Alan D. Zimm Read online

  This logic holds only if the enemy fights the type of war that you expect, that you want him to fight. If the enemy should operate otherwise, choosing to exploit Japan’s weaknesses rather than confront its strength, then the strategy is exploded, and what was a minor weakness becomes a major handicap.

  The operation to invade Midway reflected Yamamoto’s attempt to defeat the Americans’ will to fight on his terms, with Japan on the offensive. It was to force the Americans into a decisive, morale-busting battle before the flood of new U.S. construction made the force ratios impossible. Instead, the loss of four Japanese fleet carriers made a shambles of Japanese pre-war strategies.

  With the defeat at Midway the Japanese became reactionary, waiting to oppose an American fleet that they expected to concentrate into one large mass, a reversion to Zengen Sakusen. Instead, the war became a struggle of attrition on the fringes, a war of outposts, of cruisers and destroyers and submarines and carrier raids devoid of the massive Jutland-style fleet confrontation upon which the Japanese hopes were centered. Losses were nearly equal, losses which the Americans could replace but the Japanese could not.

  Eventually, after the predicted massive American reinforcements arrived, the U.S. fleets concentrated and offered the prospect of a decisive battle, but with force ratios that the Japanese had little hope of overcoming—especially after the cruisers, destroyers, and aircraft that they had built to execute Interceptive Operations and bleed the American fleet had themselves been bled white in the war of outposts. The Marianas and Leyte became American-instigated Decisive Battles on American terms, after irreparable attrition to the Japanese forces on the periphery of the Co-Prosperity Sphere.

  The lack of forward fortifications concerned the Japanese from the outset. An American move to take the Marshalls early in the war would both threaten the flank of the Japanese drive south as well as create an early breach in Japan’s planned outer defensive arc. The Japanese felt that the Marshalls were not fortified sufficiently to thwart such a move. This was one of the considerations that argued for an initial strike against the American fleet at Pearl Harbor.62

  Given the attitudes that resulted in minimalist facilities, it is not surprising that the Japanese had not considered the possibility that the destruction of port facilities or fuel transportation and storage might immobilize the American Pacific Fleet at Pearl Harbor better than a strike against fleet units. Again there was mirror-imaging in their thinking, expecting the Americans to act as they would have acted. They ignored—or were not aware of—American logistics vulnerabilities, a concern they could have discovered from open-source publications such as Thorpe’s Pure Logistics. Pure Logistics featured an example problem calculating logistics requirements for a “Blue” [US] fleet of 20 dreadnoughts and 20 pre-dreadnoughts crossing a 5,000 nm ocean, with Blue having a mid-ocean base located at just about the same distance from the enemy as Hawaii.

  The Japanese concentrated on destruction of the Pacific Fleet’s warships, a logical approach particularly if they were aware of the CNO’s dictum that a major offensive into the western Pacific would not be conducted until superior US forces were available. However, even with a successful strike at Pearl Harbor, the Japanese could not expect to reduce the American fleet (or, indeed, the Allied fleet, as they were to initiate hostilities with Great Britain and Holland as well the United States) to a combat power less than that of the Japanese fleet.

  The objective of the attack was both material and psychological. The damage inflicted on the enemy was to support the territorial objectives of the war, and to inflict such losses was to establish the psychological state needed to allow the Japanese to win the ultimate victory at peace negotiations.63

  Contradictory Strategies

  Yamamoto’s strategy had a significant consequence that historians have not previously recognized. The attack on Pearl Harbor by its very nature made Japan’s overall concept for winning the war OBE. For Zengen Sakusen to succeed, the American fleet had to thrust west early in the war, before it was reinforced to overwhelming strength. And yet, the Pearl Harbor attack was to immobilize the American fleet for six months. These goals contradict.

