Alan D. Zimm

by Attack on Pearl Harbor: Strategy, Combat, Myths, Deceptions

  One significant discovery is the extent to which many historians have been wrong in their opinions of the battle. This has in turn led to much distortion in the historical assessments of the roles, skills, and judgment of the participants. Care must be taken before previous historians’ value judgments are accepted. Even the most prestigious of the contemporary warfighters might be wrong.

  The Questions

  In the introduction a number of questions were posed which now can be addressed.

  Were there flaws in the attack planning?

  Was anything forgotten or neglected in the planning?

  In contrast to popular perceptions, the plan was not the “brilliant” effort that has been portrayed. It was not even state of the art for the period. It neglected to take advance of the full capabilities of the attackers, use appropriate existing doctrines, or use the aircraft types in a cooperative manner.

  The plan was too inflexible to take into account last-minute intelligence. Unnecessary reconnaissance flights by floatplanes in advance of the attack were flown, with the potential to forewarn the Americans of the attack, as did the remarkably poor decision to allow the midget submarines to attempt to penetrate the harbor prior to the strike.

  Command and control was not well considered. The plan provided no means for commanders to control their forces during the attack.

  The means to communicate changes in the plan when airborne was ill-considered. The torpedo attack prioritization scheme was faulty.

  Fighter support to guarantee the arrival of the torpedo bombers to their attack points was nonexistent, and first-wave fighter support was not allocated in accordance with the importance of the bomber groups. The fighters were not employed in any organized manner; rather, they were just turned loose to shoot up whatever they discovered, without providing the bombers with escort or SEAD support. There was no provision to post guards over the American airfields, which could have been done employing the excellent endurance of the A6M Zero.

  The plan to deal with torpedo nets was bizarre (but very Japanese). The concept of operations for the torpedo bombers’ attack was not robust, both in the method of target selection and the potential for mutual interference.

  The differences between the “surprise” and “no surprise” plans were miniscule and ineffectual, and the changes insufficient to deal with the threat if indeed the Americans were waiting with their defenses active.

  The plan for delivering the torpedo attack was too hard to execute. Not only were the attack routes in conflict, but the prioritization scheme for selecting targets asked too much of the combat aircrews. The result was that there were only 13 hits (out of 40 torpedo bombers) that effectively advanced the objectives of the attack; it was something of a miracle that these were enough.

  There were many other flaws of omission and commission. The planning was anything but brilliant, even by the standards of 1941.

  If there is a flaw in this analysis, it is that too many of the defects in the attack have been charged against the planners’ account. The planners were working in most cases within the constraints of doctrine, and many of the poor choices (such as target selection methodology, command and control, and communications methodology) might better be attributed to doctrine. The problem is that doctrine was fluid in this period, and in a tantalizing number of cases the planners threw off the constraints of doctrine to embrace innovative solutions (such as reducing the formation size of the level bombers). This analysis blames the planners for not recognizing the need to overturn doctrine in more cases, perhaps unfairly. The point is that there were significant flaws in the attack plan; attributing them to the planners or to the state of the art in doctrine will make for interesting future debates.

  Was the plan state-of-the-art, or were existing useful attack techniques not used? Why not?

  The plan neglected many tools existing at the time that could have contributed to a greater success. There was no SEAD to support the torpedo bombers’ attack, either by strafing fighters or dive-bombers. Fighters were not assigned as a standing CAP to deal with any American fighters that might get airborne. The Japanese simply did not have a combined-arms mindset—it was not in their worldview to have one type of aircraft provide support to the others.

  What was the balance between risk and reward?

  Were Japanese expectations reasonable, or the products of over-optimism, or even self-delusion?

  Yamamoto was risking his fleet carrier force in totality—the platforms, the aircraft, the aircrews, the core of the navy’s aircraft maintenance men, and the sailors that manned the fleet. This was the cream of the Japanese navy’s warfighting power, at the peak of its effectiveness—thereafter, effectiveness could only be expected to deteriorate, and replacements would be limited.

  In wargames it was shown that he possibly would trade two or three of his six fleet carriers and half his aviators to disable four of the US Navy’s 17 commissioned battleships. The odds that he would be able to achieve surprise ought to have been low. Yamamoto was taking on much risk for little relative reward.

  The risk-reward equation was even more unfavorable considering the combat conditions that Yamamoto was willing to accept. He willed the attack to continue even if the fleet was discovered 24 hours in advance. He willed the attack to continue even if the problem of launching torpedoes in shallow water was not solved, or if the American capital ships were protected by torpedo nets. Under these conditions he was willing to trade half his fleet carriers, aircraft and aircrews for only one battleship (the likely result of the level bombers’ attack) and whatever carriers were in port (destroyed by the dive-bombers). And, he willed the attack to continue even if the carriers were not in port.

  In other words, there were a wide range of combat conditions that Yamamoto was willing to accept that would have yielded massive risk for little potential gain.

  In the end, any operation that relies for its success on “divine guidance” and “the favor of the gods” accepts the possibility that the gods might choose to favor the other side.

  Was the operation executed properly?

  No.

