NAVAL WAR COLLEGE Newport, R.I.

Operational Art Exam

Evolution of the Operational Idea – from Midway to the Marianas & How Functions and Factors interacted during Operation Forager

By

Ben L. Anderson LCDR USN

A paper submitted to the faculty of the Naval War College in partial satisfaction of the requirements of the Joint Military Operations Department course in Joint Maritime Operations. The contents of this paper reflect my own personal views and are not necessarily endorsed by the Naval War College or the Department of the Navy. Date: 07 APR 2015 JMO 2015 LCDR Ben L. Anderson Ben.Anderson@USNWC.edu

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Starting from the "date which will live in infamy," and ending on the decks of the USS

Missouri, the United States military dramatically changed. While some of the changes were

physical (the size and technology possessed), the predominant change was the development of

the art of warfare which led to the eventual defeat of the Japanese. From the lessons learned in

the Battle of Midway, through the "Marianas Turkey Shoot," our military leaders honed their

skills, learned from their mistakes, and improved through each encounter with the enemy. The

comparison between the operational idea behind the battle at Midway and Operation Forager

exhibits this change in maturity quite clearly. Further, by examining the way the United States

applied the operational functions of Intelligence and Fires to leverage the operational factors of

time, space and force in Operation Forager, the extent of this maturity is readily recognized.

This paper begins with a comparison of the elements of the operational idea behind the Battle

for Midway and Operation Forager. This is followed by a discussion of the operational functions

of Intelligence and Fires to include how they were leveraged in Operation Forager to shape the

inevitable Japanese response and leverage the operational factors of time, space and force.

When one discusses the concept of operational idea, the elements of an operational idea as

defined by Vego in one of his several books can be used. While Vego lists them slightly

differently in at least three of his books (Joint Operational Warfare - Theory and Practice,

Operational Warfare at Sea - Theory and Practice and Major Naval Operations (Newport Papers

#32)), they are very similar. For the case of this paper, the elements as discussed in Joint

Operational Warfare - Theory and Practice will be used. In the analysis and comparison of the

elements of the operational idea behind Operation Forager to that of the Battle of Midway, it is

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clearly evident only now how much the United States matured in its understanding of modern

naval warfare.

To see this maturity, it is essential to examine the objectives behind each battle and examine

how they shaped the decision making process. For Midway, the objective was simple - do not let

the Japanese establish a foothold. Midway was a defensive operation which was critical to ensure

that American combat power could be built up in the region, and to ensure that Hawaii remained

available to US forces. For Operation Forager - it was the culmination of the Campaign Plan

Granite. Admiral King stated there were four primary objectives in this endeavor: (1) interdict

the Japanese sea lines of communication, (2) secure basing facilities for long range air attack of

the Japanese mainland, (3) secure basing for naval operations which would be used for

penetration into Japanese home waters, and (4) isolate and neutralize the Japanese forces based

in the Carolines.

The first element to examine is that of the use of selected principles of war. In Operation

Forager and Spruance's reaction to the Japanese response (A-Go), Spruance leveraged the

concepts of objective, unity of command, unity of effort, and restraint. For the objective,

Spruance understood the strategic significance of the taking of Saipan, Tinian and Guam, and

how through that action, final victory over the Japanese would be enabled. It was for this reason

he was able to exercise restraint when urged to pursue a decisive battle with the Mobile Fleet,

choosing instead to ensure the safety of the landing force. Despite differing opinions by senior

officers within the Task Force, unity of command was maintained, thereby ensuring unity of

effort in achieving Spruance's goals. In the battle of Midway, Spruance also showed restraint,

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choosing not to press the advantage by pursuing his enemy at night - knowing that the Japanese

ships were not only more capable craft, but the crews were trained in night engagements.

Further, the principles of surprise and being on the offensive were leveraged at Midway contrary

to their lack of use in the Marianas. The ability to put the ships to sea, to maintain radio silence

to prevent detection, then the unquestionable good fortune of the Japanese submarines arriving

too late to their positions to detect them all allowed for the inferior and outnumbered force to

overcome the Japanese assault at Midway.

