AUTHOR Major B. T. Fenlon, USMC
SUBJECT AREA - History
TITLE: REMEMBER MIDWAY
I. Purpose: To analyze the development of the operations
plan for the invasion of Midway and to determine if that plan
held any inherent flaws which caused it to fail so disastrous-
II. Thesis: In spite of the fact that the Japanese Navy
possessed overwhelming combat power at Midway, it lost the
battle because of a plan built on erroneous assumptions,
tainted by a sense of invincibility, and supported with in-
III. Data: In 1921 Japan became a party to an agreement
which limited the size of her navy to sixty percent of the
size of the U.S. Navy. This restriction caused the Japanese
naval planners to reevaluate the traditional naval tactics
and to adapt them to their current situation. The tradition-
al concept of the decisive battle, where one fleet would en-
gage another seeking to destroy it in the process, was no
longer completely feasible for Japan. Thus, the concept of
the "diminution operation" evolved. Its basic tenet was that
the smaller Japanese Fleet would pare down its enemy's navy
by conducting surprise attacks using destroyers, aircraft, and
submarines. Once the enemy fleet was cut down, the Imperial
Navy would then seek to engage it in a decisive battle. This
would be conducted primarily using battleships. In this man-
ner, the carrier forces of the Imperial Navy were relegated
a subordinate role. This philosophy was prevalent in the
Naval General Staff at the outset of WWII; it affected the
strategic planning of naval operations,which were ultimately
directed toward Midway. The plan to attack Midway was pressed
on the Naval General Staff, by Adm. Yamamoto, against its
strong opposition. It was conceived by blindly overconfident
planners, who based it on an erroneous assumption: the Imper-
ial Navy would be able to achieve tactical surprise in this
attack. The plan never addressed the contingencies, which
would eventually cause its failure.
IV. Conclusion: The attack on Midway ended in disaster for
the Imperial Navy, because the operations plan which brought
it about was ill-conceived, inflexible, and lacked vital in-
Thesis: In spite of the fact that the Japanese Navy possessed
overwhelming combat power at Midway, it lost the battle be-
cause of a plan built on erroneous assumptions, tainted by a
sense of invincibility, and supported with inadequate intel-
I. Philosophy of Japanese Imperial Navy
A. Decisive Battle
B. "Diminution Operation"
C. Battleship Navy
II. War Strategy
A. Strategy options
1. West to Ceylon
2. South to Australia
3. East to Hawaii
B. Midway chosen
III. Operation MI
IV. Flaws within Operation MI
A. Erroneous assumptions
B. Relaxed operational security
D. Shallow reconnaissance planning
V. Inevitable Outcome
In early June of 1942 the fleets of the U.S. Navy and
the Imperial Japanese Navy met approximately 1200 miles north-
west of Hawaii near a pair of tiny islands known as Midway.
The battle which ensued became the turning point in the Pacif-
ic War; its outcome determined the course of the war there-
after. The results were puzzling in view of the forces in-
volved. The Japanese Fleet operating in the immediate vicin-
ity of Midway included six carriers, eleven battleships,
sixteen cruisers, and fifty three destroyers, while the U.S.
Fleet consisted of three carriers, seven cruisers, and seven-
teen destroyers.1 In spite of the fact that the Japanese Navy
possessed overwhelming combat power at Midway, it lost the
battle because of a plan built upon erroneous assumptions,
tainted by a sense of invincibility, and supported with in-
To understand the rationale of Japan's Naval General
Staff in conducting the early war, one must look back to the
surprise attack on Pearl Harbor, which took place six months
prior to Midway, and to the philosophy which prompted it.
The attack on Pearl Harbor was designed to destroy the U.S.
Pacific Fleet. This attack, which was well conceived and
skillfully executed, was not completely successful; it failed
to strike the carrier forces, because they were at sea. The
failure to damage any of the carriers left some unfinished
business, because they represented a tremendous threat to
Japan's naval forces.
The philosophy which formed the Japanese Naval General
Staff's thinking was a variation on the traditional philos-
ophy of the decisive battle. The decisive battle was one in
which the naval forces of one nation met the majority of the
naval forces of another; the outcome of this encounter resulted
in the destruction or capture of the other nation's navy.
This time-honored concept was exemplified in May 1905, when
the Russian Fleet was overwhelmed by the Japanese Fleet in the
Strait of Tsushima. However, strict adherence to the concept
of the decisive battle no longer seemed feasible for Japan.
