Transcript of &OPERATION DOWNFALL [US invasion of Japan]:& US PLANS AND
JAPANESE COUNTER-MEASURES& by D. M. Giangreco, US Army Command and General Staff
Transcript of &OPERATION DOWNFALL [US invasion of Japan]:& US PLANS AND
JAPANESE COUNTER-MEASURES& by D. M. Giangreco, US Army Command and General Staff
College, 16 February 1998
From Beyond Bushido:& Recent Work in Japanese Military History a
symposium sponsored by the Center for East Asian Studies, the College of Liberal Arts and
Sciences, the Office of International Programs, and the Departments of History and East
Asian Languages and Cultures at the University of Kansas.& Monday, February 16, 1998.
B. TSUTSUI:& Our next speaker, D. M. Giangreco, is an editor for the US Army's
professional journal, Military Review, published by the Command and General Staff
College at Fort Leavenworth, Kansas.& Giangreco has lectured widely on national
security matters.& An award-winning author of five books on military and political
subjects, he has also written
extensively for various national and international publications on such topics as the
Falkland Islands' sovereignty question, decentralization of the Soviet Air Force command
and control structure, Persian Gulf pipeline construction to circumvent the Strait of
Hormuz bottleneck, and the human interface with rapidly changing technologies.
& Several of his works have
been translated into French, German and Spanish.& Giangreco's most recent books have
also been published in Japanese, and the next one, Dear Harry on the
correspondence of &everyday Americans& with the Truman White House will be
released in fall 1998 [NOTE:&
for more on DEAR HARRY].& Giangreco
is also being awarded the Society for Military History's 1998 Moncado Prize for his
article &Casualty Projections for the US Invasions of Japan: Planning and Policy
Implications& published in the July 1997 Journal of Military History by the
George C. Marshall Center and VMI.
GIANGRECO:& Thank you.& It's great to be here today.
The sudden and unanticipated conclusion of the Pacific War with the dropping of atom bombs
on Hiroshima and Nagasaki was greeted with joy by all Americans, and especially by the
more than three and a half million soldiers, sailors and Marines slated to invade Japan.
& These forces were not only to come from the P& First Army, which had
pummeled its way from Normandy to the heart of Germany, and Eighth Air Force, based in
England, were on the way as well.& But morale was not good among veterans of the
Ardennes, Guadalcanal, and other campaigns.& As James Jones later wrote: &What
it must have been like to some old-timer buck sergeant . . . [knowing] that he very likely
had survived this far only to fall dead in the dirt of
Japan's Home Islands, hardly bears thinking about.&
MacArthur's staff had twice come up with figures exceeding 100,000 casualties for the
opening months of combat on the southern island of Kyushu, a figure which some historians
largely succeeded in contrasting favorably- and quite mistakenly- with President Harry
Truman's much-derided post-war statement that Marshall had advised him at Potsdam that
casualties
from both the Kyushu and Honshu invasion operations could range from 250,000 to
one million men.
Truman and Marshall were intimately familiar with losses in the Pacific during the
previous year:& over 200,000 casualties from wounds, fatigue and disease, plus 10,000
American dead and missing in the Marianas, 5,500 dead on and around Leyte, 9,000 dead
during the Luzon campaign, 6,800 at Iwo Jima, 12,600 at Okinawa, and 2,000 killed in the
unexpectedly vicious fighting on Peleliu.& Both also knew that, save for some
operations around New Guinea, real casualties were routinely outpacing estimates and the
gap was widening.& They also knew that while America always emerged victorious,
operations often were not being completed as rapidly as planned- with all the added cost
in blood and treasure that such lengthy campaigns entailed.
Leyte is a perfect example.& Leyte was to the Luzon campaign what the Kyushu invasion
was to the capture of Honshu's Kanto Plain and Tokyo, a preliminary operation to create a
huge staging area.& Today, we can recall MacArthur wading ashore triumphantly in the
Philippines.& But what Truman and Marshall knew only too well was that MacArthur was
supposed to have retaken Leyte with four divisions and have eight fighter and bomber
groups striking from the island within 45 days of the initial landings.& However,
nine divisions and twice as many days into the battle, only a fraction of that airpower
was operational because of unexpected terrain conditions (and this on an island
which the United States had occupied for over forty years).& The fighting on the
ground not gone as planned.& The Japanese even briefly isolated Fifth Air Force
headquarters and also captured much of the Burauen airfield complex before reinforcements
pushed them back into the jungle.
