed Forces and in the air forces and navies of many other...
patrol planes went out every morning and evening, and that there was an antisubmarine net in the mouth of the harbor. Information was returned to Japan in coded form in Consular communications, and by direct delivery to intelligence officers aboard Japanese ships calling at Hawaii by consulate staff.
In June 1941, German and Italian consulates were closed, and there were suggestions Japan's should be closed, as well. They were not, because they continued to provide valuable information (via MAGIC
Magic (cryptography)
Magic was an Allied cryptanalysis project during World War II. It involved the United States Army's Signals Intelligence Section and the United States Navy's Communication Special Unit. -Codebreaking:...
) and neither President Roosevelt nor Secretary Hull
Cordell Hull
Cordell Hull was an American politician from the U.S. state of Tennessee. He is best known as the longest-serving Secretary of State, holding the position for 11 years in the administration of President Franklin Delano Roosevelt during much of World War II...
wanted trouble in the Pacific. Had they been closed, however, it is possible Naval General Staff, which had opposed the attack from the outset, would have called it off, since up-to-date information on the location of the Pacific Fleet, on which Yamamoto's plan depended, would no longer have been available.
Planning
United States Pacific Fleet
The United States Pacific Fleet is a Pacific Ocean theater-level component command of the United States Navy that provides naval resources under the operational control of the United States Pacific Command. Its home port is at Pearl Harbor Naval Base, Hawaii. It is commanded by Admiral Patrick M...
at Hawaii, the Japanese began planning in early 1941 for an attack on Pearl Harbor. For the next several months, planning, and organizing a simultaneous attack on Pearl Harbor and invasion of British and Dutch colonies to the South occupied much of the Japanese Navy's time and attention. The Pearl Harbor attack planning arose out of the Japanese expectation the U.S. would be inevitably drawn into the war after a Japanese attack against Malaya and Singapore.
The intent of a preemptive strike on Pearl Harbor was to neutralize American naval power in the Pacific, thus removing it from influencing operations against American, British, and Dutch colonies to the south. Successful attacks on colonies were judged to depend on successfully dealing with the American Pacific Fleet. Planning had long anticipated that a battle between the two Fleets would happen in Japanese home waters after the US Fleet traveled across the Pacific, under attack by submarines and other forces all the way. The US Fleet would be defeated in a climactic battle, just as had the Russian Fleet in 1905. A surprise attack posed a twofold difficulty compared to long standing expectations. First, the US Pacific Fleet was a formidable force, and would not be easy to defeat or to surprise. Second, for aerial attack, Pearl Harbor's shallow waters made using conventional air-dropped torpedoes ineffective. On the other hand, Hawaii's isolation meant a successful surprise attack could not be blocked or quickly countered by forces from the continental U.S.
Several Japanese naval officers had been impressed by the British Operation Judgement
Battle of Taranto
The naval Battle of Taranto took place on the night of 11–12 November 1940 during the Second World War. The Royal Navy launched the first all-aircraft ship-to-ship naval attack in history, flying a small number of obsolescent biplane torpedo bombers from an aircraft carrier in the Mediterranean Sea...
, in which 21 obsolete Fairey Swordfish
Fairey Swordfish
The Fairey Swordfish was a torpedo bomber built by the Fairey Aviation Company and used by the Fleet Air Arm of the Royal Navy during the Second World War...
disabled half the Regia Marina
Regia Marina
The Regia Marina dates from the proclamation of the Kingdom of Italy in 1861 after Italian unification...
. Admiral Yamamoto even dispatched a delegation to Italy, which concluded a larger and better-supported version of Cunningham's strike could force the U.S. Pacific Fleet to retreat to bases in California, thus giving Japan the time necessary to establish a "barrier" defense to protect Japanese control of the Dutch East Indies. The delegation returned to Japan with information about the shallow-running torpedoes Cunningham's engineers had devised.