  With a six-month delay imposed upon the Americans, there was nothing to prevent them from waiting an additional six months when the arrival of newly constructed ships would give them the means to establish absolute material superiority. The Japanese concocted a narrative where an enraged American people would supposedly demand rapid revenge for the loss of the Philippines, forcing the fleet to move before it was reinforced. At the same time, the Japanese expected the Americans to be so indifferent to the Philippines that they would later barter it away during peace negotiations. From phase to phase the Japanese assumptions were inconsistent and contradictory. Assumptions changed to accommodate the goal of the moment.

  This was a systemic problem within the Japanese high command. The Japanese never were good at formulating political goals and realistically determining the economic and military requirements to achieve them—witness their performance in China, Mongolia, and Korea.

  The Japanese Decisive Battle strategy was questionable from the start. For example, what was to prevent the Americans from just turning around and refusing combat if they took too many losses during the Interceptive Operations? Of even greater concern, when testing their strategy in wargames, was that the Japanese found it impossible to locate the American fleet and execute their attrition attacks. In paper trials, Interceptive Operations and Zengen Sakusen could not be made to work. Perhaps as an expression of psychological avoidance, the basic Japanese plan was never given a trial in a full fleet exercise on the high seas.64

  Japanese assumptions regarding the timing of the American counteroffensive consisted of unanswered questions and ill-founded premises. Why would the Americans move west after six months, with a force close to parity with the Japanese? Why would they not complete the salvage and modernization of ships damaged at Pearl Harbor and await the arrival of new construction reinforcements prior to moving west? Why would they continue an advance if heavy losses were sustained in the approach?

  If Yamamoto’s attack on Pearl Harbor was a success it would work against the only strategy Japan had for victory. It would be a classic case of “win the battle, lose the war”—which was exactly what happened. The choices were never so dramatically illustrated than by a photograph of the battleship Wisconsin tied up alongside the salvaged hulk of the Oklahoma. The Japanese had the dilemma of either meeting Oklahoma at sea early in the war, or striking Pearl Harbor and sinking a few ships like Oklahoma, imposing a delay on the Pacific Fleet, and so later having to face the more modern and powerful Wisconsin and her consorts.

  Yamamoto substituted his vision of a short war coming to a negotiated end—based on the psychological shock of Pearl Harbor and the loss of the Philippines and southern resource areas—for the Naval General Staff’s vision of a short war culminating in Zengen Sakusen. This realization gives better context to Yamamoto’s statement, “If we fail [at Pearl Harbor], we’d better give up the war.” He clearly had no confidence in Zengen Sakusen. Failure had to be defined not in terms of the results of an attack on Pearl Harbor but in terms of achieving what was needed to bring the Americans to the negotiating tables. If the attack on Pearl Harbor succeeded but did not result in negotiations, the losses caused by a successful attack would force the Americans into a long-war strategy, the very war in which Japan had no hope of victory.

  It has been suggested that the strategies were actually complementary: a Pearl Harbor raid would reduce the effectiveness of the Pacific Fleet at the outset of the war, something like an early phase of Interceptive Operations, followed by the Decisive Battle that would convince the Americans that victory was not worth the necessary sacrifices. But Yamamoto did not believe that the Americans would behave in a manner to allow a Jutland-style battle at the outset, and there was no reason to believe that losses at Pearl Harbor would stir Americans into committing the fleet with in
ferior force ratios. Yamamoto had not thought ahead to consider a situation where the losses at Pearl Harbor did not bring the Americans to the negotiating table. The cobbled-together nature of the staff work and negotiations with the Imperial Army preceding the Midway Campaign was the result of Yamamoto’s lack of foresight, as he tried to improvise his way out of the strategic situation he had imposed through the success of the Pearl Harbor attack. At least in Yamamoto’s mind, there was no complementary connection between Pearl Harbor and Zengen Sakusen.

