Plan to Attack Pearl Harbor - History

Plan to Attack Pearl Harbor - History

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The Commander and Chief of the Japanese Navy Admiral Isorku Yaamoto developed a plan to launch a surprise attack against the US fleet at Pearl Harbor. The successful British attack on Italian fleet at Taranto served as a model for the Japanese attack.

While negotiations between the US continued the Japanese planned their attack. They were aided by excellent intelligence information supplied by their consulate officials in Hawaii. On November 26, 1941 the Japanese fleet of 23 warships weighed anchor-destination Hawaii. Their plan; a surprise attack on the American fleet on the morning of December 7th by torpedo and dive bombers on the American fleet. The attack was to be combined with an attack by midget submarines on the fleet.

Attack on Pearl Harbor Lesson Plan

After reading the book, students will practice using primary-source material for research.

Quick links to lesson materials:

Teach This Lesson

About the Book

After reading Attack on Pearl Harbor: The True Story of the Day America Entered World War II, you too will remember that fateful day in American history — December 7, 1941. Weaving together dramatic eyewitness accounts of both American and Japanese servicemen, as well as children like Peter Nottage, who watched in horror as bombs dropped over Kaneohe Bay, Shelley Tanaka creates a tapestry of terrifying and heroic memories of war. Reading Level: 5.3


  • Learn how authors use primary-source material for research and development of nonfiction material
  • Enhance their understandings of varying viewpoints
  • Produce a response to literature

Before Reading

Take students on an Observation Walk around the school's neighborhood. Bring pens/pencils and notebooks for writing. Ask students to observe someone or something very carefully and closely. What do they see? They should describe everything in detail and record their observations.

When students return to class, invite them to share their observation notes. Discuss what skills and personality traits you need to be a keen observer. Introduce the term "eyewitness account" — a firsthand retelling of an event. Explain that the book Attack on Pearl Harbor tells the story of that historical event through many different eyewitness accounts.

Discussion Questions

  1. How do different eyewitnesses view the events of Pearl Harbor? For example, compare and contrast Peter Nottage, a young boy, with Japanese naval officer Commander Fuchida.
  2. How did the events of Pearl Harbor change the lives of the eyewitnesses?
  3. Out of the four eyewitnesses, whose perspective do you find most compelling? Why? Use examples from the book to support your opinion.
  4. What did you find most surprising about the book?

Writing Activity

This works best as a Final Writing project.

Step 1: After reading Attack on Pearl Harbor, have your students choose one of the eyewitnesses featured in the book: Peter Nottage, Commander Fuchida, Kazuo Sakamaki, or George DeLong. They should consider who might tell the most interesting story of the attack and offer a fresh perspective on the historical event.

Step 2: Students should reread sections of the book that relate to their person and mark with sticky notes for quick reference, then take notes on important facts and details in those sections.

Step 3: Explain to students that these notes will be used to write an Eyewitness Account from the point of view of the person they selected in Step 1. Briefly discuss point of view — what is it? How is it used in literature? How will the point of view of your students' pieces differ from Tanaka's retelling in the book?

Step 4: Students can write their Eyewitness Accounts in different formats — diary, letter, interior monologue (thoughts inside a person's head), dialogue, etc. Remind students to focus on what the person saw, heard, thought, and felt during the event. Also ask students to add their own creative details to enhance their writing.

Step 5: During the writing process, students should draft, revise, edit, and finally publish their Eyewitness Accounts.

Extension Activity

Students perform their Eyewitness Accounts as dramatic monologues. Use costumes and props for a more theatrical presentation.

Recommended Books for Comparing and Contrasting

Remember Pearl Harbor: American and Japanese Survivors Tell Their Stories
By Thomas B. Allen and Robert D. Ballard

First-person accounts from both Japanese and American survivors, combined with striking photos help remind readers why it is necessary to remember Pearl Harbor.

Pearl Harbor Child
By Dorinda Nicholson

A personal account of Pearl Harbor, this time told from the viewpoint of Dorinda, who was only a six-year-old girl when the bombs fell.

Pearl Harbor: The Day of Infamy — An Illustrated History
By Dan van der Vat

Retells the story of Pearl Harbor through paintings, photographs, and testimonials.

The Way It Was: Pearl Harbor — The Original Photographs
By Donald M. Goldstein, Katharine V. Dillon, and J. Michael Wenger

Relive the date that will forever live in infamy through photos and simple narrative.


The McCollum memo contained an eight-part plan to counter rising Japanese power over East Asia, introduced with this short, explicit paragraph: [7]

It is not believed that in the present state of political opinion the United States government is capable of declaring war against Japan without more ado and it is barely possible that vigorous action on our part might lead the Japanese to modify their attitude. Therefore the following course of action is suggested: A. Make an arrangement with Britain for the use of British bases in the Pacific, particularly Singapore B. Make an arrangement with the Netherlands for the use of base facilities and acquisition of supplies in the Dutch East Indies C. Give all possible aid to the Chinese government of Chiang-Kai-Shek D. Send a division of long range heavy cruisers to the Orient, Philippines, or Singapore E. Send two divisions of submarines to the Orient F. Keep the main strength of the U.S. fleet now in the Pacific[,] in the vicinity of the Hawaiian Islands G. Insist that the Dutch refuse to grant Japanese demands for undue economic concessions, particularly oil H. Completely embargo all U.S. trade with Japan, in collaboration with a similar embargo imposed by the British Empire If by these means Japan could be led to commit an overt act of war, so much the better. At all events we must be fully prepared to accept the threat of war.

The memo was read and appended by Captain Knox, who, despite being seemingly reluctant to "precipitate anything in the Orient", ultimately concurs. Specifically, he wrote (page 6):

It is unquestionably to our interest that Britain be not licked – just now she has a stalemate and probably can't do better. We ought to make certain that she at least gets a stalemate. For this she will probably need from us substantial further destroyers and air-reinforcements to England. We should not precipitate anything in the Orient that would hamper our ability to do this – so long as probability continues. If England remains stable, Japan will be cautious in the Orient. Hence our assistance to England in the Atlantic is also protection to her and us in the Orient. However, I concur in your courses of action. We must be ready on both sides and probably strong enough to care for both.

Stinnett writes that while "no specific record has been found by the author indicating whether [Anderson] or Roosevelt actually ever saw it [. ] a series of secret presidential routing logs plus collateral intelligence information in the Navy files offer conclusive evidence that they did see it". [8] His evidence of "secret presidential routing logs" is not provided. [9] Stinnett goes on to write, "throughout 1941, it seems, provoking Japan into an overt act of war was the principal policy that guided FDR's actions against Japan" and "Roosevelt's cabinet members, most notably Secretary of War Henry L. Stimson, are on record favoring the policy, according to Stimson's diary". [8] Further evidence that suggests Roosevelt had seen the memos was his support of "pop-up" cruises, [2] an elaboration upon Actions D and E of the eight recommended actions detailed in the memo: "I just want them to keep popping up here and there and keep the Japs guessing. I don't mind losing one or two cruisers, but do not take a chance on losing five or six." [8]

Admiral Husband E. Kimmel, on the other hand, opposed the "pop-up" cruises, saying they were "most ill-advised and will result in war if we make this move", [8] but "the decision [on the 'pop-up' cruise matter] may go against me". [10] In fact, at the time, Kimmel was not aware of Washington's eight-action policy. [11]

Admiral James O. Richardson also opposed the plan and "quoted the President as saying: 'Sooner or later the Japanese would commit an overt act against the United States and the nation would be willing to enter the war'." [12]

Also, Admiral Nimitz turned down the command of the Pacific Fleet [12] so that he would not become the scapegoat [ citation needed ] if the Japanese attacked the United States by surprise. In a History Channel interview, Admiral Chester Nimitz Jr. described his father's political maneuver:

He said, 'It is my guess that the Japanese are going to attack us in a surprise attack. There will be a revulsion in the country against all those in command at sea, and they will be replaced by people in positions of prominence ashore, and I want to be ashore, and not at sea, when that happens.' [13]

The characterization of the McCollum memorandum as a recipe for war was not accepted by U. S. Army military historian [14] Conrad Crane, who wrote:

A close reading shows that its recommendations were supposed to deter and contain Japan, while better preparing the United States for a future conflict in the Pacific. There is an offhand remark that an overt Japanese act of war would make it easier to garner public support for actions against Japan, but the document's intent was not to ensure that event happened. [15]

Today in History: Born on June 21

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Planning Pearl Harbor

encapsulates the enormous difference between the Nihon Teikoku Kaigun--the Imperial Japanese Navy--which opened the Pacific War in December 1941, and the small Japanese Maritime Self-Defense Force (JMSDF), which today plays a modest role in cooperating with the U.S. Navy to preserve the security of Japan's home waters.