Operation Forager truly leveraged the element of sequencing and synchronization that were

completely absent at Midway. Where Midway was a reactive plan, developed in a relatively

short time period, to only ensure that the Japanese did not establish a foothold near Hawaii,

Operation Forager was a significant portion of Campaign GRANITE. Operation Forager used

sequencing to establish the order in which Saipan, Tinian and Guam would be attacked, and

synchronization when suppressing the land based aviation in Guam and preventing the Mobile

Force to obtain a safe haven for landing following their attacks on Spruance's Task Force.

Unlike the previous elements, the element of deception was essential to the success at Midway,

whereas it did not play a significant role in Forager. At Midway, with the deployment of a much

larger fleet than expected by the Japanese, combined with strict operational security, the

concentration of force the United States was able to muster completely surprised the Japanese.

At Midway, the United States neither had the power nor the time to effectively use operational

fires to achieve a significant effect, while in Operation Forager it played a critical role. Through

operational fires, the United States virtually shaped the Japanese force. This was done through

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the destruction of the majority of the Japanese's land based aviation, disruption of their sea lines

of communication (restricting the availability of refined oil for fuel), and the disruption to the

resupply and reinforcement efforts to Japanese garrisons already entrenched in the Marianas. The

use of tactical fires early in the Midway battle was unable to achieve an operational effect as the

effort was poorly coordinated, the targeting ineffective, and had it not been for bad decisions on

the Japanese side, most likely would have been disastrous for the United States.

The use of operational pauses was a vital improvement to the operational idea of Operation

Forager compared to Midway. Spruance, having learned from Midway the challenges of trying

to fight a battle while constrained by fuel, ensured not only were sufficient operational pauses

implemented in his plan, but moved them as necessary to leverage the operational tempo in his

favor. Additionally, the efficiency at refueling and resupplying at sea during these operational

pauses greatly increased combat potential of Spruance’s force.

In the element which discusses the protection of the friendly center of gravity, it is essential to

note what each commander had determined as their center of gravity (CoG). In the case of

Operation Forager, Spruance determined that his CoG was the landing force, and ensured that his

forces stayed within range to ensure their defense. This was similar to the effort by Nimitz at

Midway to ensure that the carriers remained relatively safe.

Comparatively to Midway, Spruance did not have a significant worry about the regeneration of

combat potential during Operation Forager. He outnumbered the Japanese significantly and had a

more technologically advanced and proficient fighting force than Admiral Ozawa and the

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Japanese mobile force. The only time Spruance needed to regenerate combat potential was prior

to the landing in Guam, due to unexpected and fierce resistance at Saipan. At Midway, while

Nimitz would have greatly appreciated the ability to regenerate combat potential, there were

insufficient forces available at that time to support him.

The use of branches and sequels was another facet used within Operation Forager which was

neither used nor required at Midway. At Midway the task was simple - not to let the Japanese

establish a foothold. In Operation Forager branches were used to allow for flexibility in the plan

to take advantage of the tactical situation (choice of beach landing areas based on established

Japanese defenses). Sequels were also used to provide for a concentration of force at each of the

tactical objectives (the choice to assault Saipan, then Guam, then Tinian).

At Midway, Nimitz assessed that the carrier force of the Japanese was their CoG, and made

every effort to target those ships before anything else. Interestingly enough, Yamamoto at this

point believed that his battleships were his CoG. In the battle with the Japanese in the Philippine

Sea, Spruance also assessed that the Japanese carriers were the CoG of the Japanese, but chose

not to focus his effort in attacking them directly, but to defeat the Japanese air forces as they

attacked, remaining in position to cover his own operational CoG - the landing force.

This brings into the assessment how in each battle the method for defeating the enemy CoG was

implemented. In Midway, it was through sheer tenacity and luck (and bad decisions on the

Japanese's part) that the United States was able to defeat the Japanese through inflicting

sufficient damage on the Japanese carrier force. In the Philippine Sea - it was through the almost

total destruction of the Japanese air forces alone that victory was achieved.

