Were the early strategic decisions made by World War II Japanese Admiral Isoroku Yamamoto, commander of the Imperial Japanese Navy's Combined Fleet, the best choices available? Did his unconventional moves, particularly Pearl Harbor and Midway advance or harm Japanese war aims?  (One might add a third and in retrospect rather puzzling excursion, the IJN raid into the Indian Ocean in early 1942.)  Is there an alternate history resulting in more favorable prospects for Japan -- other than not starting a war against an industrial giant like America in the first place?

Herein we examine the choices Yamamoto made and compare them to alternatives.  One can never know what lies at the end of a path not taken, so in suggesting alternatives we engage in flights of unprovable conjecture. But, it is interesting, if not useful nonetheless to reexamine Yamamoto's critical 1942 choices, decisions that helped fix the course of the war, aided by the 20-20 vision of hindsight.

Certainly Yamamoto was an innovative commander, among the first to recognize and use massed naval air power as a strike weapon. The manifestation of this innovation was the concentration of IJN carrier air power into the First Air Fleet or Mobile Striking Force, in Japanese the kido butai. As well, he was a leader of men, inspiring intense loyalty among those under his command. Among his peers in Japan’s military hierarchy, his prestige was such that the mere threat of resignation caused his superiors to accede to his demands. Finally, he was a gambler, both for amusement and as a military strategist, willing to paint strategy with bold strokes for the possibility of even greater gains.

But, did his choices advance Japan's war aims as he hoped? Were his bold plans brilliant strategic thrusts or did they contain fatal flaws?  Objectively, based on outcomes and consequences a case can be made that he made sweeping choices that rather than advancing Japanese military goals instead risked all and hastened Japan’s eventual defeat.

To be sure, Yamamoto did not want war with America.  Having studied in the US extensively, he observed first hand the industrial might of America as well as the potential of a population that greatly outnumbered Japan's.  But, when war became inevitable Yamamoto advocated for and obtained concurrence for two signature operations that are at the heart of this discussion, the surprise attack on Pearl Harbor and the attempted invasion of Midway. The former was intended to forestall US Navy interference with Japan’s move south to take over the resources of British Malaya and the oil rich islands of the Dutch East Indies. The latter was a tactic he thought would draw forth USN carriers for destruction. Pearl Harbor at first appeared to be a success, but was it?  Midway certainly backfired because with the loss of four of Japan’s six fast fleet carriers the IJN no longer had the capital assets to attempt bold carrier-led strategic attacks.

 

Pearl Harbor

After the US embargoed scrap steel and oil in an attempt to restrain Japanese agression in China, Japan began planning a move south in order to secure oil and other minerals for its war machine as well as homeland internal needs. The Pearl Harbor strike was intended to prevent US interference with this move by crippling the US fleet. In strategic terms, Pearl Harbor could be considered a failure since the USN's only two carriers in the Pacific at the time, Enterprise and Lexington, were not in port on that fateful morning, rendering the attack of little lasting strategic value.  (Saratoga was on the West Coast at the time of the strike, returning to Pearl Harbor soon thereafter, and Yorktown and Hornet were later dispatched from the Atlantic, the latter in time for the April Doolittle Raid.)

But, suppose that the Pearl Harbor attack had never taken place. After all, the IJN General Staff strongly opposed the plan -- relenting only after Yamamoto threatened to resign along with his entire Combined Fleet staff.  What might have happened in the early months of 1942 if Yamamoto had given up the scheme?  Would it have changed the early course of the war?  Would the American public have been less inflamed by subsequent Japanese actions, for instance against the Philippines, absent the sneak attack?

While the US fleet would have been free to intervene as Japan moved south, it would have had to do so in the far western Pacific, Japan's home turf, thousands of miles from logistical support. This was exactly the situation Japan’s navy planners had long hoped for -- a strong submarine war of attrition as the US fleet crossed empty ocean, followed by a climactic battle in Japan’s back yard, the outcome of which, Japan hoped, would be final destruction of the US fleet.

Yet, the US Navy had no plan to pursue this path.  The Navy's long standing blueprint for war with Japan, War Plan Orange and it’s 1941 incarnation, Rainbow 5, proposed using American industrial might to build up overwhelming military superiority before island hopping across the Pacific.

In pursuit of this, a total of 32 Essex class fast fleet carriers were authorized during the war, of which 24 were actually built, not all of which were delivered before war's end. Compared to this, Japan managed to add only the Taiho to the original six fast fleet carriers that struck Pearl Harbor. Against such overwhelming force it is difficult to imagine the eventual end of the war being any different than it was, although it likely would have taken longer and involved more US casualties.

The Philippines constituted another flash point for war in the Pacific.  Absent Pearl Harbor, if Japan had left the Philippines alone the Roosevelt administration would then have had no casus belli to rally Congress and civilian support for a war. Yet much of the US defensive strategy throughout 1941 revolved around strengthening the Philippines as a bulwark against Japanese agression.  Could Japan have afforded to leave the Philippines in American hands in light of this build up?  Japan's decision makers simply could not afford to leave a US strong presence athwart their supply lines to the oil rich territories to the south. Hence, the Philippines were invaded and overwhelmed, which would undoubtedly have forced the US into war independent of Pearl Harbor.