Japanese strategists were undoubtedly influenced by Admiral Togo's surprise attack on the Russian Pacific Fleet at Port Arthur in 1905, and may have been influenced by U.S. Admiral Harry Yarnell's performance in the 1932 joint Army-Navy exercises, which simulated an invasion of Hawaii. Yarnell, as commander of the attacking force, placed his carriers northwest of Oahu and simulated an air attack. The exercise's umpires noted Yarnell's aircraft were able to inflict serious "damage" on the defenders, who for 24 hours after the attack were unable to locate his force.
Yamamoto's emphasis on destroying the American battleships was in keeping with the Mahanian doctrine shared by all major navies during this period, including the U.S. Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
and Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
.
Koshiro Oikawa
was an admiral in the Imperial Japanese Navy and Naval Minister during World War II.-Biography:Oikawa was born into a wealthy family in rural Koshi County, Niigata Prefecture, but was raised in Morioka city, Iwate prefecture in northern Japan....
, then Navy Minister, from whom he also requested to be made Commander in Chief of the air fleet to attack Pearl Harbor.
A few weeks later, in yet another letter, this time directed at Takijiro Onishi—chief of staff of the Eleventh Air Fleet—Yamamoto requested Onishi study the technical feasibility of an attack against the American base.
After consulting first with Kosei Maeda, an expert on aerial torpedo warfare, and being told the harbor's shallow waters rendered such an attack almost impossible, Onsihi summoned Commander Minoru Genda
Minoru Genda
was a well-known Japanese military aviator and politician. He is best known for planning the Pearl Harbor attack.- Early life :Minoru Genda was the second son of a farmer from Hiroshima. Two brothers were graduates of Tokyo University, another brother graduated from Chiba Medical College, and his...
. After studying the original proposal put forth by Yamamoto, Genda agreed: "the plan is difficult but not impossible". During the following weeks, Genda expanded Yamamoto's original plan, highlighting the importance of it being carried out early in the morning and in total secrecy, employing an aircraft carrier force and several different types of bombing.
Although attacking the US Pacific Fleet while it was at anchor in Pearl Harbor would achieve surprise, it also carried two distinct disadvantages: The targeted ships would be sunk or damaged in very shallow water, meaning that it would be quite likely that they could be salvaged and possibly returned to duty (as six of the eight battleships eventually were); and most of the crews would survive the attack, since many would be on shore leave
Shore leave
Shore leave is the leave that professional sailors get to spend on dry land. It is culturally infamous for its excess. Sailors without family obligations and with basic lodging needs provided aboard ship may spend their wages for the journey in a brief period of extravagance ashore and return to...
or would be rescued from the harbor afterward. Despite these concerns, Yamamoto and Genda pressed ahead.
By April 1941, the Pearl Harbor plan became known as Operation Z, after the famous Z signal given by Admiral Tōgō at Tsushima. Over the summer, pilots trained in earnest near Kagoshima City on the Japanese island of Kyūshū
Kyushu
is the third largest island of Japan and most southwesterly of its four main islands. Its alternate ancient names include , , and . The historical regional name is referred to Kyushu and its surrounding islands....
. Genda had chosen it because its geography and infrastructure presented most of the same problems bombers would face at Pearl Harbor. In training, each crew flew over the 5000-foot (1500 m) mountain behind Kagoshima, dove down into the city, dodging buildings and smokestacks before dropping to an altitude of 25 feet (7 m) at the piers. Bombardiers released torpedoes at a breakwater some 300 yards (270 m) away.
Yet even skimming the water did not solve the problem of torpedoes bottoming in the shallow waters of Pearl Harbor. Japanese weapons engineers created and tested modifications allowing successful shallow water drops. The effort resulted in a heavily modified version of the Type 91 torpedo
Type 91 torpedo
The Type 91 was an aerial torpedo of the Imperial Japanese Navy which was designed to be launched from an aircraft. It was used in the naval battles of carrier task forces in World War II.The Type 91 aerial torpedo rev.2 won the admiration of the world...
which inflicted most of the ship damage during the attack. Japanese weapons technicians also produced special armor-piercing bombs by fitting fins and release shackles to 14 and 16 inch (356 and 406 mm) naval shells. These were able to penetrate the lightly armored decks of the old battleships.