Now, some historians have stated incredulously that Marshall's estimate of up to one
million casualties for the invasion of Japan significantly exceeded those sustained in
Europe.& But while the naval side of the Pacific War displayed the broad, sweeping
moves so loved by historians, land combat in the Pacific had little in common with the
maneuver warfare that went a long way toward keeping casualties comparatively low in
France and the central German Plain.& The closest European commanders came after
D-Day to the corps-level combat which was the stock and trade of Army and Marine divisions
in the Pacific was the prolonged fighting in the Huertgen Forest and Normandy's hedgerows-
close-in, infantry-intensive slugfests that produced many bodies on both sides.& It
is also important to note that when they went to Potsdam, Truman and Marshall knew that
total US casualties had recently exceeded the one and a quarter million mark- a number
these historians find unfathomable- what's more the bulk of the losses occurred in just
the previous year of fighting against Germany.
There were plenty of estimates which confidently asserted that strategic bombing,
blockade, or both- even the invasion of Kyushu alone- would bring Japan to its senses, but
no one was able to provide General Marshall with a convincing explanation of just how long
that would take.& The millions of Americans poised to take part in the largest
invasion in history, as well as those supporting them, could only stay poised for so long.
& Leaders in both Washington and Tokyo knew this just as well as their
theater commanders in the Pacific.& After learning of the bomb, MacArthur ignored it
save for considering how to integrate the new weapon into plans for tactical operations at
Kyushu and Honshu if Tokyo was not forced to the surrender table. Nimitz was of a similar
mind.& On being told that the bomb would become available in August, he reputedly
remarked, &In the meantime I have a war to fight.&
On 29 July 1945, there came a stunning change to an earlier report on enemy strength on
Kyushu.& This update set alarm bells ringing in MacArthur's headquarters as well as
Washington because it stated bluntly that the Japanese were rapidly reinforcing southern
Kyushu and had increased troop strength from 80,000 to 206,000 men, quote: &with no
end in sight.& Finally, it warned that Japanese efforts were, quote: &changing
the tactical and strategic situation sharply.&& While the breathless &no
end in sight& claim turned out to be somewhat overstated, the confirmed figures were
ominous enough for Marshall to ponder scraping the Kyushu operation altogether even though
MacArthur maintained that it was still the best option available.
Now, this is particularly interesting because, in recent years, some historians have
promoted the idea that Marshall's staff believed an invasion of Japan would have been
essentially a walk-over.& To bolster their argument, they point to highly qualified-
and limited- casualty projections in a variety of documents produced in May and June 1945,
roughly half a year
before the first invasion operation, Olympic, was to commence. Unfortunately, the numbers
in these documents- usually 30-day estimates- have been grossly misrepresented by
individuals with little understanding of how the estimates were made, exactly what they
represent, and how the various documents are connected.& In effect, it is as if
someone during World War II came across casualty estimates for the invasion of Sicily, and
then declared that the numbers would represent casualties from the entire Italian
campaign.& Then, having gone this far, announced with complete confidence
that the numbers actually represented likely casualties for the balance of the war with
Germany.& Of course, back then, such a notion would be dismissed as being laughably
absurd, and the flow of battle would speedily move beyond the single event the
original estimates- be they good or bad- were for.&& That, however, was
fifty-plus years ago.& Today, historians doing much the same thing, win the plaudits
their peers, receive copious grants, and affect the decisions of major institutions.
& [Laughter.]
The limited and cautiously optimistic estimates of May and June 1945 were turned to junk
by that intelligence estimate at July's end, and the situation was even more dangerous
than was perceived at that time.& War plans called for the initial landings on the
Home Islands to be conducted approximately 90 days hence.& But, as we shall see, the
invasion of Kyushu would actually have not been able to take place for anywhere from 120
to 135 days- a disastrous occurrence for the successful outcome of stated US war aims.