Nor did the Philippines matter in the end. President Roosevelt had privately assured Churchill that if Japan attacked British interests in the Far East, as they ultimately did, America would take up arms as Britian’s ally. All this was done without Congressional approval, a nicety mooted by the Pearl Harbor attack.

This alternate beginning to the war lends credence to the thesis that the Pearl Harbor strike was not necessary and may well have been counterproductive.  The Pacific Fleet could not have interfered with Japan's move south even if left alone. Further, the plan was problematic from conception to execution.  There was never any certainty that American's carriers, the capital ships that posed the greatest threat to Japan, would be moored at Pearl on December 7. Perhaps worst of all, the failure to destroy Pearl’s submarine base, fuel storage tank farms and repair facilities -- far more important strategic targets than a bunch of slow and aging battleships, most of which were salvaged, repaired and turned against Japan as shore bombardment platforms.  All Pearl Harbor really accomplished was to rouse the American "sleeping giant" that Yamamoto feared so much.

 

Midway

Having failed to sink the two USN carriers in the Pacific at the time, Enterprise and Lexington, Yamamoto devised a highly complex operation involving virtually the entire Japanese fleet, the objective of which was to simultaneously invade Midway and the Aleutians, with intent of drawing USN carriers forth to defend the Midway atoll where they might be engaged and destroyed by superior Japanese carrier forces.

History has amply recorded the Battle of Midway – US code breaking revealed the Japanese plan in sufficient detail to allow Yorktown, Enterprise and Hornet to ambush the Japanese carrier force, sinking all four present – Akagi, Kaga, Soryu and Hiryu. Here however, we are not interested in the battle, but rather in other choices Yamamoto might have made.

Midway was preceeded by a Japanese attempt to take Port Moresby, an Australian outpost on the southern coast of New Guinea.  This was the opening salvo of a plan to extend Japan's defensive perimeter, in the process cutting off and isolating Australia.  Kido butai carriers accompanying the Port Moresby invasion force, headed by only Shokaku and Zuikaku, collided with Yorktown and Lexington in the Coral Sea, the first ever naval battle where the combatant ships never saw each other. While Lexington was lost, a tactical defeat, the Japanese invasion of Port Moresby was recalled, a strategic victory for the USN.

Where were the remaining four carriers of kido butai ?  They were in Japan undergoing maintenance following a pointless excursion into the Indian Ocean, a side show that accomplished little of strategic value.  They were thus unavailable for the Port Moresby invasion.  Worse, Shokaku suffered serious damage in the Battle of Coral Sea, and Zuikaku's air group was decimated by USN F4F Wildcats and shipboard AA fire, thus removing them from the Midway operation.

If Midway had never been attempted and instead the invasion of Port Moresby had been fully supported by the entire kido butai, Port Moresby would likely have fallen.  That would have opened the door for investing Samoa, Fiji and New Caledonia, breaking the allied link to Australia.  This, the US could not have allowed to go unopposed.  In fact, according to historian Craig Symonds' book Midway, some in the Navy General Staff bitterly opposed the Midway plan and wanted Yamamoto to do just that, a direction that was supported by the Japanese Army.  But, Yamamoto overrode this recommendation by again threatening to resign, instead forcing a decision for Midway and the Central Pacific.  The Doolittle Raid on Japan soon thereafter, by Army B26 Mitchells flying from the deck of Hornet, removed any remaining opposition to Yamamoto's plan.

Given the vital importance of Australia to the allied coalition it is doubtful that the USN could have refused battle if Japan had chosen to attack the South Pacific in full force even with the entire kido butai. With an intact First Air Fleet, and with the US Pacific Fleet’s home base in Hawaii thousands of miles away, the odds would have been strongly in Japan’s favor.  Had the US Navy chosen to oppose the invasion under these conditions both Yorktown and Lexington would likely have been lost -- and perhaps others as well.  If so, the US Navy would have been powerless to stop the IJN from running wild in the South Pacific. The grinding attrition of Guadalcanal would never have happened. New Caledonio, Fiji and Samoa, sitting athwart the lifeline to Australia, would all have fallen. Australia would have been isolated and perhaps invaded.

 

Hindsight

If this analysis has merit -- albeit illuminated by hindsight -- Yamamoto would have been better advised to have lured the US carriers out for battle in conjunction with Japanese advances in the South Pacific, a region not only vital to the US interests but also integral to Japanese war goals.

Midway was surely the strategic blunder that initially turned the tide of war against Japan – perhaps made worse by the Indian Ocean raid, a futile exercise that left four of Japan's six fast fleet carriers unavailable for the Port Moresby invasion.  As the war actually played out, the Guadalcanal abattoir forever blunted any further Japanese offensive initiatives. From that point on, as Essex class carriers began to deliver in numbers and as US military might began to pour into the Pacific, the outcome was foreordained.

In Yamamoto’s gambler’s idiom, he pushed four of Japan’s irreplacable kido butai carriers to the center of the table in a winner-take-all bid – and lost everything.

Author's footnote:  I've always been fascinated by the Pacific War. My first recollection of television was watching Victory at Sea on a small grainy black-and-white set.  Inspired by the stirring Richard Rodgers theme music, I followed each episode, mesmerized by the titanic issues involved.  That fascination has carried on to this day.  This article joins two previous explorations of the era, Carrier War 1942 and Midway 2019 Movie Review.