  The psychological aspect of Yamamoto’s objective (as opposed to material destruction) should not be dismissed. It played a significant role in how the Japanese would go about achieving their material objectives. In particular, the psychological aspect called for the attackers to prioritize the American battleships. Rear Admiral Onishi, Chief of Staff of the Eleventh Air Fleet, said Yamamoto believed that “Most Americans—like most Japanese—still believed battleships to be the mightiest weapons of war. The sinking of one or, better yet, a number of these giant vessels would be considered a most appalling thing, akin to a disaster of nature. Such destruction, Yamamoto reasoned, would paralyze the vaunted Yankee spirit.”65

  Yamamoto was after headlines, front page photographs of destroyed battleships. The target was the American people, a people with a prominent and vocal pacifist contingent who were placing pressure on elected representatives not to involve American troops in foreign wars. Most Americans couldn’t find Luzon on a map. The Philippines were to be given their independence in five years. Why spill American blood to prevent something that was already scheduled to happen?

  Yamamoto believed that if Americans could be induced to despair they would place pressure on their government to end the war, leaving Japan in possession of the southern resource areas. He asserted that “American public opinion has always been very changeable, so the only hope is to make them feel as soon as possible that it’s no use tackling a swarm of lethal stingers…. And the one other thing we can do is to take bold risks, resigned from the start to losing up to half our own forces.”66

  Yamamoto did not understand the Roosevelt Administration. They saw things not as “the Japan problem” and “the German problem,” but the problem of defeating the Axis en toto. There would be no contemplation of a separate peace with Japan. Pearl Harbor eliminated Japan’s greatest potential negotiating tool, its offer to switch sides and join the Allies against Germany as the price of a separate peace. The Japanese assumption that a separate peace was possible was fatally flawed.

  The losses at Pearl Harbor and the Philippines did not induce despair. The Americans were not interested in a negotiated, separate peace. With their pre-war assumptions exploded, Yamamoto’s fallback was Zengen Sakusen, with a twist. He must force a final decisive battle onto the enemy by an attack on Midway, which Yamamoto thought would flush out the American battleline. Yamamoto extemporized his way into a course of action that became the greatest role reversal in history.

  After six months of war he gathered together a massive fleet to steam east. He placed himself on what he had proclaimed to be that world-class “folly,” the battleship Yamato, and led an invasion fleet against the island of Midway. He was opposed by Midway’s concentrated air power and the American carriers, in what the Japanese would call an Interceptive Operation. Yamamoto took the course of action Japan had wanted the Americans to take, and the Americans’ Interceptive Operations did to the Japanese what the Japanese had hoped to do to the Americans.

  Even if victorious in the carrier preliminaries, Yamamoto would not have gotten his Zengen Sakusen, as the Americans did not commit the battleships of Joint Task Force One to defend Midway.

  The Battle of Midway has to stand as the greatest irony in military history.

  CHAPTER TWO

  TARGETS, WEAPONS, AND WEAPON-TARGET PAIRINGS

  Initial Estimates

  Yamamoto initially consulted with his close friend Rear Admiral Onishi Takijiro, Chief of Staff of the Eleventh Air Fleet, asking him to begin a study of the feasibility of an attack on Pearl Harbor. They eventually discussed the concept. Yamamoto concluded from the meeting that the attack would be “so difficult and so dangerous that we must be prepared to risk complete annihilation.”1

  Onishi brought in Commander Genda Minoru, the Air Staff Officer of the First Carrier Division. Genda and Onishi were friends, and had discussed a carrier attack on Pearl Harbor several years previously. Genda was a naval aviator with a reputation for iconoclastic brilliance, but also known as “Madman Genda” at the Naval Staff College because of his radical advocacy of aircraft and his expressed belief that all battleships ought to be scrapped.2 He was an advanced thinker regarding the employment of aircraft at sea. His theories became known in the Japanese fleet as “Gendaism.”