The old navy constituted a mighty fighting force. At the opening of the Pacific War, it comprised 10 battleships 10 aircraft carriers 38 cruisers, heavy and light 112 destroyers 65 submarines and numerous auxiliary warships of lesser size. At the time, Japanese naval aviation was world class: Its fighter aircraft and medium bombers were among the world's finest, and among the major navies, its air crews were unquestionably the best trained and most experienced. To have observed the Japanese battle line in column on maneuvers in the northern Pacific during the interwar years, to have viewed the vast bulk of the superbattleship Yamato anchored in Truk lagoon, or to have watched the clouds of fighters and attack aircraft lift off the decks of six carriers in the early morning of December 7 must have been among the great spectacles in modern naval history. Never again will Japanese naval power be so visually impressive.

The Imperial Japanese Navy was emblematic of the rise of Japan as a world power. Yet the overriding aspect of the Japanese navy is its ultimate defeat. Indeed, it was not just beaten by the U.S. Navy it was annihilated. To Americans of an older generation, particularly those who fought against Japan's navy, that defeat has been a cause of considerable satisfaction and pride. To older Japanese, particularly those who served in their navy, it is a source of humiliation and regret. For those scholars on both sides of the Pacific who study the Japanese navy, its ultimate defeat is the ineluctable fact in assessing its capabilities, its combat performance, even its victories. The Imperial Japanese Navy set in train the events that would lead to its annihilation, rousing the United States against it with a brilliant tactical success and a strategically disastrous provocation, the attack on Pearl Harbor. It is an irony that the attack was planned by a man who opposed war with the United States, Admiral Yamamoto Isoroku.*

Earliest Conceptual Origins

The conceptual origins of the preemptive aerial strike against the U.S. Pacific Fleet at Pearl Harbor--when and how it was conceived, how it evolved, and along what lines--are not entirely clear to this day. Admiral Yamamoto, commander of the Combined Fleet, is usually identified as the creator of the concept. Hard evidence suggests, however, that before Yamamoto proposed it early in 1941, the idea had been propounded in varying degrees of detail and similarity to the actual attack.

To have watched the clouds of fighters and attack aircraft lift off the decks of six carriers in the early morning of December 7 must have been among the great spectacles in modern naval history.

At least some of those conceptual precedents may have stimulated Admiral Yamamoto's thinking on the subject. At furthest remove are the civilian writings of the 1920s and 1930s--Japanese, American, and British--on the possible course of a Japan-U.S. war in the Pacific. Some of this speculation was informed, some of it merely sensational. But references to a Japanese attack on Hawaii were so generalized and so diverse in assumed conditions and outcomes that their existence demonstrates only that such vague ideas were floating about in public during these decades.

A Japanese officer like Yamamoto was probably more influenced by studies undertaken by fellow professionals in his own navy than by any other source. And, indeed, several other Japanese naval officers had tested, written about, or spoken about the concept by the time it was taken up by Yamamoto. It is logical to assume that, over time, Yamamoto became conversant with their assessments. But if Yamamoto did not originate the concept, it took someone in the Japanese naval high command of his position, stature, and heretical outlook to make the argument at the highest levels and then push it through to activation.

It was the results of the fleet's naval air training in 1939–1940, however, that provided the immediate stimulus for the formation of Yamamoto's Pearl Harbor plan. Because of Yamamoto's efforts, the fleet had begun to emphasize air power in its annual training and maneuvers, which brought together the various air units of the fleet. Of special interest was a simulated raid by carrier-based torpedo planes against warships in the harbor at anchor. Although there was much disagreement on the results of that particular exercise, Yamamoto was evidently persuaded that such an attack, if coupled with surprise, would be a success. By the end of the maneuvers in the spring of 1940, Yamamoto had realized that the range and firepower of Japanese naval aviation could make possible a telling first blow against the American enemy, even in his home waters.

About this time, too, his ideas may have been furthered by a memorandum from his senior staff officer, Captain Kuroshima Kameto, on the possible opening moves of a Japan-U.S. war. Although making no reference to Hawaii, Kuroshima proposed a long-range surprise attack by carriers against the enemy's battle force.

In reflecting on the evolution of the preemptive strike concept, it is important to understand its rationale in Yamamoto's thinking. Abundant evidence suggests that Yamamoto was fundamentally opposed to a war with the United States and Britain. Yet, as commander of the Combined Fleet, he had a keen sense of responsibility that he must have at hand the most effective means for victory if war came. In Yamamoto's view, the navy's strategic orthodoxy--the wait-and-react strategy--was a recipe for ultimate defeat. Unable to bring the U.S. Navy to battle on Japanese terms, the Combined Fleet would simply be worn down in a long war in which the United States would eventually bring its vastly superior industrial might--and thus overwhelmingly superior naval strength--to bear.

But what concrete alternatives were there? Air power suggested a solution, but the Japanese navy had too little of it. This being the case, how best to use air power most effectively? The advance of the U.S. Pacific Fleet from San Diego to Pearl Harbor in May 1940 probably furthered the preemptive strike idea in Yamamoto's thinking. As late as the end of October of that year, however, he still apparently considered the idea too dangerous. Perhaps the remarkable success of the British torpedo bombing attack on Italian ships at anchor at Taranto convinced him that the potential gain was worth the risk. In any event, sometime in November, judging from his communications to a few trusted colleagues, he concluded that a preemptive aerial attack on the Pacific Fleet at its Pearl Harbor base offered the Japanese navy its best chance in a war against great odds.

On January 7, 1941, Yamamoto committed his ideas to paper in his blandly titled memorandum Gumbi ni kansuru shiken (Views on military preparations) to the navy minister, Oikawa Koshiro. Its first major point was that the navy needed to greatly expand its air forces. Second, he noted that although fleet training had been based on the wait-and-react strategy leading up to the classic gun battle in past war games and maneuvers, the navy had never succeeded in winning such an encounter. Usually, the exercises were called off before umpires deemed the navy's strength exhausted. Moreover, Yamamoto argued, the power of aircraft and submarines made it unlikely that a decisive gun battle would ever take place. Hence, the navy needed to give its commanders better training in small-unit tactics for the numerous smaller engagements that would most likely occur.

Most of all, in Yamamoto's view, it was essential to change the navy's basic strategy. As a quantitatively inferior naval power, Japan's best hope lay in a qualitatively superior strategy: a violent and crippling first blow at America's main battle force in the first few hours of the war. Time, distance, and geography dictated that this could best be accomplished by an air attack by several carrier divisions on the U.S. Pacific Fleet at Pearl Harbor.

Yamamoto did not downplay the enormous risks involved in the operation. Although he had complete confidence in the technical and combat skills of the navy's carrier forces, the enormous distance involved--far greater than any operation in the navy's history--and the great risks of discovery made executing the operation a dangerous proposition. The plans for the surprise attack on Russian naval forces at Port Arthur in 1904 had been far less complicated, far less taxing, and far less hazardous, and yet the objectives had been met only incompletely. It was why, originally, Yamamoto wished to lead the Pearl Harbor strike force himself.

The General Staff Resists

Since the beginning of 1941, the general staff had been proceeding with its planning for a war with the United States on the basis of that year's annual operational plan. This in turn was predicated on the wait-and-react strategy, governed largely by the priorities of the "southern operations" to secure Southeast Asia and its resources for Japan. In heated arguments during the summer of 1941 between the general staff and Yamamoto's Combined Fleet staff over the wisdom and propriety of the Hawaii operation, the chief of the staff's Operations Section, Captain Tomioka Sadatoshi, provided an extensive list of objections to the Hawaii plan. In sum, he argued that the Japanese navy could not afford to wager its carefully built-up naval air strength in such a desperately risky venture, particularly in view of the fact that it would be needed in other major operations. More than anything else, Tomioka feared that diverting surface and air strength to the Hawaii attack would critically undermine the southern operations and, hence, the major objectives of the coming war. Even if the navy were willing to undertake such an enormous gamble, in Tomioka's view, the Pearl Harbor strike was not truly necessary. Of course, there was the danger that the U.S. Pacific Fleet might try to hit the southern operations in the flank, but Tomioka argued that the enemy would far more likely launch an attack on the Marshall Islands. That would be all to the good since the navy had great confidence that it could intercept the enemy there and launch a smashing counterattack.