In 1921 Japan agreed to the tenets of the Washington Con-
ference which restricted the size of her navy to sixty percent
of the tonnage of the United States' capital ships. This
agreement was renewed by the London Conference of 1930. Be-
cause Japan's navy was to be smaller than that of her poten-
tial adversary, the Naval General Staff was forced to recon-
sider this idea of the decisive battle. "Therefore, our navy
modified its strategic policy from one of the `decisive bat-
tIe' to one of the `diminution operation.'"
The "diminution operation" was a strategy of judicious
This operation involved the adoption of a policy of
"offensive defense." Our major units were to remain on
the defensive strategically... .Meanwhile, our forces of
submarines, destroyers, and aircraft were to go into ac-
tion and inflict such damage upon the enemy as to bring
about parity between the two main forces. At this point
the "decisive battle" would be fought.3
This concept was characterized by air strikes using land-based
and carrier aircraft, submarine attacks, and night engagements
employing destroyers. The battleships were still considered
the strategic force, which would be the key to the decisive
Much to the chagrin of the Japanese naval aviators, the
aircraft carriers-were viewed as having primarily a subordi-
nate role to the battleships. Emphasis was placed on arming
them solely with dive bombers and torpedo planes. However,
in the mid 1930's this concept was strongly contested. One
of the primary challengers, who was then a student at the
Naval War College, was Cdr. Minoru Genda. He proposed that
the battleship force be abolished and replaced with aircraft
carriers. His reasoning was based on the results of previous
naval exercises and war games, which continually demonstrated
that the larger force, assuming a similar composition, emerged
victorious. He further argued that battleships could be sunk
by aircraft alone. As a corollary, because battleships could
be sunk by aircraft, enemy battleships would never come within
range of their own; thus, they were obsolete and would only
serve as targets for enemy aircraft.5
Similar arguments were put forth by other officers within
the Naval Air Corps. Cdr. Mitsuo Fuchida, a classmate of Cdr.
Genda's, came to a similar conclusion. "Battleships rather than
carriers constituted the main battle strength of the Fleet.
Instead of employing the battleships to screen and reinforce
the carriers, it was the carriers which were placed in the sup-
porting role."6 Such radical arguments encountered strong op-
position within the hierarchy of the Imperial Navy and were
overall disregarded. Such disregard of this evolutionary
thinking would reap disastrous consequences at Midway.
When the Japanese initiated hostilities at Pearl Harbor,
they were exercising their tactical concept of the "diminu-
tion operation." The destruction of the Pacific Fleet bat-
tleships was the result. The Imperial Navy had succeeded in
paring down the Pacific Fleet, so that "...the Pearl Harbor
operation did achieve its strategic objective of preventing
the U.S. Pacific Fleet from interfering with the Japanese op-
erations in the south. Yet in spite of this tremendous
success, there was still a persistent concern regarding the
survival of the U.S. Navy's aircraft carriers.
From the time of the attack on Pearl Harbor until May
1942, Japan's armed forces were busy, especially the Imperial
Navy's Carrier Striking Forces. The Japanese Empire extended
to the southwest to Borneo, including the conquest of Burma,
Thailand, and the Malay Peninsula down to Singapore; to the
south into the Philippines and down to the Dutch East Indies;
and to the east including Guam, Tarawa, and Wake Islands.
The carriers engaged in four major operations ranging from the
mid-Pacific to the Indian Ocean. The results of these engage-
ments were numerous successful air raids , in addition to the
sinking of seven warships from the British, U.S., and Austra-
lian Fleets. Meanwhile, a large portion of the Japanese Fleet,
including the battleships, lay idle in the home waters.
The primary focus in expanding the Empire was to gain the
necessary raw materials and oil to sustain the nation and her
military efforts. Having succeeded in that endeavor the nation
was somewhat at a loss regarding where to project her further
At the start of the Pacific War, Japan's strategy-makers
had been so engrossed in the immediate problem of acquir-
ing oil resources that they had formulated no concrete
strategic program for the ensuing course of hostilities
after these resources had been won. Also, they had been
keenly conscious of the many risks involved in the ini-
tial operations...and had been by no means certain of the
outcome. They therefore had decided to wait and see how
the operations progressed before attempting to formulate
subsequent war strategy.