  Genda thought an attack on Pearl Harbor would be “difficult but not impossible.” He worked on a draft concept of operations and preliminary assessment, which he presented to Onishi in February. He believed surprise was necessary. The main objective of the attack should be the enemy carriers, with a high priority given to land-based aircraft. The American’s main base in the Pacific was, in modern terminology, “target rich,” with more worthwhile targets than could be serviced by the aircraft from Japan’s four fleet carriers.3 He recommended a balanced daylight attack employing torpedoes, bombs and fighters. There would be sufficient bombs and torpedoes only for the most important targets. Strike assets would have to be carefully allocated. Genda asserted the principle that light damage inflicted to many targets would be trivial and readily repaired, while heavy damage inflicted on key targets could be debilitating. This called for careful allocation of effort.

  The key targets were generically separated into two categories: First, capital ships, the destruction of which was expected to lead to achieving the primary objectives of the attack; second, targets necessary to keep the Japanese strike aircraft and Japanese warships safe.

  There was a third category, that of base infrastructure and logistics facilities. This would include things like the shipyards, drydocks, the submarine base, supply depots, administrative buildings, barracks, and fuel storage. These were not targeted. The striking aircraft simply could not carry enough bombs to do everything. The Japanese should direct their efforts against the fleet and American air power, not facilities.4

  Onishi took Genda’s draft and, after some modifications, presented to Yamamoto what we would now call a “white paper” of some ten pages. Planning began in earnest, expanding to bring in more and more subject matter experts and staff officers. Genda was eventually assigned to handle all portions of the planning relating to aviation, including studies and training.

  The exact requirements of the objective are important. The American fleet was to be immobilized for six months. Heavy damage inflicted on battleships, particularly torpedo or AP bomb hits, would keep them out of the war for at least six months even if there were fully-operational repair facilities available.

  One torpedo hit can put a ship out of commission for months, even if it is hit while closed up for battle. It is not just the hole in the side of the ship and the smashed equipment, but there is also wiring and insulation and pumps and motors and stuffing tubes and other sundry gear that is damaged by salt water, an insidious, corrosive liquid. Shock can damage systems far away from the torpedo hit: torpedo explosions have put gun directors high on a ship’s superstructure out of commission. Pumps can be shocked out of alignment or bounced off their foundations. A British study conducted in 1943 of torpedo hits on cruisers found that, in the 19 cases examined, the average repair time was 9.5 months.5

  AP bombs also could immobilize a battleship for six months if they penetrated into the engineering spaces. In 1937, during damage effects experiments using the obsolete battleship Hannover, the Germans detonated 28cm (11-inch) and 38cm (15-inch) AP shells in her boiler and engine rooms.

  The 28cm shell caused immediate debilitating damage. Burst steam piping would have forced
the space to be evacuated. However, the damage was not so extensive as to preclude repair during a yard overhaul of less than six months.

  The 38cm shell completely destroyed the equipment in the spaces (boilers or engines), requiring complete new installations. The repair work would have required at least six months, more if spare assemblies were not immediately available.6

  These tests would tend to underestimate the damage effects of a shell. The shells were stationary when detonated, so that all the kinetic energy put into the shell fragments came only from the energy released by the explosive charge. The German 28cm APC shell had a bursting charge of 14.55 pounds generating about 27 megajoules, while the 38cm APC had a bursting charge of 41.4 pounds for 78 megajoules. The kinetic energy of the mass of the shell itself would depend on the residual velocity after it penetrates the armor, which would depend upon terminal velocity, armor thickness and orientation, and a host of other factors. If the shell retained 100 meters/second residual velocity (out of a striking velocity on the order of 700 meters/second), another 2 megajoules or 4.3 megajoules, respectively, or 7%, would be added to the energy total.

  It is not known if the Germans passed on the results of their tests to their Japanese allies before the Pearl Harbor attack. However, the Japanese had performed similar tests against Tosa in June of 1924 and likely reached similar conclusions.

  As will be shown in further pages, even several hundred bombs would not have placed the repair facilities out of commission. But if torpedoes and bomb hits on battleships could do the job, then striking infrastructure targets would have been unnecessary—they were irrelevant in the context of the six month objective. In fact, Japanese planners never even considered them as targets.