As a quantitatively inferior naval power, Japan's best hope lay in a qualitatively superior strategy: a violent and crippling first blow.

The bitter controversy between the general staff and the Combined Fleet staff was not resolved during the summer of 1941, even as training and preparations for the Pearl Harbor operation continued. Nor was it resolved during the September map exercises at the staff college or in October aboard the Nagato those discussions and exercises relating to the Hawaii operation were held separately and were accessible only to those few naval officers who would be involved in carrying it out. Of all the points of contention, the sharpest concerned the number of aircraft carriers to be used in the attack. Yamamoto had originally proposed four the September map exercises simulated an attack with three, which the umpires judged to have achieved only marginal results. But those on the general staff working out the details for the invasion of Southeast Asia insisted on reserving some carriers for the southern operations since the navy's land-based air power, specifically its fighters, did not have the range to reach the necessary targets and return.

The Plan Falls into Place

Then, in early October, the navy general staff was brought around to Yamamoto's idea. There were several reasons for this volte-face, some operational, some bureaucratic. To begin with, the compromise between the army and navy on nearly simultaneous attacks on the Philippines and Malaya eased navy planning considerably. The availability of the splendid new carriers Shokaku and Zuikaku in late September permitted two other carriers to be released for the southern operations and thus eliminated one of the general staff's key objections to the Yamamoto plan. Finally, Yamamoto had carefully and quietly passed the word to the high command that rejection of the Pearl Harbor plan would result in his resignation. Keenly aware of Yamamoto's popularity and prestige within both the navy and the government and faced with the prospect of disharmony, the general staff gave in.

Later in the month, however, a new storm of controversy broke when Yamamoto insisted that the Hawaii operation employ all Japan's fleet carriers then in commission. He based his views on the map exercises aboard the Nagato, which used six carriers the results with six carriers were judged far more impressive than with only four carriers. Opposition from the general staff might have derailed the Pearl Harbor strike once and for all, had it not been for the success of tests in the Eleventh Air Fleet, which demonstrated that engine adjustments to the Zero fighters based on Taiwan made them operational for flights to and from the Philippines. Now that the task forces involved in the southern operations would be supplied with adequate air cover, the last barrier to the Yamamoto plan came down.

On November 5 the Combined Fleet's Operations Order No. 1 secretly briefed senior officers on the impending war plans, including the cryptic statement, "To the east, the American fleet will be destroyed." Vice Admiral Nagumo, commander of the First Air Fleet and overall commander of the Pearl Harbor strike force, received his final instructions six days later. On November 22 the strike force began to assemble in its cold and lonely rendezvous, Hitokappu Bay in the Kurile Islands: six carriers, two battleships, two heavy cruisers, one light cruiser, nine destroyers, three submarines, and eight tankers and supply ships. Four days later, in heavy fog, the advance elements of the strike force, including the carriers, departed Hitokappu and sailed into history.

Excerpted and adapted from Kaigun: Strategy, Tactics, and Technology in the Imperial Japanese Navy, 1887–1941, published by the Naval Institute Press. To order, call 800-233-8764.
Available from the Hoover Press is the Hoover Essay A Historian Looks at the Pacific War, by Mark Peattie. To order this essay, call 800-935-2882.

How the Japanese Did It

Pearl Harbor. Of all the aspects of the attack on that 7 December 1941 Sunday morning-including its treachery, swiftness, daring, and skillful execution-none seems more compelling than the assault's total surprise. This element is even more striking, knowing that just prior to the attack, a U.S. Army radar site at Opana Point, on Oahu, tracked incoming aircraft, and the Navy discovered a foreign submarine at the entrance to Pearl Harbor. Add to this mixture that American code-breakers were reading Japanese diplomatic messages of all types, and it seems simply incredible that Japan could pull off a thorough surprise attack.

Yet it did precisely that. How Japan could do so has intrigued Americans ever since. Vast literature, written mostly from an American perspective, has poured out in the last six decades pursuing answers to the same questions: How did the Japanese arrive in secret, and why were the Americans caught so off guard? Not unexpectedly, these writings mostly dwell on American errors and shortcomings and usually treat Japanese planning and preparations for the strike in an abbreviated, sometimes dismissive manner. Even a standard history such as Gordon Prange's At Dawn We Slept concludes with 11 pages recounting American failures, while giving Japanese efforts three paragraphs, one of which attributes a major place to "unadulterated luck." 1 Proponents of the Pearl Harbor conspiratorial thesis reduce the Japanese to mere puppets, acting unconsciously to the whims of President Franklin D. Roosevelt (and, according to a few, British Prime Minister Winston Churchill). 2

While the air assault that morning was, in the words of Pacific Fleet commander Admiral Husband E. Kimmel, a "beautifully planned and executed military maneuver," it was the Japanese preparations that allowed the Pearl Harbor Task Force, the Kido Butai, to approach Hawaii undetected. 3 Without the detailed planning and nearly flawless execution of the preliminaries, the attack would have never succeeded.

Comprehending Japan's prewar change in naval strategy and how the Japanese combined four major parts of the assault plan-denial and deception (D&D), radio intelligence (RI), cryptology, and operations security-is critical to understanding how the Japanese were able to pull off the attack. These components often complemented each other. One part would lead, reinforce, or extend another, and lessons learned during training and exercises sorted out which techniques worked. Simply put, how the Japanese prepared for the attack is what assured their success that morning, and it is likely the Americans could have done nothing to alter significantly the outcome of the attack.

Switching from Defense to Offense

Strategy is the script nations write for themselves that dictates subsequent policy and plans. Japan's pre-eminent interest after World War I was to expand and preserve economic hegemony in East Asia, principally China. But to fulfill that strategic aim, Japan would face opposition from colonial powers in the region and from the United States, which sought to maintain an economic "Open Door" in China and protect its island possessions. In the years prior to Pearl Harbor, Japanese-American relations were marked by confrontations over Japanese expansion into China, the seizure of Manchuria, and a buildup of naval forces and facilities in the Pacific.

Japan's naval strategy closely followed its national aims. It envisioned a two-part mission: support operations to expand to the south into Southeast Asia and the Netherlands East Indies, while protecting the Home Islands from an expected attack by the U.S. Pacific Fleet, which might threaten Japan directly or its commercial supply routes.

The effective spearheads for the Western Pacific foreign policies of both nations were their respective navies: the Pacific Fleet and the Imperial Japanese Navy (IJN). Both countries expected and trained for eventual conflict. For the Japanese, though, the naval strategy it adopted for most of the two decades prior to 1941 was essentially defensive in nature. While elements of the IJN would be engaged elsewhere to the south, the majority of the battle line-its battleships, supplemented with carriers-would remain in the home waters around the Japanese archipelago and await the expected riposte by the reinforced Pacific Fleet. Once the American ships deployed, the Japanese fleet would sortie out and seek a "decisive battle" somewhere in the mid-Pacific region. 4

As ship technology advanced and Japanese carriers acquired more punch from more capable aircraft, the location of the climactic clash moved eastward until, by the late 1930s, the Japanese Naval General Staff (NGS) planned for it to occur near the Mariana Islands, some 1,400 miles southeast of Japan. Ironically, and with implications for Pearl Harbor, American plans fit neatly together with the Japanese expectations. American naval planners, in War Plan Orange and its various permutations, would send the reinforced Pacific Fleet across the Central Pacific to meet the Japanese Combined Fleet somewhere near the Marshall or Caroline Islands and destroy it before moving on to the Philippines and the eventual investment of the Japanese Home Islands. 5

The Japanese strategic defense scenario remained a fixture in their fleet exercises throughout the years before World War II. American intelligence, mostly through radio intelligence and reports by naval attach?

s, was aware of this plan. As early as 1927, American radio monitors and traffic analysts had plotted the IJN annual grand maneuvers and determined that the Japanese strategic posture was largely defensive. 6 This intelligence estimate, which continued into 1941, convinced the U.S. Navy's leadership that Japan's main battle force would remain in home waters and await the U.S. Pacific Fleet's move west. American naval war planning, epitomized in WPAC-46 under Admiral Kimmel, counted on this inaction and called for an advance across the Central Pacific once hostilities began. 7

In January 1941, however, Admiral Isoroku Yamamoto proposed the idea of a sneak attack on Pearl Harbor. In essence, he overturned more than two decades of Japanese naval strategic thinking. The Japanese NGS opposed this idea for nearly nine months before yielding to Yamamoto. Planning, training, and war games in September 1941 revealed technical and operational shortcomings that needed to be fixed if his plan was to work. Significantly, U.S. naval intelligence did not detect the shift in thinking. American radio intelligence continued to analyze Japanese naval activity in 1941 within the context of the old defensive strategy. U.S. analysts assumed the carriers and most of the battle line would remain in Japanese home waters. All Yamamoto needed was some way to convince the Americans to continue to think that way.