Concept of a Japanese Invasion of Hawaii
At several stages during 1941, Japan's military leaders, including Yamamoto and Genda, gave some thought to trying to launch an invasion to seize control of the Hawaiian IslandsHawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
; this would provide Japan with a strategic base to shield its new empire, deny the Americans any bases beyond the west coast of North America, further isolate Australia and New Zealand, and possibly serve as a base to facilitate attacks on the American West Coast
West Coast of the United States
West Coast or Pacific Coast are terms for the westernmost coastal states of the United States. The term most often refers to the states of California, Oregon, and Washington. Although not part of the contiguous United States, Alaska and Hawaii do border the Pacific Ocean but can't be included in...
. Although this proposal gained some support, it was ultimately dismissed for several reasons:
- Japan's ground forces, logistics and resources were already fully committed, not only to the Second Sino-Japanese WarSecond Sino-Japanese WarThe Second Sino-Japanese War was a military conflict fought primarily between the Republic of China and the Empire of Japan. From 1937 to 1941, China fought Japan with some economic help from Germany , the Soviet Union and the United States...
but also for offensives in Southeast Asia that were planned to occur immediately almost simultaneously with the Pearl Harbor attack. - The Imperial Japanese ArmyImperial Japanese Army-Foundation:During the Meiji Restoration, the military forces loyal to the Emperor were samurai drawn primarily from the loyalist feudal domains of Satsuma and Chōshū...
(IJA), which insisted that it needed to focus on operations in China and the Southeast Asia, refused to supply any troops. - Most of the Combined Fleet's senior officers, in particular Fleet Admiral Osami Nagano (永野修身), believed that an invasion of Hawaii was too risky.
With an invasion ruled out, it was agreed that a massive carrier-based airstrike against Pearl Harbor to cripple the American Pacific Fleet
United States Pacific Fleet
The United States Pacific Fleet is a Pacific Ocean theater-level component command of the United States Navy that provides naval resources under the operational control of the United States Pacific Command. Its home port is at Pearl Harbor Naval Base, Hawaii. It is commanded by Admiral Patrick M...
would be sufficient. Japanese planners knew that Hawaii, with its strategic location in the Central Pacific, would serve as a critical base from which the United States could extend its military power against Japan; However, as before, the confidence of Japanese leaders that the conflict would be over quickly and that the United States would choose to negotiate a compromise rather than fight a long, bloody war overrode this concern.
The strike force
Hull note
The Hull note or officially Outline of Proposed Basis for Agreement Between the United States and Japan was the final proposal delivered to the Empire of Japan by the United States before the attack on Pearl Harbor and the declaration of war between the two nations...
was received from United States Secretary of State
United States Secretary of State
The United States Secretary of State is the head of the United States Department of State, concerned with foreign affairs. The Secretary is a member of the Cabinet and the highest-ranking cabinet secretary both in line of succession and order of precedence...
Cordell Hull
Cordell Hull
Cordell Hull was an American politician from the U.S. state of Tennessee. He is best known as the longest-serving Secretary of State, holding the position for 11 years in the administration of President Franklin Delano Roosevelt during much of World War II...
, which the Japanese leaders saw as an unproductive and same old proposal, the carrier battle group
Carrier battle group
A carrier battle group consists of an aircraft carrier and its escorts, together composing the group. The first naval task forces built around carriers appeared just prior to and during World War II. The Imperial Japanese Navy was the first to assemble a large number of carriers into a single...
under the command of then Vice Admiral Chuichi Nagumo
Chuichi Nagumo
was a Japanese admiral in the Imperial Japanese Navy during World War II and one time commander of the Kido Butai . He committed suicide during the Battle of Saipan.-Early life:...