The future course of operations held several options for
the Japanese strategists. The Japanese forces could continue
to operate offensively with the ultimate goal of demoralizing
the Allied forces to the point of forcing a quick cessation
of the hostilities. Alternatively, Japan could go on the de-
fensive in an effort to protect the vast territory and wealth,
which she had already gained. The proponents of continuing
to operate offensively won out over those leaders who recom-
mended shieding her acquisitions.
Operating under the premise that Japan would continue to
expand her conquests, the strategic planners had to determine
the direction, which further advances would take. Basically,
there were three paths from which they could choose; they
could advance southwest toward Ceylon, south toward Austra-
lia, or east toward Hawaii. Because the Japanese Army argued
that it could not support an operation in Ceylon, due to a
perceived threat from the Soviet Union, that option was re-
jected outright. The choice between Australia and Hawaii was
Within the organization of the Japanese Imperial Navy
there were two strategy planning staffs: the Naval General
Staff and the Combined Fleet Staff. The Chief of the Naval
General Staff was Adm. Osani Nagano. His staff favored a move
toward Australia, because it represented a serious threat to
Japan's southern flank. The staff reasoned that Australia would
be used as the line of departure for an Allied counteroffen-
sive. Thus, to protect her perimeter Japan would have to iso-
late Australia, thereby severing the sea line of communication
with the United States.9
The Combined Fleet Staff, under Adm. Isoroku Yamamoto,
exhorted a thrust toward Hawaii. Yamamoto's argument was
based on two premises. First, if Midway was attacked, the
survivors of the Pearl Harbor attack would be drawn out to
defend it; such an event would present the Imperial Navy the
opportunity to engage the remnants of the U.S. Pacific Fleet
in a decisive battle. Second, that the occupation of Midway
would allow the establishment of an observation post and serve
to strengthen Japan's eastern flank.10 Midway had great stra-
tegic value; it "...offered to whoever held it the opportunity
of controlling the central Pacific through its air, sea, and
communications link to Hawaii."11
The debate between the two staffs began in earnest in the
first week of April 1942. The Naval General Staff presented
its major arguments against the Midway operation:
1. Because Midway was close to Hawaii its defenses
could be easily reinforced; as a result of the attack
on Pearl Harbor the Japanese Fleet was unlikely to
2. The Japanese forces would be operating without the
benefit of land-based air support.
3. Could Japan afford to defend and supply Midway, if
it was successfully occupied?
4. There was currently a shortage of aircraft.12
In spite of the Naval General Staff's misgivings, the Combined
Fleet Staff pressed home its arguments,so that Nagano's staff
ultimately acquiesed to Yamamoto's urgings.
On 18 April an event took place which served as a power-
ful reinforcement of Yamamoto's strategy for attacking Midway.
A squadron of B-25's, which were launched from aircraft car-
riers 700 miles away, bombed Tokyo and several other Japanese
cities. The physical damage which the raid inflicted was in-
significant; however, the consternation which the attack caused
was measurable. The raiders, led by Lt.Col. Doolittle, man-
aged to slip through Tokyo's air defenses. This strike was a
slap in the face to the Japanese military leaders; Yamamoto
was humiliated; he felt he had personally failed to protect
his Emperor. This foray steeled the resolve of the Imperial
Navy to seek out and destroy the U.S. Pacific Fleet.
The basic plan, designated Operation MI, involved an am-
phibious assault to secure Midway; it would take place on
7 June. The assault would be preceded by a massive air attack
against the airfields and installations on Midway. Preceding
the attack on Midway, an element of the Combined Fleet, des-
ignated as the Northern Force, would strike and capture Attu,
Adak, and Kiska in the Aleutian Islands. This assault was
designed to destroy the military installations there and to
serve as an outpost in order to bolster Japan's northern flank.
In addition, it would serve as a diversion for the main attack
at Midway. At the time the Midway operation was conceived,
the planners had seven heavy aircraft carriers available to
employ against the supposed four, which the Americans could
To support Operation MI the staff devised an elaborate
reconnaissance plan employing two separate elements. The first
element involved two long range seaplane bombers which were
to conduct deep reconnaissance, concentrating on the Fleet
activities at Pearl Harbor. They would depart from Wotje, in
the Marshall Islands, refuel from submarines, and reconnoiter
Pearl Harbor. Upon completing this mission, they would re-
turn to Wotje and report their findings. This mission was
scheduled for 31 May - 3 June. The second element of the
reconnaissance plan involved the Submarine Force, which was
to establish two cordons to the east of Midway. The submarines'
task was "...to report any enemy warships coming out of Hawaii
. . .then intercept and sink them."13 This force was to be in
position by 2 June.