Covering Up the Strategic Change

The key to the success of the Japanese attack on Pearl Harbor-specifically, what enabled the Pearl Harbor Striking Force to reach its launch point undetected (and totally unsuspected) by the Americans-was Tokyo's radio denial-and-deception actions. Significantly, these activities simply were not just a "bag of tricks" meant to bemuse U.S. naval radio intelligence. Rather, they constituted a function of the change in Japanese strategy and were meant to convince the Americans that there had been no change from defensive to offensive intentions.

Two observations about Japanese D&D further explain its success. First, the impetus for the IJN's elaborate radio ruse was its awareness of the ability of enemy radio intelligence to identify and locate Japanese carriers. Earlier, in March and June 1941, when carriers had been dispatched south to support Tokyo's policy toward occupied French Indochina, Japanese radio intelligence discovered that the British monitoring site in Hong Kong had identified and tracked the large ships. (It is not known if the Japanese realized that American naval radio intelligence had done so as well.) Alerted to the vulnerability of its communications to foreign RI, the Japanese naval command was compelled to devise a counterplan. 8

Second, the radio D&D program began in mid-November 1941 on the heels of a weeklong communications drill-a series of scheduled radio contacts between selected ships and stations. 9 The deception was intended to appear to American radio monitors in the Philippines and Hawaii as a continuation of the same communications exercise. The drill had begun as the ships of the Kido Butai moved to a rendezvous point in the Inland Sea of Japan. The deception phase kicked in as the ships of the task force "buttoned up" on their way to the Kuriles on 17 November.

Beginning in mid-November, the American stations in Hawaii and the Philippines intercepted about a dozen transmissions-no messages, just calls and radio "chatter"-seemingly from the IJN carriers. This paucity of monitored emissions worked to Japan's advantage since it reinforced an American perception that Tokyo's carriers were in home waters and largely inactive, which was reported in Communications Intelligence Unit summaries to Admiral Kimmel as "nothing on the carriers" or "no information." Kimmel would report to various hearings that these periods of silence or inactivity were nothing new at least eight times in the previous six months it was uncertain where the ships were because of few or no transmissions. 10

As the carriers' apparent transmissions were picked up by the U.S. Navy monitoring station at Corregidor, the Philippines, direction-finding (DF) gear was used to plot lines of bearing on the their call signs. 11 The resulting lines crossed over the Japanese naval bases of Sasebo, Kure, or Yokosuka, which suggested the carriers were at these bases. For American naval intelligence analysts in Washington, Hawaii, and the Philippines, the congruence of the lines verified the conclusion that the carriers were still in home waters as expected, refitting, training, or preparing for the expected emergence of the Pacific Fleet from Pearl Harbor. 12 More important, these lines of bearing also coincided with results obtained on the carriers' transmissions from August through November 1941, as the IJN operated in the waters around the southern Home Island of Kyushu. 13

Whatever projections U.S. naval authorities had about the activities of the IJN in late 1941, they included no sense of an immediate threat to Pearl Harbor by Japanese carriers. Their own radio intelligence confirmed this.

Monitoring American Radio Traffic

The role of Japanese radio intelligence, primarily by the IJN, but also the small part played by Japan's Post, Telegraph, and Telephone (PT&T) Ministry, has remained largely unknown to Americans. Most narratives mention a small team on board the Kido Butai's flagship, the carrier Akagi, which listened to Hawaiian commercial stations for any alert. But that is a mere fraction of the story.

Briefly, radio intelligence is information that can be gleaned from communications excluding cryptanalysis. RI is derived from the "externals" of messages and the transmission of such traffic, such as message priority, call signs, and radio direction finding. In a useful analogy, radio intelligence is like studying the envelope and delivery method of a letter. We can learn who sent it, the date, relative size, and the delivery system. But any conclusion based on RI is largely inferential and can be misleading without corroborative intelligence.

For years before the Japanese Navy began to grapple with Yamamoto's idea for a surprise attack on Pearl Harbor, the IJN's radio intelligence section had monitored U.S. Pacific Fleet exercises and activities. While the Japanese intercepted and studied the communications of other fleets in the Pacific, such as the Royal Navy and Soviet Pacific Squadron, the Pacific Fleet was its priority target. Like most major navies, Japan had established an RI capability early in the 1920s. Radio intelligence was handled in the "Special Section" of the Communications Department of the Navy General Staff, which used listening posts on various Japanese-held islands. Tokyo also dispatched merchant ships with special monitoring teams on board to track annual U.S. fleet exercises. 14

In late May 1940, President Roosevelt ordered the Pacific Fleet to remain in Pearl Harbor after the completion of Fleet Problem XXI. (The fleet had been based in San Diego, California, with Pearl Harbor serving as an advanced deployment base.) Roosevelt hoped it would act as some sort of deterrent. 15 An unexpected result of the move, however, was that the Pacific Fleet's communications were now within range of the Japanese RI station on Kwajalein. Listening in on Pearl Harbor, this unit, the First Detachment of the Sixth Communications Unit, was able to gather much more intelligence than before the transfer. Additional information came from Japan's PT&T Ministry, which monitored commercial telegrams and radio telephone calls by Pacific Fleet Sailors to their families on the mainland. Sailing schedules, supply-train arrivals, unit manning, and ship locations were available in open communications. 16 The Japanese also copied Pacific Fleet headquarters communications with Navy outposts on Midway, Guam, Samoa, and Johnston Island.

Into the summer of 1941, as plans for the attack on Pearl Harbor advanced, the IJN beefed up its radio-intelligence coverage of the American military presence in Hawaii. Two more stations, on Saipan and near Tokyo, now covered the communications of the Pacific Fleet and the U.S. Army Air Corps in Hawaii. A new RI command structure in Tokyo organized the effort with a greater emphasis on ship identification and direction finding. Daily reports from Kwajalein, which included listings of U.S. Navy call signs for its ships and shore stations, were passed to Tokyo. Call signs for ships such as the USS Arizona (BB-39), Enterprise (CV-6), and Astoria (CA-34) were noted. 17 The Kwajalein DF station tracked the routes of American aircraft flying among the U.S. Pacific bases, but more important, it tracked reconnaissance flights around the Hawaiian Islands. The results revealed that the flights were almost exclusively to the west and south of the island chain. The north, the direction from which the Kido Butai would approach, remained uncovered.

Radio intelligence supplemented reports from Japanese agent Takeo Yoshikawa, who operated out of the consulate in Honolulu. His information was the primary intelligence source for the IJN on Pearl Harbor, but his tenure was precarious. At any time he could be compromised and shut down. Also, his reports were limited. He provided little information on U.S. air activity around Hawaii, his intelligence could take up to two days to reach the Kido Butai, and he had no way of monitoring radio communications. When the attack came, his role would end. Japanese RI, however, could compensate for all the shortcomings.

The U.S. Pacific command did not miss the spike in Japanese DF activity. A daily Traffic Intelligence Summary presented to Admiral Kimmel noted that since October Japanese DF nets were extremely active. The 28 November edition carried an assessment by Commander Edward Layton, Kimmel's fleet intelligence officer, that the Japanese DF was "getting results." 18 Because U.S. naval intelligence could not read the DF messages encrypted in a special cipher, Layton could not have known that they contained information on the critical holes in the American aerial reconnaissance around Hawaii.