, already assembled in Hitokappu Wan in the Kurile Islands, sortied for Hawaii under strict radio silence.
The Kido Butai, the Combined Fleet
Combined Fleet
The was the main ocean-going component of the Imperial Japanese Navy. The Combined Fleet was not a standing force, but a temporary force formed for the duration of a conflict or major naval maneuvers from various units normally under separate commands in peacetime....
's main carrier force of six aircraft carrier
Aircraft carrier
An aircraft carrier is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations...
s carriers (at the time, the most powerful carrier force with the greatest concentration of air power in the history of naval warfare), embarked 359 airplanes, organized as the First Air Fleet
1st Air Fleet of the Imperial Japanese Navy
The Imperial Japanese Navy at the beginning of World War II contained the world's largest carrier fleet. At the centre, was the 1st Air Fleet which was a grouping of naval aircraft and aircraft carriers...
. The carriers (flag
Flagship
A flagship is a vessel used by the commanding officer of a group of naval ships, reflecting the custom of its commander, characteristically a flag officer, flying a distinguishing flag...
), , , , and the newest, and , had 135 Mitsubishi A6M Type 0 fighter
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...
s (Allied codename "Zeke", commonly called "Zero"), 171 Nakajima B5N Type 97
Nakajima B5N
|-See also:-References:NotesBibliography* Bridgwater, H.C. and Peter Scott. Combat Colours Number 4: Pearl Harbor and Beyond, December 1941 to May 1942. Luton, Bedfordshire, UK: Guideline Publications, 2001. ISBN 0-9539040-6-7....
torpedo bomber
Torpedo bomber
A torpedo bomber is a bomber aircraft designed primarily to attack ships with aerial torpedoes which could also carry out conventional bombings. Torpedo bombers existed almost exclusively prior to and during World War II when they were an important element in many famous battles, notably the...
s (Allied codename "Kate"), and 108 Aichi D3A Type 99
Aichi D3A
The , Allied reporting name "Val") was a World War II carrier-borne dive bomber of the Imperial Japanese Navy . It was the primary dive bomber in the Imperial Japanese Navy, and participated in almost all actions, including Pearl Harbor....
dive bomber
Dive bomber
A dive bomber is a bomber aircraft that dives directly at its targets in order to provide greater accuracy for the bomb it drops. Diving towards the target reduces the distance the bomb has to fall, which is the primary factor in determining the accuracy of the drop...
s (Allied codename "Val") aboard. Two fast battleship
Battleship
A battleship is a large armored warship with a main battery consisting of heavy caliber guns. Battleships were larger, better armed and armored than cruisers and destroyers. As the largest armed ships in a fleet, battleships were used to attain command of the sea and represented the apex of a...
s, two heavy cruiser
Heavy cruiser
The heavy cruiser was a type of cruiser, a naval warship designed for long range, high speed and an armament of naval guns roughly 203mm calibre . The heavy cruiser can be seen as a lineage of ship design from 1915 until 1945, although the term 'heavy cruiser' only came into formal use in 1930...
s, one light cruiser
Light cruiser
A light cruiser is a type of small- or medium-sized warship. The term is a shortening of the phrase "light armored cruiser", describing a small ship that carried armor in the same way as an armored cruiser: a protective belt and deck...
, nine destroyer
Destroyer
In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...
s, and three fleet submarines provided escort and screening. In addition, the Advanced Expeditionary Force included 20 fleet and five two-man Ko-hyoteki
Ko-hyoteki class submarine
The class was a class of Japanese midget submarines used during World War II. They had hull numbers but no names. For simplicity, they are most often referred to by the hull number of the mother submarine...
-class midget submarines, which were to gather intelligence and sink U.S. vessels attempting to flee Pearl Harbor during or soon after the attack. It also had eight oiler
Tanker (ship)
A tanker is a ship designed to transport liquids in bulk. Major types of tankship include the oil tanker, the chemical tanker, and the liquefied natural gas carrier.-Background:...
s for underway fueling.