The Combined Fleet would sortie between 27-29 May from
the Japanese home waters and advanced bases located in the
Mariana Islands. The mission for the main attack included
two specific objectives: first, the seizure of Midway for
use as an advanced air base; second, the drawing out of the
U.S. Pacific Fleet to engage and destroy it. According to
Yamamoto's staff the priority was placed on the first objec-
tive. On one occasion Cdr. Genda queried Capt. Kuroshima, a
senior staff officer, regarding Yamamoto's true intent.
Kuroshima affirmed, "`The primary mission of the task force
is to support the Midway invasion.'"14 Yamamoto's priority
caused serious concern among many of the other officers with-
in the Combined Fleet.
In creating this plan the one, key assumption was that
the Combined Fleet would achieve tactical surprise in execut-
ing this mission. The invasion of Midway would be well under
way before the Pacific Fleet could possibly arrive on the
scene. The issue of surprise was never seriously challenged
by any of the staff. "Combined Fleet planners completely
failed to provide for the contingency that the enemy might
somehow learn of our intentions in advance and thus be able
to deploy his forces for an ambush attack."15 During the war
games which preceded the operation, a question was raised re-
garding the Fleet's plan to meet the possibility of U.S. car-
riers appearing while the Japanese carriers were conducting
strikes on Midway. The staff had no adequate response, nor
did it appear to have devised one subsequently.16
Assuming that the Combined Fleet surprised the U.S.
forces by attacking Midway, the two primary objectives of the
operation were attainable. Yet, if the U.S. Navy had been
forewarned and had deployed its carriers, then the two objec-
tives would become antithetical. In one case, the Fleet's as-
sets would be tied to supporting the invasion, which had the
higher priority. While the other case would require that the
Fleet attack the enemy carriers to accomplish its secondary
objective and to ensure its own survival. Now the Commander
of the Carrier Striking Force, Adm. Nagumo, would have a
dilemna to act upon. Under the best possible case he would launch
his aircraft against the enemy carriers. However, he might
not have that option, if his forces were already engaged in
attacking Midway, in which case, he would be highly vulner-
Ironically, the key to the Combined Fleet's success was
also the key to its ultimate defeat. While the staff finalized
and issued its plan, the U.S. Navy's cryptanalysts were work-
ing frantically to decipher and piece together intercepts of
this plan. By early May Adm. Nimitz was aware that the Jap-
anese were planning a major operation, probably against Mid-
way. (In March and April of 1942, the U.S. Navy specialists
had begun-to break the Imperial Navy's operational code.)
Security surrounding the operation became a real concern for
the Japanese. Prior to the Pearl Harbor attack security had
been paramount, but it seemed to be less strict for this op-
eration. Cdr. Fuchida voiced his concern to Cdr. Genda as
the Combined Fleet sailed "`...One thing worries me is the way
information about the sortie has leaked out. Everybody seems
to know about it.'"17
The United States was most fortunate in that portions
of the force designated to attack Midway were forward based
in the Mariana Islands. As a result, U.S. Navy communicators
intercepted the bulk of the operations plan for the Midway
offensive. Ironically, Genda, as well as other senior of-
ficers, had recommended that the Fleet deploy and initiate
this operation from a forward base. Due to a time schedule,
which was deemed critical to meet, this suggestion was re-
A high degree of inflexibility began to manifest itself
within the Combined Fleet Staff once the plan was generated.
As it was previously mentioned, the set schedule would be ob-
served. This rigidity was due in part to the psychological
impact, which the Doolittle raid had on Yamamoto. Following
the conduct of the Midway war games, the Battle of Coral Sea
took place. The outcome resulted in the loss of an entire
carrier division, consisting of two heavy carriers, for the
Midway operation. despite a significant reduction of its
offensive striking power, the Combined Staff neither delayed
the action nor realigned the composition of its forces.