One further aspect of Japanese RI against Hawaii occurred in late 1940 as the U.S. Army Signal Corps was testing a new speech-scrambler system for radio telephone calls between Honolulu and San Francisco. Designed by AT&T, this A-3 device was already in use between Washington and U.S. embassies in Europe. When the scrambler was turned on for the test, an operator in Japan broke in and asked if something was wrong with the channel, because Tokyo could not understand the voice transmission between the two American terminals. This indicated that the Japanese PT&T Ministry was monitoring calls between Honolulu and the United States. 19

As the Japanese strike force approached the Hawaiian Islands, it was receiving current radio intelligence via a Tokyo naval broadcast (which it did not need to acknowledge by radio), from monitoring and DF units at three land sites, as well as from an RI team on board the Akagi, which listened not just to commercial broadcasts from Honolulu but naval and air communications as well. Additionally, numerous Japanese Sixth Fleet submarines dispatched earlier to scout the area and attack U.S. ships carried small radio-intercept teams, whose mission was to provide intelligence to the submarines. 20

The Japanese RI effort would keep the Kido Butai informed of any changes to the status of U.S. forces in Hawaii and warn the task force if its presence was known.

Breaking the Japanese Codes

Japanese cryptology, like its radio-intelligence program, began in earnest after World War I. The IJN opted for codebooks and charts. It further encrypted messages by using auxiliary systems such as transposition ciphers, which scrambled the code groups according to a key. Thanks to a combination of good cryptanalysis and the purloining of copies of these early codes, American code-breakers from the Navy's OP-20-G broke and exploited the encrypted messages for about 15 years.

In mid-1939, the IJN brought in a new general purpose operational code, designated AN by the Americans. Its codebook contained more than 35,000 five-digit code groups and a digital cipher to encrypt them. American naval code-breakers had made limited progress on this system when the Japanese replaced it in December 1940 with a new code, designated AN-1, with more than 50,000 code groups.

The mistaken claim that the AN-1 code was being "read" or exploited at the time of Pearl Harbor is based on out-of-context quotes and numerous technical misunderstandings of the U.S. code-breaking process. A review of the monthly progress statements of the U.S. Navy's code-breaking section, OP-20-GYP-1, shows minimal recovery of the code-only about 8 percent of the 50,000 code groups had been recovered. The U.S. Navy could not glean intelligence from messages encrypted with AN-1 until early 1942, and even then, the results were fragmentary at best. 21 No intelligence about Pearl Harbor could come from this source.

The Americans, however, could exploit encrypted Japanese diplomatic messages to a great degree, though not quite as much as imagined by later historians. From late 1939 to mid-1940, Japan introduced new diplomatic ciphers to protect their communications. These included the iconic Purple cipher device and several manual systems, including the J-19 enciphered code. Within 1.5 years, these systems had largely succumbed to American Army and Navy code-breaking elements. Still, the rates for exploitation of these messages were not that high. From 1 November to 7 December 1941, 59 percent of all Purple messages between Tokyo and Washington and 16 percent of J-19 were translated. 22

Japan's own code-breaking effort was another story. While Japanese naval cryptanalysts could make no headway into the primary U.S. naval systems, Tokyo could read American diplomatic systems, including old codes such as the Brown and Grey series. Unknown to the Americans, however, Tokyo also could read the high-level system M-138 strip cipher. Considered secure by the Americans, the system had been compromised in 1940, and the Japanese Foreign Ministry was able to read many significant American diplomatic dispatches prior to hostilities. 23 It is still unclear what advantage the Japanese gained from this ability.

Keeping the Secret

Operations Security (OPSEC) consists of all measures taken to ensure that intelligence about operations, activities, etc., is denied to an enemy. Although defensive in nature, certain OPSEC techniques, such as quarantine, can be proactive.

For the Japanese, securing the secret of the Pearl Harbor operation meant instituting security measures to restrict access to knowledge of the attack to only those who had "the need to know" as well as to keep anyone-foreign or domestic-away from Kido Butai training areas, facilities, or personnel.

From the beginning of the planning for the Hawaii operation in early January 1941 until the summer of that year, the IJN kept information about the plan limited to small groups of officers within the operations and command staffs of the Combined Fleet, the Naval General Staff, and the First Air Fleet. By August and September, as preparations intensified, more people within the IJN learned of the plan. Army and civilian leaders were alerted to the plan late in 1941. It is possible that the senior Army leadership learned of the plan by August and cabinet officers in early November, but details were only forthcoming in late November. 24 The Japanese diplomats in Washington and Honolulu were not informed of the attack, which was the best way to ensure they sincerely relayed Tokyo's insincere negotiating points.

Within the IJN, the 700 printed copies of Yamamoto's Combined Fleet Top Secret Operations Order No. 1 of 5 November 1941 to the IJN did not carry the annex for the Hawaiian operations. The majority of senior officers of the Kido Butai were not officially notified of the plan until 17 November, when Yamamoto held his last conference with the task force commanders. The rest of the crews were not told of the attack until the ships reached the anchorage at Tankan Bay in the Kuriles on 23 November. There, all mail and communications between the sailors and Japan were curtailed. 25

Interestingly, Japanese OPSEC around the plan extended to their enciphered diplomatic and naval messages. Tokyo's diplomatic traffic included references to activity in Southeast Asia and a probable starting date for the campaign, 8 December (Tokyo time) as "X-day," but these only tipped off Japanese movements toward Southeast Asia. Yoshikawa's reports from Honolulu were no different than those from other sites such as Manila and the Panama Canal-detailed intelligence but no mention of an attack. Encrypted operational, weather, and training messages meant for the Kido Butai never openly mentioned Pearl Harbor the plan and target could only be inferred from the postwar decrypts.

Japanese restrictions against prying attaches and diplomats proved effective. Areas around Kyushu as well as the southern island's navy yard and training areas had been closed off to foreign observation. By 17 November, the American ambassador to Tokyo, Joseph Grew, informed Washington that security was so tight in Japan that the embassy could no longer be counted on to provide an effective war warning. 26 Japanese newspaper stories about the navy had been censored. Foreign ships approaching training areas near Kyushu had been stopped. Potential adversaries' ships were escorted out of the area, while one, a Filipino freighter, was boarded, its radio sealed and seized, and the ship sailed to Naha, Okinawa. 27

This OPSEC blanket over the operations was not perfect. In at least one case in September, aircraft from the Hiryu spotted a small foreign combatant near one of the Kido Butai training areas. Still, overall, knowledge of the attack was held closely within Japan and away from foreigners.

And on the Morning of the Attack . . .

On 7 December, naval and military commands in Hawaii did not suspect an attack would happen, though in previous years, studies and exercises had imagined such an event. In Washington, the same frame of mind existed among the political, naval, and military leadership. Washington and Honolulu were aware of the Japanese threat to attack areas in Southeast Asia. Reports had come in of Japanese troopships and escorts moving south toward Malaya and of aerial reconnaissance over the Philippines, developments indicating plans in that region. But Pearl Harbor? A surprise attack was not part of the calculations in Honolulu or Washington.

This unpreparedness had nothing to do with an imaginary conspiracy high within the U.S. government. The reason was that the commands in Washington and Honolulu acted according to the intelligence they had received, almost exclusively, from U.S. radio intelligence and diplomatic code-breaking. The intelligence told them the Japanese were moving south and hostilities were likely to begin soon, but Pearl Harbor was not in danger. The best available intelligence on the only real threat to the Pacific Fleet, the Japanese carriers, indicated they were in home waters. This is what Admiral Kimmel reported to the Roberts Commission soon after the attack. So certain was he that there was no threat, he had held back patrol planes to have them ready for the expected order to execute an offensive plan, WPAC-46. 28

In Washington just a few hours before the attack, the Office of Naval Intelligence handed its estimate of Japanese naval forces to the secretaries of State, War, and the Navy. It placed all of the IJN's fleet carriers at home. The Japanese radio deception had spread like a virus, infecting the intelligence assessments in Hawaii and Washington. 29 Japan had successfully hid its polar change in strategy and now had the Combined Fleet, including its attack carriers, ready to hurl its aircraft at Hawaii. Japanese radio intelligence listened in on an unsuspecting Pacific command, while Tokyo's cryptology and OPSEC kept foreign intelligence at arm's length. In a telling detail, that morning Army Chief of Staff General George C. Marshall decided not to phone Honolulu with news the Japanese would that day present "what amounts to an ultimatum." Likely recalling the incident of the Japanese listening in on the A-3 scrambler tests, he instead chose to send the information in a telegram. 30

All of this is not to say the Japanese did not make mistakes or tempt chance. They did. The part of the attack plan that called for midget submarines to infiltrate Pearl Harbor nearly ruined the surprise. The carrier task force sailed east "blind." Submarines meant to scout ahead were pulled back because of high seas, and the Kido Butai's air chief, Commander Genda Minoru, decided against air reconnaissance because the planes could get lost, ask for a navigational beacon, and possibly compromise the force's location. 31

Still, the Americans never pierced the shroud the Japanese Navy draped over the Pearl Harbor attack. Due to the sparse information, intelligence officers like Edwin Layton may have occasionally been uncertain of the carriers' location, but at no time did he or others have any indication of the approaching Kido Butai. The Japanese completely fooled U.S. intelligence.