  Fuchida’s fumble with the flares turned the air over Pearl Harbor into a scrambled affair. The torpedo bombers’ planned 90-second attack turned into a 11-minute furball. The second-wave dive-bombers went after inappropriate targets, and even then did not hit them. Only the OCA effort was executed as planned, and was rewarded by unforeseen success.

  Most historians have accepted Prange’s assessment:

  The deeper one probes into the technical methods of the attack, the more one realizes how much depended upon surprise, exquisite timing, teamwork, fortitude, and a whole combination of refined skills. Genda and Fuchida’s strategical [sic] and technical brainwork reveals a close attention to detail as well as flexibility.1

  Prange was a historian, not a professional naval officer. He did not know what to look for when evaluating timing, tactics, and teamwork. He mainly took the word of Fuchida and others that he interviewed, Japanese officers who, in the wake of postwar defeat, were not likely to denigrate their great victory. As a result, that great work, At Dawn We Slept, a work which has conditioned the thinking of three generations of historians, is not accurate in its assessment of the objectives, the wargames, the planning, or the execution of the attack.

  Surprise was achieved. Surprise, and the mistakes made by the defenders’ commanders, forgave a multitude of errors in the planning and execution of the attack. Prange’s “exquisite timing” was not achieved; “teamwork” was little evident; “flexibility” on a command level did not exist. The “refined skills” were not evident in the accuracy of the dive-bombing attack on the fleet or in the target selection or precision delivery of the torpedo attack.

  Japanese torpedoes worked well. It will never be determined how many of the approximately ten torpedoes that ended up in the mud were placed there by pilot error or torpedo malfunction, but enough were properly launched to do the job. The 25
0kg GP bombs were plagued with duds and fuze timing inconsistencies, as well as low order and incomplete detonations. The AP bomb performance was miserable. Aviators risking their lives deserve better.

  Did the attack meet expectations?

  Yes. And no.

  The great paradox of the battle, in spite of all the errors and confusion and poor execution that occurred, is that the Japanese tactical expectations were exceeded. At the same time, they came up short in their strategic expectations.

  They needed to disable four battleships to, in their estimation, keep the US Pacific Fleet out of the Western Pacific in any strength. In their wargames, they calculated that they would disable a sufficient number of battleships to change the odds of a battleline confrontation to that which they felt they could win, albeit with only a small margin of victory. They believed that if that level of damage was inflicted, they could delay the counterattack of the Pacific Fleet until after their Phase One conquests were completed.

  The Americans did not steam to the relief of the Philippines until 1944. However, it is questionable whether this was because of the losses inflicted at Pearl Harbor or because of other constraints. Taking the long view, the United States only lost two Treaty battleships and one demilitarized target ship to the attack, along with the services of 15 other ships for periods ranging from a few weeks to 34 months. The 34-month period is deceptive, as those were battleships that underwent extensive modernization, essentially rebuilt from the main deck up, as well as receiving augmented torpedo defenses, work that dragged because their priority for material and shipyard labor was low.

  The OCA effort totally disrupted American airpower, so that, while the Japanese expected to lose up to half of their carriers, their fleet was not attacked at all, again exceeding their expectations.

  The Japanese failed in their greatest of all expectations—that the shock of having their Pacific Fleet eviscerated would bring the Americans to the negotiating table. This did not happen; this miscalculation was The Great Strategic Error of the Pacific War.

  Did the attack meet its potential?

  No, yes, no, and yes.

  Looking first at the torpedo bombers, at the end of their training the B5N Kate aircrews scored 82.5% delivery accuracy, which, if duplicated in the attack, would have meant 33 hits. As a rule of thumb, combat conditions reduce the expected results of an attack by a third, giving an expected 22 effective hits. The Japanese expected 27 hits, and actually hit with 19 torpedoes, less than their expectation. Poor target identification, poor target selection, and overkill reduced the number of effective hits—those hits that advanced the objective of the attack—to 11, while half of the targets high on the priority list, heavy and light cruisers, were untouched. The torpedo attack did not meet its potential.

  The level bombers put in a good performance under difficult conditions. They were both lucky and unlucky: lucky that one bomb hit at just the right spot to detonate Arizona’s magazine; unlucky in that most of their bombs malfunctioned. The Japanese were ecstatic over the results of an attack by a weapons system that was really only an insurance backup to the primary assault weapon, the torpedo.

  The second-wave dive-bombers allocated to fleet targets performed poorly, probably due to the poor visibility, smoke and cloud cover that prevented them from attacking in the way in which they had trained. These aircraft scored only a few hits.

  The attacks against the airfields went spectacularly well. They destroyed two to three times the number of aircraft as could be expected, and totally thwarted any ability of the Americans to perform reconnaissance and assemble a counterattack.

  What would a perfect attack have looked like?

  With the wisdom of hindsight, based on the state-of-the-art of naval aviation attack in 1941 (and its limitations), it is possible to put together the characteristics of a perfect attack.

  It would have begun with flexible planning and training.