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The final element to be examined is that of the use of operational reserve. In the case of

Midway, there was not much depth to the bench for the United States. Virtually all the force that

could be mustered was utilized in the battle. In the Philippine Sea, there was never a need for an

operational reserve when confronting the Mobile Force. While the engagements were so one-

sided, the need for an operational reserve didn't exist, but in fact did - as Spruance had sufficient

forces spread out to ensure the protection of the landing force, they could be called upon if

needed. An operational reserve did exist for the landing force, and upon disembarking them onto

Saipan, Spruance felt that he then could pursue the Japanese fleet.

There were many differences between the operational idea of the Battle of Midway and that of

Operation Forager. These differences were based on the new maturity of understanding in

modern naval warfare, and on the technological and numerical superiority of US forces. With a

solid understanding of the elements of the operational idea behind Operation Forager in hand,

one can now examine how the operational functions of intelligence and fires were leveraged by

the United States to shape the operational factors of space, time and force to its own advantage.

The use of intelligence played a crucial role in this shaping of the operational factors during

Operation Forager. First, despite the vastness of the space involved in conflict, both human

intelligence (HUMINT) and communications intelligence (COMINT) were leveraged to

effectively shrink the battlespace. Using HUMINT acquired from Philippine workers, the United

States was able to keep track of much of the Japanese fleet. Then, through the use of both

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submarines and radio direction finding stations scattered throughout the Pacific allowed for the

tracking of the Japanese fleet throughout the area.

COMINT was also leveraged to understand the Japanese force structure. Through the breaking

of Japanese codes and the intercept of their classified messages, the United States had a

considerable understanding of their composition and capabilities. This plethora of information

did however, lead Spruance to the wrong conclusion that the Japanese would attempt to conduct

an "end-run" on the landing force. This conclusion is the reason Spruance did not aggressively

pursue the Japanese fleet at the onset of the battle, as Spruance was determined to protect his

operational CoG (the landing force) from an "end-run" attack.

The use of radar for early warning played a vital role in the factors of both time and force.

Through the early identification of inbound enemy aircraft, which allowed sufficient time to get

defensive aircraft aloft, to the radar guided coordinated attack by our own forces (which

essentially acted as a force multiplier), radar was invaluable to Spruance and his fleet.

Aside from the use of intelligence, the use of fires also played a vital role in the shaping of the

factor of force.

From the cumulative effects of the previous operations of campaign plan GRANITE, to the

continued action by Admiral Lockwood and the submarine force, the Japanese forces Spruance

faced in the Philippine Sea were the product of American action. First, the indirect fires against

Japanese shipping and oil supplies had forced the Japanese to be very conservative on their use

of fuel - preventing much of the training they needed from occurring. Further, it forced the

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Japanese to resort to the use of crude oil, which was inherently more dangerous to use due to the

high sulfur content. Second, the sustained effort from January through May of 1944 to disable

the land-based air assets, bases, strong points and shipping in the region denied the Japanese

crucial forces which had been previously relied upon in their Z-Plan.

Finally, in the last months leading up to the invasion of Saipan, the constant attrition of forces

and supplies the Japanese attempted to deliver to the islands played a substantial role in

mitigating the defensive capabilities of the garrisoned forces.

While the use of intelligence and fires played a role in shaping the operational factors, they

obviously could not shape them perfectly to Spruance's needs. Despite not being able to shape

them perfectly, the United States exploited each of the factors of space, time and force, as

thoroughly as possible to ensure their victory over the Japanese.

The operational factor of space had several key elements which need to be examined to

understand its effect in the overall war effort. First, the geographically strategic position of the

Marianas was crucial to the overall war effort. This position, as stated in the discussion of the

objectives above, would play a vital role in the effort to force the unconditional surrender of

Japan through providing basing from which both long range bombers and naval forces would be

able to assault the Japanese mainland.

While the operating space was effectively shrunk by the use of intelligence, it was still a vast

space which itself presented challenges to Spruance and his task force. Due to the openness of

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the area, the Japanese had ample open ocean in which they could maneuver, which made it

challenging to find them between radio intercepts and submarine detections. The Japanese also

had a longer operational reach due to the aircraft design, which allowed for them to place their

CoG outside the reach of Spruance's carrier based aviation. Further, while the Japanese were free

to maneuver, Spruance effectively tethered himself to the landing forces to ensure the safety of

his operational CoG.