The execute order
Directive
Directive may refer to:* Directive , a legislative act of the European Union* Directive , a highly-acclaimed poem by Robert Frost...
to commander of the Combined Fleet Admiral Isoroku Yamamoto, informing him:
Upon completion, the force was to return to Japan, re-equip, and re-deploy for "Second Phase Operations".
Finally, Order number 9, issued on 1 December 1941 by Nagano, instructed Yamamoto to crush hostile naval and air forces in Asia, the Pacific and Hawaii, promptly seize the main U.S., British, and Dutch bases in East Asia and "capture and secure the key areas of the southern regions".
On the home leg, the force was ordered to be alert for tracking and counterattacked by the Americans, and to return to the friendly base in the Marshall Islands
Marshall Islands
The Republic of the Marshall Islands , , is a Micronesian nation of atolls and islands in the middle of the Pacific Ocean, just west of the International Date Line and just north of the Equator. As of July 2011 the population was 67,182...
, rather than the Home Islands.
Lack of preparation
U.S. civil and military intelligence had, amongst them, good information suggesting additional Japanese aggression throughout the summer and fall before the attack. At the time, no reports specifically indicated an attack against Pearl Harbor. Public press reports during summer and fall, including Hawaiian newspapers, contained extensive reports on the growing tension in the Pacific. Late in November, all Pacific commands, including both the Navy and Army in Hawaii, were separately and explicitly warned war with Japan was expected in the very near future, and it was preferred that Japan make the first hostile act as they were apparently preparing to do. It was felt that war would most probably start with attacks in the Far East: the PhilippinesPhilippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
, Indochina
Indochina
The Indochinese peninsula, is a region in Southeast Asia. It lies roughly southwest of China, and east of India. The name has its origins in the French, Indochine, as a combination of the names of "China" and "India", and was adopted when French colonizers in Vietnam began expanding their territory...
, Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
, or the Russian Far East
Russian Far East
Russian Far East is a term that refers to the Russian part of the Far East, i.e., extreme east parts of Russia, between Lake Baikal in Eastern Siberia and the Pacific Ocean...
. The warnings were not specific to any area, noting only that war with Japan was expected in the near future and all commands should act accordingly. Had any of these warnings produced an active alert status in Hawaii, the attack might have been resisted more effectively, and perhaps resulted in less death and damage. On the other hand, recall of men on shore leave to the ships in harbor might have led to still more being casualties from bombs and torpedoes, or trapped in capsized ships by shut watertight doors (as the attack alert status would have required), or killed (in their obsolete aircraft) by more experienced Japanese aviators. When the attack actually arrived, Pearl Harbor was effectively unprepared: anti-aircraft weapons not manned, most ammunition locked down, anti-submarine measures not implemented (e.g., no torpedo nets in the harbor), combat air patrol not flying, available scouting aircraft not in the air at first light, Air Corps aircraft parked wingtip to wingtip to reduce sabotage risks (not ready to fly at a moment's warning), and so on.
By 1941, U.S. signals intelligence, through the Army's Signal Intelligence Service and the Office of Naval Intelligence
Office of Naval Intelligence
The Office of Naval Intelligence was established in the United States Navy in 1882. ONI was established to "seek out and report" on the advancements in other nations' navies. Its headquarters are at the National Maritime Intelligence Center in Suitland, Maryland...
's OP-20-G
OP-20-G
OP-20-G or "Office of Chief Of Naval Operations , 20th Division of the Office of Naval Communications, G Section / Communications Security", was the US Navy's signals intelligence and cryptanalysis group during World War II. Its mission was to intercept, decrypt, and analyze naval communications...