  First, the torpedo bombers would be recognized as the core of the attack. They would be expected to inflict most of the damage on the fleet. High-altitude level bombers would be the secondary weapon of choice against inboard battleships, or in the event the Americans decided to employ torpedo nets. Because of the importance of these missions, the more experienced B5N Kate aircrew from Kaga, Akagi, Hiryu, and Soryu would be assigned to strike the enemy fleet. Using the most experienced aircrews would have simplified their training, as some of the aircrew would be asked to train in both roles.

  The Japanese method of level bombing, where all the aircraft in a formation would release when the lead bombardier dropped, could have facilitated planning flexibility. A core of B5N aircrew, the best level bombers, perhaps 20, could have trained exclusively in the role of lead bombers. Another group would train exclusively as torpedo bombers. But the majority of the pilots would train not only to drop torpedoes but also to fly formation in the level bombing roles. These aircrews could fly to the training areas in formation, then practice torpedo delivery, then fly back again in formation. Based on the last-minute intelligence, these aircrews could be assigned to carry either bombs or torpedoes as the last-minute intelligence dictated.

  Better use would have been made of the second-wave dive-bombers against the fleet targets.

  (Appendix D includes a fictionalized account of how a perfect attack against the Pacific Fleet might have been executed.)

  Might the flaws in planning and execution portend things to come?

  The Japanese planning problems would persist throughout the war. There continued to be a lack of cooperation between the combat arms, adding to the catastrophic lack of cooperation between the Army and the Navy. The greatest failures were in a lack of flexibility, and a lack of consideration for contingencies. Japanese plans were made assuming that events would unfold in accordance with their schedule and concept of operations, with little consideration in advance of what to do if other results intruded. There was generally little consideration of alternative scenarios, and little consideration for logistics. But, as has been shown repeatedly, no plan survives contact with the enemy. Yet the Japanese rarely abandoned a plan when the underlying premises upon which it was founded were discovered to be wrong. If the plan exploded, control was mostly lost, as was seen in the Pearl Harbor attack.

  All this suggests a systemic problem with Japanese staffs. Japanese culture may have had a large hand in the problem, including the uncomfortable union of the individualistic samurai tradition, and the extreme consequences of errors or failures in a culture that values consensus and accord. However, these thoughts are nescient, and this question would be a valuable field for future research.

  What could have happened if the Japanese attack had not benefited from the fortuitous blunders of the American high command?

  The calculations indicate that the American command decision blunders before the attack had a huge impact on the results of the action. In the best-case scenario where the Navy and Army were at the level of alert of the previous weeks, and the Air Information Center activated, the Japanese strike would have encountered massive resistance. Perhaps half the Japanese aircraft would have been shot down, a result calculated in the Japanese wargames, the US Naval War College Maneuver Rules, and through historical data analysis, and is not far off the loss rates experienced in the first four carrier vs. carrier actions. An American counterattack with the available land-based bombers might have succeeded in sinking or damaging one or more of the Japanese carriers. Losses to the Pacific Fleet battleships would have been much more limited.

  Coming out of this action would have been a much different concept of naval warfare, one more balanced between employment of battleships and carriers than what was experienced in the war. A battleline action could very well have been seen earlier than the historic battleship confrontations at Guadalcanal and Surigao Strait.

  In spite of these differences, there would likely have been little difference in the course of the Japanese Phase One program of conquest. The American cou
ntermoves were dictated more by logistics than availability of forces—historically, the Americans had plenty of battleships in the Atlantic that could have been transferred to the Pacific, but were not, as what governed Allied action was the availability of fuel and food, and the transportation needed to get these commodities to the western Pacific. The Japanese would have had to rebuild their carrier air wings earlier than what were historically required, meaning that the skill and lethality of the Japanese carriers would have been reduced from the skill levels encountered in the Coral Sea and at Midway. American domination of carrier exchanges would have come earlier than the Battle of the Philippine Sea. Whenever the Americans created the required logistics base, the course of the war, until Japan’s defeat, would have been accelerated.

  Probably the most significant impact of the attack was on the professional worldview of key American naval officers. In the aftermath of the attack, the perception must have been communicated that the battleship force was a weak reed. Yes, Oklahoma and West Virginia were sunk, but no battleship of the period was expected to withstand so many torpedo hits in so short an interval. It was Nevada, sunk after only one torpedo hit and a few bombs, and California, sunk by two torpedoes, and Arizona, blasted into flinders by AP bombs, that stunned the naval establishment. Battleships were expected to take this kind of punishment and survive.

  The American battleships’ design philosophy purposely sacrificed high speed in favor of survivability. Were the designs wrong? Was the concept wrong? If Arizona succumbed to a few AP bombs made out of battleship shells, would not other battleships succumb to a few plunging armor-piercing 16-inch gun rounds? Would American battleships replicate the performance of the British battlecruisers at Jutland, where ship after ship disappeared in awesome magazine detonations, causing Admiral Beatty to lament that “something is wrong with our bloody ships”? Is this, perhaps, the reason why the investigation into the Arizona’s detonation concluded that her loss was attributable to open hatches, rather than admitting that their battleships were vulnerable to armor piercing bombs and exploding magazines?