The implication of that is a far more sobering conclusion than any imagined conspiracy, for it revealed that a knowledgeable and technically adept opponent could effectively negate apparent advantages held by the American intelligence community. So effective was the Japanese denial-and-deception campaign that, when asked during a Pearl Harbor investigation when he finally again heard from the carriers, the chief of the Communications Intelligence Unit in Hawaii, Commander Joseph Rochefort, could only reply, "The 7th of December." 32

1. Gordon W. Prange, At Dawn We Slept: The Untold Story of Pearl Harbor (New York: McGraw-Hill, 1981), pp. 725–737.

2. Principally, Robert B. Stinnett, Day of Deceit: The Truth about FDR and Pearl Harbor (New York: Free Press, 1999) and James Rusbridger and Eric Nave, Betrayed at Pearl Harbor: How Churchill Lured Roosevelt into World War II (New York: Summit Books, 1991).

3. U.S. Congress, Hearings before the Joint Committee on the Investigation of the Pearl Harbor Attack, 79th Congress . (Washington, D.C.: U.S. Government Printing Office, 1946) (cited hereinafter as PHH), Part 22: p. 388.

5. American naval planning was sometimes more aggressive in its timetable, but its objectives remained constant. See Edward S. Miller, War Plan Orange: The U.S. Strategy to Defeat Japan, 1897–1945 (Annapolis: Naval Institute Press, 1991), pp. 286-315.

6. For example, see Various Reports on Japanese Grand Fleet Maneuvers (July-September 1935), SRH-225. (Fort Meade, MD: National Security Agency, 1983).

7. PHH, Part 22: p. 328 Miller, pp. 282–285, 294–5, 317–8.

8. Ishiguro Interview No. 8, 1 May 1948. University of MD, Prange Collection, Box 19, Folder: "Ishiguro Aboard Soryu."

9. Japanese Naval Translation (SRN) 116602. National Archives and Records Administration, College Park, MD (cited hereinafter as NARA), RG 457, Entry 9014.

10. PHH Part 24: pp. 1,385-6 Robert J. Hanyok, "Catching the Fox Unaware. Japanese Radio Denial and Deception and the Attack on Pearl Harbor," Naval War College Review (Vol. 61, No. 4, Autumn 2008) pp. 99-124.

11. The USN monitoring station in the Philippines, along with the analytic section, often referred to as CAST, had moved from Cavite to Corregidor in October 1940.

13. "Translations of Intercepted Enemy Radio Traffic and Miscellaneous World War II Documentation," NARA, RG 38, Entry 344, Box 1356, "Akagai."

14. A good example of Japanese merchant ship as a radio monitoring platform, the tanker Ondo Maru , which monitored the Pacific Fleet Fleet Problem of 1937. See "JN Tanker Activity against USN Maneuvers (1937)," NARA, RG 38, Inactive Stations, Box 18, Folder 3222/12.

16. Yokoi Tishiyuji, Rear Admiral, The Black Chamber of the Imperial Japanese Navy (July 1953), pp.15–16.

17. "Japanese Analysis of U.S. Navy Message Headings," November 1941, RG 457, Entry 9032, Box 151, Folder 646.

18. SRMN-012, "Combat Intelligence Unit, 14th Naval District Traffic Intelligence Summaries with Comments by CINCPAC, War Plans, Fleet Intelligence Sections, 16 July 1941-30 June 1942" (Fort George G. Meade, MD: NSA/CSS, 6 September 1985), pp. 205-230.

20. PHH, Part 13: p. 414 "Translations of Intercepted Enemy Radio Traffic and Miscellaneous World War II Documents," NARA, RG 38, Entry 344, Box 221.

21. NARA, RG 38, Entry 1040, Box 116, Folder 5750/202, "History of GYP-1 RG 38, CNSG Library, Box 22, Folder 3222/82 for first translation from JN-25B (then AN-1) completed on 8 January 1942.

22. PHH, Part 37: pp. 1081-3 "Worksheets for Japanese Diplomatic Traffic, 1941," RG 38, Entry 1030, Box 165, Folder 5830/62, "Pearl Harbor Investigations."

23. "Survey of Cryptographic Security at the Department of State," RG 457, Entry 9032, Box 1384, Folder 4400 Cryptanalytic Section of the Japanese Foreign Office," DF-169, CSGAS-14, July 1949 NSA Memorandum, FM D33, 3 January 1968, "State Department Messages," NSA MDR 52717. The existing set of Japanese decrypts can be found in the Diplomatic records Office, Tokyo, "U.S.-Japan Relations, Miscellaneous Diplomatic Correspondence-Special Information File." (A-1-3-1, 1-3-2).

24. Robert Butow, Tojo and the Coming of the War (Palo Alto: Stanford University Press, 1961), p. 375 Donald M. Goldstein and Katherine V. Dillon, The Pearl Harbor Papers (Dulles, VA: Brassey's, 2000), p. 142.

25. NARA, RG 457, Entry 9014, SRN 115678 and 117814.

26. PHH, Part 14: pp.1058-60, "Tokyo to Washington," 17 November 1941, Serial 711.94/2447.

27. NARA, RG 457, Entry 9014, SRN 116763 and SRN 117693.

29. "Locations of U.S. Naval Force in the Atlantic, Pacific and Far East Also Foreign Naval Forces in the Pacific and Far East: as of 7 December 1941," PHH, Part 20, pp. 4121-31.

30. PHH. Part 3: pp. 1211-1214 Michael Gannon, Pearl Harbor Betrayed (New York: John Macrae, 2001), pp. 233–4.

The Navy’s most successful World War II sub also killed an enemy train

Posted On April 29, 2020 15:41:54

The Gato-class, diesel-powered US Navy submarine USS Barb is known for a lot of things. In 12 war patrols, she sank the third most tonnage in World War II, had eight battle stars, and fired the first submarine-based ballistic missiles on Japan. It earned her crew a Presidential Unit Citation, among numerous other awards and decorations.

But one of its proudest moments was also its most daring. Crewmembers aboard the Barb were also the first American combatants to set foot on Japanese home soil — in order to “sink” an enemy train.

They did all of this without losing a single man.

On Jul. 23, 1945, eight members of Barb‘s crew landed on mainland Japan under intense cloud cover and a dark moon. Their mission was to rig a Japanese train track to explode when a train crossed a switch between two railroad ties. Immediately, their best-laid plans went right out the window, forcing the crew to improvise.

The USS Barb off the coast of Pearl Harbor, 1945.

The mission of the USS Barb was to cut the Japanese fleet’s supply lines by sinking enemy ships out of the island of Karafuto in the Sea of Okhotsk. This was the ship’s 12th war patrol, and the fifth for her skipper, then-Commander Eugene Fluckey. They could see as Japanese shipments moved from trains on the island to the ships. Once the ships were at sea, they were easy pickings for crews like the Barb’s.

But why, Fluckey thought, wait for the ships to get to sea? Why not just take them out before the trains ever reach the port? That’s exactly what Fluckey and his crew set out to do.

They couldn’t just place charges on the tracks, it would be too dangerous for the shore party once the Japanese were alerted. Instead, the U.S. Naval Institute tells us how Engineman 3rd Class Billy Hatfield devised a switch trigger for an explosive that, when set between the rails, would go off as the train passed over it.

That was the goal as the crew manned their boats and made it ashore that night, but they accidentally landed in the backyard of a Japanese civilian. So, they ended up having to struggle through thick bulrushes, cross a freeway, and even fall down drainage ditches on their way to the railway. Once there, a crewman climbed to the top of a water tower — only to discover it was a manned lookout post. Luckily, the guard was asleep and their work continued.

They dug holes for the 55-pound bomb as quickly and as quietly as possible, even having to stop as a freight train rumbled by. But they did it, put the pressure switch into place, and booked it back to the ship as fast as possible. At 1:47 am, a 16-car train hit their planted explosive and was shot into the sky. Five minutes after that, the crew was back aboard the Barb.

The Battle Flag of USS Barb, the train is located bottom middle.

Barb’s battle flag could now boast one enemy train “sunk” in combat, along with six Navy Crosses, 23 Silver Stars, 23 Bronze Stars, and a Medal of Honor earned by members of its crew.