One area in which the vastness of the battlespace was to the benefit of Spruance was facilitated

by the decision of Ozawa to place his Force "C" 100 miles ahead of his carrier group -

effectively removing any ASW protection. This later facilitated the attack and sinking of two

vessels in Ozawa's fleet.

Another key element which shaped the battlespace was that of the weather. The direction of

winds were to the advantage of the Japanese, allowing them to drive towards Spruance's TF

while launching and recovering aircraft. Spruance, on the other hand, had to burn fuel and

constantly reposition to ensure sufficient wind across the deck.

Unlike the factor of space which did not provide either side a definitive advantage, the factor of

time was vastly in favor of the United States. From the initial planning of Campaign GRANITE,

to the expedited schedule set into motion due to concerns about typhoon season, the United

States had the advantage and momentum. The Japanese had to abandon their Z-plan as they did

not have sufficient time to prepare in light of the accelerated pace the United States was moving

through the Pacific. The Japanese were denied the training time desperately needed to train their

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pilots and their new ship commanders to acquire the combat skills their plans relied on. This

increased operational tempo (along with the use of operational fires) denied the Japanese time to

reinforce their garrisons, complete their runways, and build up supplies to provide for their

desired decisive battle.

Time was both a positive and negative factor in tactical operations. As a positive factor, due to

the attrition rate of Japanese forces, time was of great benefit, as the Japanese culminated

quickly. Conversely, time limited American flight operations due to the lack of proficiency at

night landings. Finally, as discussed above - the use of improved radar allowed sufficient time to

launch aircraft on detection of Japanese assault waves.

At the time of Operation Forager, the United States had both the technological and numerical

edge over the forces the Japanese could muster. Spruance's task force maintained substantial

defensive combat power due to the experience of pilots, superiority of aircraft, communication

abilities and use of radar for both detection and coordination of attack against enemy aircraft.

This was further enhanced through outstanding combat discipline. The teamwork exhibited by

the pilots in the response to the waves of assaults aided in battle becoming known as "The

Marianas Turkey shoot."

Spruance’s force contained substantial inherent defensive combat power due to the experience

of pilots, superiority of aircraft, communication abilities and advanced use of radar. As to the

experience of the pilots, the United States’ paradigm for pilot training was demonstrated yet

again as extremely advantageous. All of the US pilots had significantly more experience than the

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Japanese counterparts. This experience combined with the technological innovations for anti-air

defense batteries and radar systems allowed for a much higher latent combat power than the

Japanese. The combat power was able to be maintained through ensuring the recovery of

downed pilots (which provided a significant long term advantage) and the efficiency and

proficiency of the refueling at sea capabilities of the fleet.

Operational leadership of Spruance - while sometimes questioned - was outstanding. His focus

remained the strategic goal of taking Saipan vice being lured into a possible trap by the Japanese,

despite arguments from his team. Further, Spruance prioritized actions to ensure the long-term

success of the campaign through actions such as the recovery of downed pilots.

In examining the interaction between the operational factors, a space-force relationship can be

seen in the way forces were employed in response to the Mobile Force attack. The landing force

was occupied on Saipan, along with a protective task force, while the bulk of Spruance's forces

engaged the waves of incoming aerial waves while simultaneously striking the Japanese facilities

on Guam. The space-time interaction was evident on the decision to adjust GRANITE's timeline,

to ensure that most of the action in the Marianas would be complete prior to the start of typhoon

season (July). The time-force relation can be seen through the delay to assault Tinian and Guam

due to the strong defense presented at Saipan.

It was clearly through a detailed comprehension of the operational factors of space, time and

force that the United States was able to conduct such massive and complicated operations in the

Pacific in 1944. Leveraging the inherent understanding of these operational factors and using

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some of the operational functions with a ruthless efficiency, the United States was able to shape

the battlefield by not only effectively deciding when and where to fight, but what the Japanese

were going to be able to fight with. This would not have been possible had it not been for the

maturity in operational art which developed over the course of the war. From the infant stages of

operational art as expressed by the operational idea at the battle of Midway, to the efficiency and

solidity of the operational idea behind operation Forager, the world saw that the United States

was a mature, professional, fighting force.