Coupled with this inflexibility in the planning of Oper-
ation MI, there was strong evidence of an unhealthy overcon-
fidence developing within the staff. The basis for this
fault was the unprecedented string of victories which Japan's
military forces had amassed since Pearl Harbor. Fuchida
termed the psychological result of their successes as the
"Victory Disease." 18 The basic plan never really considered
the possibility of the Pacific Fleet lying in ambush, nor
did the war games, which tested it, allow for the enemy to
project any real offensive power, once it arrived in the area.
This overconfidence was not limited to the planners, rather
it infected the operational forces to the extent that they
felt they had little to fear from the enemy. Fuchida sum-
marized this conceit aptly: "We were accustomed to success
and so sure of our superior strength that no thought was
given to the possibility that things might not go exactly as
The execution of Operation MI suffered drastically from
the shortcomings of the reconnaissance plan, which was design-
ed to support it. The two primary means of gathering intel-
ligence for the operation revolved around the use of the long
range seaplanes and the establishment of the submarine cor-
dons between Midway and Hawaii. This plan was aggressive but
shallow; it never addressed the possibility of these elements
failing to complete their missions. In fact, the long range
reconnaissance by the seaplanes had to be cancelled, because
two U.S. Navy ships were stationed at the refueling point.
The submarine cordons were established two days late, because
overhaul repairs had delayed this force's departure. The sub-
marines missed the passage of the Pacific Fleet. Thus, the
Imperial Navy was operating without any long range surveillance.
It no longer enjoyed the luxury of having diplomats located
in Hawaii to monitor and report the activities of the Pacific
Fleet, as it did prior to Pearl Harbor.
A further intelligence gap developed during the execu-
tion, when Yamamoto's flagship intercepted radio traffic from
Pearl Harbor, which indicated the possible sortie of the Pa-
cific Fleet. Yamamoto, operating 300 miles behind the Carrier
Striking Force, neglected to relay this critical information
to Nagumo, who had not picked it up. The coup de grace was
administered by the Naval General Staff, which reported that
radio intercepts indicated that the American carriers were
operating in the vicinity of the Solomon Islands, well out
of the picture. This information came courtesy of Adm.
Nimitz, who had stationed a cruiser in the Solomons for the
sole purpose of creating a deception.
The outcome of the engagement at Midway has been well
documented. Beyond the destruction of a major portion of the
Imperial Navy's Carrier Striking Force, this decisive battle,
which the Japanese had so long sought, ended Japan's offensive
operations. From this battle the Imperial Navy would never
fully recover. Yet, from its inception Operation MI was
doomed to fail. It was conceived by planners who were blind-
ly overconfident, who based it on outmoded tactical concepts
and erroneous assumptions, and who were reacting to ill-de-
fined national strategic goals. This plan's collapse was
assured, when the reconnaissance plan failed to support it.
The lessons of the failure of Operation MI must not be lost
in the pages of history.
1Gordon W. Prange,Miracle at Midway(New York: Penguin
Books, 1982) ,p. 128.
2Gen. Minoru Genda,JSDF,"Tactical Planning in the Imperial
Japanese Navy,"Naval War College Review(0ctober 1969),p.45.
6Capt.Mitsuo Fuchida and Cdr.Masatake Okumiya,Midway: The
Battle That Doomed Japan(Annapolis,Md.: U.S. Naval Institute,
10LtCdr.Thomas E. Powers,USN,"Incredible Midway,"U.S.
Naval Institute Proceedings(June1967),p.65.
11VAdm.William Ward Smith,USN(Ret),Midway: Turning Point
of the Pacific(New York: Thomas Y. Crowell Company,1966),p.66.
13LtCdr.Yahachi Tanabe,IJN,"I Sank the Yorktown at
Midway,"U.S. Naval Institute Proceedings(May,1948),p.60.
Buell, Thomas B. The Quiet Warrior: A Biography of Admiral
Raymond A. Spruance. Boston: Little, Brown and Company,
Ferrier, H. H. Lt., U.S. Navy. "Torpedo Squadron Eight: The
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(October 1964), 72.
Fuchida, Mitsuo Capt., IJN and Masatake Okumiya, Cdr., IJN.
Midway: The Battle That Doomed Japan. Annapolis, Md.:
U.S. Naval Institute, 1955.
Genda, Minoru Gen., JSDF. "Tactical Planning in the Imperial
Japanese Navy." Naval War College Review, (October 1969),
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Powers, Thomas E. LtCdr., U.S. Navy. "Incredible Midway."
U.S. Naval Institute Proceedings, (June 1967), 64.
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