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Pearl Harbor Day: How did Adolf Hitler react to the attack?

Exactly 70 years ago Japan hit Pearl Harbor with one of the most stunning surprise attacks in history. At the time Japan was already one of the Axis powers, linked with Italy and Germany. Given that, how did the Führer, Adolf Hitler, react?

Hitler did not know of the Pearl Harbor plan beforehand. When informed in his headquarters on the evening of Dec. 7 of the strike and the damage suffered by US forces, he was “delighted,” according to British historian Ian Kershaw.

“We can’t lose the war at all. We now have an ally which has never been conquered in 3,000 years,” a jubilant Hitler said, as recounted in Mr. Kershaw’s authoritative biography of the German leader.

IN PICTURES: Pearl Harbor remembered

This comment was typical of Hitler in that it was both grandiose and a touch self-delusional. In fact, Hitler viewed the Japanese through the lens of his own racial prejudice. In “Mein Kampf” he patronizingly wrote that Japanese scientific and technical progress would cease without “Aryan” influence. His top lieutenants recalled that he accepted Japanese gains in the Far East with some resignation, and occasionally warned that eventually Germany would find itself in a showdown with what he called the “yellow race.”

But for Hitler, the Japanese triumph at Pearl Harbor came at an opportune time. Operation Barbarossa, the German invasion of the Soviet Union, had stalled. On Dec. 6, the Soviets had launched a counterattack that would eventually save Moscow and doom Hitler’s dream of an empire in the East.

Thus Hitler seized on Pearl Harbor as a light in the general gloom. His assumption was that the Japanese would now tie down the United States in the Pacific and weaken Britain by threatening its Asian possessions, according to Kershaw.

Germany and Japan had already agreed on a strengthening of their existing Tripartite Pact, which would bind each to declare war on a power attacking the other. This provision had not been formally signed, however, meaning that Hitler by treaty was required only to aid Japan, not enter the war against the United States.

But for Hitler this was a foregone conclusion – he wanted to ensure that Japan would stay in the war, and perhaps invade Russia from the east. He also felt that war with the US was inevitable, and he wanted to take the initiative. On Dec. 8, he ordered German U-boats to sink US ships on sight.

In a lengthy speech to the Reichstag on Dec. 11, Hitler recounted recent military events, excoriated President Roosevelt, and declared war on the United States. Given that US public opinion was far harsher about Japan than Germany, this was a mistake, writes British journalist and historian Max Hastings in his history of World War II, “Inferno.”

“Four days after Pearl Harbor, [Hitler] made the folly of the strike comprehensive by declaring war on the United States, relieving Roosevelt from a serious uncertainty about whether Congress would agree to fight Germany,” writes Mr. Hastings.

The Japanese, for their part, had begun the war with the US in the belief that Nazi Germany was an unstoppable force that would soon conquer the Soviet Union and end the war in Europe. So the Axis powers lurched forward, each blind to the particular strategic situation they now faced.

The Path to Pearl Harbor

On December 7, 1941, Japan staged a surprise attack on Pearl Harbor, decimating the US Pacific Fleet. When Germany and Italy declared war on the United States days later, America found itself in a global war.

Top Image: Propaganda poster developed by the Office of War Information following the attack on Pearl Harbor. (Image: Library of Congress, LC-USZC4-1663.)

On December 7, 1941, Japan staged a surprise attack on Pearl Harbor, decimating the US Pacific Fleet. When Germany and Italy declared war on the United States days later, America found itself in a global war.

The Roots of the Conflict

While Japan’s deadly assault on Pearl Harbor stunned Americans, its roots stretched back more than four decades. As Japan industrialized during the late 19th century, it sought to imitate Western countries such as the United States, which had established colonies in Asia and the Pacific to secure natural resources and markets for their goods. Japan’s process of imperial expansion, however, put it on a collision course with the United States, particularly in relation to China.

To a certain extent, the conflict between the United States and Japan stemmed from their competing interests in Chinese markets and Asian natural resources. While the United States and Japan jockeyed peaceably for influence in eastern Asia for many years, the situation changed in 1931. That year Japan took its first step toward building a Japanese empire in eastern Asia by invading Manchuria, a fertile, resource-rich province in northern China. Japan installed a puppet government in Manchuria, renaming it Manchukuo. But the United States refused to recognize the new regime or any other forced upon China under the Stimson Doctrine, named after Secretary of State and future Secretary of War Henry L. Stimson.

The ineffectual Stimson Doctrine guided US policy in Asia for the next decade. On the one hand, the doctrine took a principled stand in support of Chinese sovereignty and against an increasingly militaristic Japanese regime. On the other hand, however, it failed to bolster that stand with either material consequences for Japan or meaningful support for China. In fact, US companies continued to supply Japan with the steel and petroleum it needed for its fight against China long after the conflict between the countries escalated into a full-scale war in 1937. But a powerful isolationist movement in the United States countered that the nation had no business at all in the international conflicts developing around the world. Even the Japanese military’s murder of between 100,000 and 200,000 helpless Chinese military prisoners and civilians and the rape of tens of thousands of Chinese women during the 1937 Rape of Nanking failed to immediately shift US policy.

The strong isolationist movement also influenced the initial US approach to the war in Europe, where by the end of 1940 Nazi Germany controlled most of France, Central Europe, Scandinavia, and North Africa, and severely threatened Great Britain. Prioritizing the war in Europe over Japan’s invasion of China, the United States allowed the sale of military supplies to Great Britain beginning in 1939. But neutrality laws and isolationist sentiment severely limited the extent of that aid prior to 1941.

“Each [nation] stepped through a series of escalating moves that provoked but failed to restrain the other, all the while lifting the level of confrontation to ever-riskier heights.”

The war in Europe had another significant impact on the war in the Pacific because Germany’s military successes unsettled the other European nations’ Asian colonies. As Japan seized the opportunity to become the dominant imperial power in Asia, United States-Japan relations soured. As historian David M. Kennedy, PhD, explained, “Each [nation] stepped through a series of escalating moves that provoked but failed to restrain the other, all the while lifting the level of confrontation to ever-riskier heights.”

The Impending Crisis

President Franklin Delano Roosevelt made one of those escalating moves in July 1940 when he cut off shipments of scrap iron, steel, and aviation fuel to Japan even as he allowed American oil to continue flowing to the empire. Japan responded by entering resource-rich French Indochina, with permission from the government of Nazi-occupied France, and by cementing its alliance with Germany and Italy as a member of the Axis. In July 1941, Japan then moved into southern Indochina in preparation for an attack against both British Malaya, a source for rice, rubber, and tin, and the oil-rich Dutch East Indies. This prompted Roosevelt to freeze all Japanese assets in the United States on July 26, 1941, which effectively cut off Japan’s access to US oil.

That move pushed Japan to secretly ready its “Southern Operation,” a massive military attack that would target Great Britain’s large naval facility in Singapore and American installations in the Philippines and at Pearl Harbor, thus clearing a path for the conquest of the Dutch East Indies. While diplomatic talks continued between the United States and Japan, neither side budged. Japan refused to cede any of its newly acquired territory, and the United States insisted that Japan immediately withdraw its troops from China and Indochina.

On November 26, 1941, as US officials presented the Japanese with a 10-point statement reiterating their long-standing position, the Japanese Imperial Navy ordered an armada that included 414 planes aboard six aircraft carriers to set to sea. Following a plan devised by Admiral Yamamoto Isoroku, who had earlier studied at Harvard and served as Japan’s naval attaché in Washington, DC, the flotilla aimed to destroy the US Pacific Fleet base at Pearl Harbor.

To catch the Americans by surprise, the ships maintained strict radio silence throughout their 3,500- mile trek from Hitokappu Bay to a predetermined launch sector 230 miles north of the Hawaiian island of Oahu. At 6:00 a.m. on Sunday, December 7, a first wave of Japanese planes lifted off from the carriers, followed by a second wave an hour later. Led by Captain Mitsuo Fuchida, the pilots spotted land and assumed their attack positions around 7:30 a.m. Twenty-three minutes later, with his bomber perched above the unsuspecting American ships moored in pairs along Pearl Harbor’s “Battleship Row,” Fuchida broke radio silence to shout, “Tora! Tora! Tora!” (Tiger! Tiger! Tiger!)—the coded message informing the Japanese fleet that they had caught the Americans by surprise.