, had intercepted and decrypted considerable Japanese diplomatic and naval cipher
Cipher
In cryptography, a cipher is an algorithm for performing encryption or decryption — a series of well-defined steps that can be followed as a procedure. An alternative, less common term is encipherment. In non-technical usage, a “cipher” is the same thing as a “code”; however, the concepts...
traffic, though nothing actually carrying significant information about Japanese military plans in 1940-41. Decryption and distribution of this intelligence, including such decrypts as were available, was capricious and sporadic, some of which can be accounted for by lack of resources and manpower. At best, the information available to decision makers in Washington was fragmentary, contradictory, or poorly distributed, and was almost entirely raw, without supporting analysis. It was thus, incompletely understood. Nothing in it pointed directly to an attack at Pearl Harbor, and a lack of awareness of Imperial Navy capabilities led to a widespread underlying belief Pearl Harbor was not a possible attack target. Only one message from the Hawaiian Japanese consulate (sent on 6 December), in a low level consular cipher, included mention of an attack at Pearl; it was not decrypted until 8 December.
In 1924, General William L. Mitchell produced a 324-page report warning that future wars (including with Japan) would include a new role for aircraft against existing ships and facilities. He even discussed the possibility of an air attack on Pearl Harbor, but his warnings were ignored. Navy Secretary Knox
Knox
- People :* Knox , including list of persons with the surname* John Knox, Presbyterian reformer* Henry Knox, American Revolutionary War hero and namesake of Fort Knox...
had also appreciated the possibility of an attack at Pearl in a written analysis shortly after taking office. American commanders had been warned that tests had demonstrated shallow-water aerial torpedo attacks were possible, but no one in charge in Hawaii fully appreciated this. And a war game surprise attack against Pearl Harbor in 1932 had been judged a success and to have caused considerable damage.
Nevertheless, because it was believed Pearl Harbor had natural defenses against torpedo attack (e.g., the shallow water), the Navy did not deploy torpedo nets or baffles, which were judged to inconvenience ordinary operations. And as a result of limited numbers of long-range aircraft (including Army Air Corps bombers), reconnaissance patrols were not being made as often or as far out as required for adequate coverage against possible surprise attack; they improved considerably, with far fewer remaining planes, after the attack. The Navy had 33 PBYs in the islands, but only three on patrol at the time of the attack. Hawaii was low on the priority list for the B-17s finally becoming available for the Pacific, largely because General MacArthur in the Philippines was successfully demanding as many as could be made available to the Pacific (where they were intended as a deterrent). The British, who had contracted for them, even agreed to accept fewer to facilitate this buildup. At the time of the attack, Army and Navy were both on training status rather than operational alert.
There was also confusion about the Army's readiness status as General Short had changed local alert level designations without clearly informing Washington. Most of the Army's mobile anti-aircraft guns were secured, with ammunition locked down in armories. To avoid upsetting property owners, and in keeping with Washington's admonition not to alarm civil populations (e.g., in the late November war warning messages from the Navy and War Departments), guns were not dispersed around Pearl Harbor (i.e., on private property). Additionally, aircraft were parked on airfields to lessen the risk of sabotage
Sabotage
Sabotage is a deliberate action aimed at weakening another entity through subversion, obstruction, disruption, or destruction. In a workplace setting, sabotage is the conscious withdrawal of efficiency generally directed at causing some change in workplace conditions. One who engages in sabotage is...
, not in anticipation of air attack, in keeping with Short's interpretation of the war warnings.
Chester Nimitz
Chester Nimitz
Fleet Admiral Chester William Nimitz, GCB, USN was a five-star admiral in the United States Navy. He held the dual command of Commander in Chief, United States Pacific Fleet , for U.S. naval forces and Commander in Chief, Pacific Ocean Areas , for U.S...
said later, "It was God's mercy that our fleet was in Pearl Harbor on December 7, 1941.". Nimitz believed if Kimmel had discovered the Japanese approach, he would have sortied to meet them. With the American carriers absent and Kimmel's battleships at a severe disadvantage to the Japanese carriers, the likely result would have been the sinking of the American battleships at sea in deep water, where they would have been lost forever with tremendous casualties (as many as twenty thousand dead), instead of in Pearl Harbor, where the crews could easily be rescued, and six battleships ultimately raised.