The USS Arizona in flames following the Japanese attack on Pearl Harbor, December 7, 1941. Image: Library of Congress: LC-USZ62-104778.

For nearly two hours, Japanese firepower rained down upon American ships and servicemen. While the attack inflicted significant destruction, the fact that Japan failed to destroy American repair shops and fuel-oil tanks mitigated the damage. Even more significantly, no American aircraft carriers were at Pearl Harbor that day. The Japanese, however, immediately followed their Pearl Harbor assault with attacks against US and British bases in the Philippines, Guam, Midway Island, Wake Island, Malaya, and Hong Kong. Within days, the Japanese were masters of the Pacific.

In Washington, a decrypted message had alerted officials that an attack was imminent moments before Fuchida’s planes took to the skies. But a communications delay prevented a warning from reaching Pearl Harbor in time. The Americans missed another opportunity when an officer discounted a report from an Oahu-based radar operator that a large number of planes were headed their way.

Examine the facts and timeline of the Attack on Pearl Harbor on December 7, 1941

President Franklin D. Roosevelt speaking to Congress on December 8, 1941 said “Yesterday, December 7, 1941—a date which will live in infamy—the United States of America was suddenly and deliberately attacked by naval and air forces of the Empire of Japan.”

TIMELINE of the attack on Pearl Harbor on December 7, 1941

  • At 6:10 AM, Minesweeper USS Condor sights a periscope
  • At 6:10 AM, the first wave of planes took off from Japanese aircraft carriers, approximately 200 miles north of Oahu.
  • At 6:45 AM, the first shots fired by the USS Ward at a Japanese submarine. These were the first shots fired by the United States in World War II.
  • At 6:53 AM, USS Ward radios Navy headquarters but the decoding process delays the message.
  • At 7:02 AM, A radar station on Oahu spots unidentified aircraft heading toward Hawaii.
  • At 7:20 AM, Army lieutenant disregards this radar report because he believes it is a flight of U.S. B-17 bombers coming from California.
  • At 7:40 AM, the first wave of Japanese aircraft reaches Oahu.
  • At 7:49 AM, the Japanese aerial commander orders the attack on Pearl Harbor.
  • At 7:55 AM, the Coordinated attack on Pearl Harbor begins.
  • At 8:10 AM, the USS Arizona explodes.
  • At 8:17 AM, the Destroyer USS Helm fires at and sinks Japanese submarine at entrance to harbor.
  • At 8:54 AM, the second wave of attack begins.
  • At 9:30 AM, the USS Shaw explodes in dry dock.
  • At 10:00 AM, Japanese planes head back to carriers and ultimately back to Japan.


  • Japan’s aerial attacking force at Pearl Harbor involved 353 planes, 29 of those planes were lost in the attack. Japan’s fleet consisting of some 67 ships was located approximately 200 miles north of Oahu.
  • Only one ship that participated in the attack on Pearl Harbor survived through the end of World War II.
  • Locator map of Oahu as part of the Hawaii islands
  • Map of Oahu showing the directions of the first and second waves of attack by the Japanese towards Pearl Harbor.
  • Map of Pearl Harbor with Ford Island in the middle showing where all of the United States ships were docked and the directions of the flight paths of Japan’s attack squadrons

Map also shows which ships were damaged:

  • U.S. Ships that were a total loss: Arizona, Oklahoma, Utah
  • U.S. Ships damaged and repaired: Curtiss, Raleigh, Nevada, Vestal, West Virginia, Tennessee, Maryland, California, Oglala, Helena, Shaw, Cassin, Downes, Pennsylvania, Honolulu
  • Battleships USS Arizona and USS Oklahoma along with former battleship, now target ship USS Utah were a total loss and never returned to service. USS West Virginia was the only ship attacked at Pearl Harbor present during Japan’s formal surrender on September 2, 1945.
  • A total of 2,404 United States military and civilians were killed, 1,177 were killed aboard the USS Arizona and 68 civilians were killed. A total of 64 Japanese military were killed with one taken prisoner
  • 15 United States Navy personnel received the Medal of Honor and 51 received the Navy Cross. The Pearl Harbor Commemorative Medal was later given to all military veterans of the attack.

Sources: Naval History and Heritage Command, National WWII Museum

The relationship between Japan and the United States had soured in the years leading up to Pearl Harbor. This began with the Japanese invasion of Manchuria in 1931, an expansion throughout the Chinese mainland that led to the Second Sino-Japanese war between China and Japan in 1937. Japan then joined the Berlin, or Tripartite Pact, forming an alliance with Germany and Italy in 1940.

The war in Europe had opened up strategic opportunities for the Japanese conquest of European colonial holdings, such as French-Indo China, British Malaysia and Singapore, Dutch Indonesia and the Philippines.

Following the invasion of French-Indo China in 1941, the U.S. froze Japanese assets in the United States and declared an embargo on petroleum shipments. U.S. oil accounted for eighty percent of Japan’s oil imports at the time. By late 1941, the United States had severed practically all commercial and financial relations with Japan.

Japanese military strategy was based on the peculiar geography of the Pacific Ocean and on the relative weakness of Allied military presence there. The western half of the Pacific is dotted with many islands, while the eastern half of the ocean is almost devoid of land masses and hence, usable bases except for Hawaii.

The British, French, American, and Dutch military forces in the entire Pacific region west of Hawaii amounted to only about 350,000 troops. Allied air power in the Pacific was weak and consisted mostly of obsolete planes.

The Japanese believed they could quickly launch coordinated attacks from their existing bases on certain Pacific islands and overwhelm the Allied forces, planning to establish a strongly fortified defensive perimeter. They believed that any American and British counter offenses against this perimeter could be repelled, after which those nations would eventually seek a negotiated peace that would allow Japan to keep this newly acquired empire.

On the morning of December 7th, at 6:10 AM, the first wave of Japanese planes launched. At 6:45 AM, the USS Ward spotted and open fired on a Japanese submarine off the coast of Hawaii. At 6:53 AM, the Ward reported sinking the sub, but decoding the message took time. At 7:02 AM, a radar station on Oahu spotted unidentified aircraft heading towards the island. However, radar systems were less than a month old, and the lieutenant who received the warning thought it was a false alarm. By 7:40 AM, the first wave of Japanese aircraft had reached Oahu, having evaded American early warning systems. Shortly thereafter, the Japanese aerial commander ordered the attack.

The Japanese aircraft flew in two waves. The first wave attacked airfields and anti-air defenses on the west side of the island, while the second wave, almost an hour later, concentrated on the eastern side. Both waves met over Pearl Harbor.

In the harbor, anchored ships made perfect targets for the Japanese bombers. Most of the damage to the battleships occurred in the first thirty minutes of the assault. The Arizona was completely destroyed and the Oklahoma capsized. The California, Nevada and West Virginia sank in shallow water. However, the Pacific fleet’s three aircraft carriers were at sea during the attack, and the Japanese failed to destroy the important oil storage facilities on the island. All but two of the battleships were returned to service during the war, and overall U.S. naval strategy in the Pacific shifted to rely on aircraft carriers over battleships as a result.

Japan’s fleet of 67 ships was located about 200 miles north of Oahu. They launched dive bombers, torpedo bombers and fighter planes. There were 353 Japanese aircraft involved in the attack, 29 of which were shot down. Only one Japanese ship that participated survived to the end of the war.

In total, 2,404 U.S. military personnel and civilians were killed. 1,177 of those casualties were aboard one ship–the USS Arizona, where an armor-piercing bomb struck and ignited over a million pounds of gunpowder within the ship. Sixty-eight civilians were also killed.

After the battle, fifteen individuals were awarded the Medal of Honor and fifty-one were awarded a Navy Cross for their actions in battle. The following day, President Franklin Delano Roosevelt addressed the United States, and the U.S. Congress declared war against Japan. Three days later, Germany and Italy declared war on the United States. And the previously reluctant nation entered the Second World War.

The attack on Pearl Harbor is credited with uniting the U.S. population behind the war effort. It is estimated that between 35 and 65 million people died during the Second World War, including civilians killed as a result of war, those that died from disease, and those killed during the Holocaust.

The Second World War resulted in the expansion of the Soviet Union’s power throughout Eastern Europe, the spread of communism to China, the advent of nuclear weapons, and the decisive shift of world power away from the states of Western Europe and toward the United States and Soviet Union.

Watch the video: The Attack on Pearl Harbor: The Japanese Plan and the Planning Behind It