Some today assert, in effect, that it would have been more humane to have just continued
the conventional B-29 bombing of Japan, which in six months had killed nearly 300,000
people and displaced or rendered homeless over 8 million more.& They also assert that
the growing US blockade would have soon forced a surrender because the Japanese faced,
quote: &imminent starvation.& US Planners at the time, however, weren't nearly
so bold, and the whole reason why advocates of tightening the noose around the Home
Islands came up with so many different estimates of when blockade and bombardment
might force Japan to surrender was because the situation wasn't nearly as cut and dried as
it appears today, even when that nation's supply lines were severed.& Japan would
indeed have become, quote:& &a nation without cities,& as urban populations
suffered grievously under the weight of A but over half the population
during the war lived and worked on farms.& Back then the system of price supports
that has encouraged Japanese farmers today to convert practically every square foot of
their land to rice cultivation did not exist.& Large vegetable gardens were
a standard feature of a family's land and wheat was also widely grown.&
The idea that the Japanese were about to run out of food any time soon was largely derived
from repeated misreadings of the Summary Report of the 104-volume US Strategic
Bombing Survey of Japan.& Using Survey findings, Craven and Cate, in the multi-volume
US Army Air Force history of WWII detailed the successful US mine-laying efforts against
Japanese shipping which essentially cut Japanese oil and food imports, and state
only that by mid-August, quote: &the calorie count of the average man's fare had
shrunk dangerously.&& Obviously, some historians enthusiasm for the point they
are trying to make has gotten the better of them since the reduced nutritional value of
meals is somewhat different than &imminent starvation.&
As for the Imperial Army itself, it was in somewhat better shape than is commonly
understood today.& Moreover, the Japanese had figured us out. They had correctly
deduced the landing beaches and even the approximate times of both invasion
operations, and were thus presented with huge tactical and even strategic
possibilities.& And although the Japanese had never perfected central control and
massed fire of their artillery, this fact was largely irrelevant under such circumstances.
& The months that the Japanese Sixteenth Army had to wait for the first US invasion,
at Kyushu, were not going to be spent with its soldiers and the island's massive civilian
population sitting on their duffs.& The ability to dig in and preregister, dig in and
preregister, dig in and preregister, cannot be so casually dismissed.& To borrow a
phrase from a recent Asian war, the Kyushu invasion areas were going to be a, quote:
&target-rich environment& where artillery was going to methodically do its work
on a large number of soldiers and Marines whose luck had run out.& On Okinawa, the US
Tenth Army commander, General Buckner, was killed by artillery fire when the campaign was
ostensibly in the mopping-up phase, and from World War I to the recent fighting in Grosny,
where shells killed a Russian two-star general, there is ample evidence of artillery
living up to its deadly reputation.
It has also been stated that US ground troops didn't really need to worry about Japanese
cave defenses since combat experience in the Pacific, and tests run in the US, proved the
effectiveness of self-propelled 8-inch and 155mm howitzer against caves and bunkers as
well as their vulnerability to direct fire from tanks.& That the Japanese were also
well aware of this and were arranging defensive positions accordingly from lessons learned
on Okinawa and the Philippines is not mentioned.& In any event, the Japanese had
already demonstrated that they could, with the right terrain, construct strongpoints, like
Item Pocket on Okinawa, which could not be bypassed and had to be reduced without benefit
of any direct-fire weapons since no tanks- let alone lumbering self-propelled
guns- could work their way in for an appropriate shot.
Similarly, on the Japanese ability to defend against US tanks, Army and Marine armor
veterans of the Pacific war would be amazed to learn that they had little to fear during
the invasion.& After all, Japan's obsolescent 47mm anti-tank guns, quote:
& &could penetrate the M-4 Sherman's armor only in vulnerable spots at very
close range& and that their older 37mm gun was completely ineffective against the
Sherman tank.& In fact, the Japanese, through hard experience, were becoming quite
adept at tank killing.& During two actions in particular on Okinawa, they managed to
knock out 22 and 30 Shermans respectively.& In one of these fights, Fujio Takeda
managed to stop four tanks with six 400-yard shots from his supposedly worthless 47mm.
& As for the 37mm, it was not intended to actually destroy tanks during the invasions
but to immobilize them at very short ranges so that they would become easier prey for the
infantry tank-killing teams that had proven so effective on Okinawa.
Some historians are also somewhat more confident than on-scene commanders as to our
ability to pulverize Japanese defenses. This may be due, in part, to an overly literal
interpretation of what the Japanese meant by &beach defenses,& even though there
is ample documentation on their efforts to develop positions well inland, out of range of
the Navy's big guns.& One author, from the safe distance of five decades wrote:
& &That coastal defense units could have survived the greatest pre-invasion
bombardment in history to fight a tenacious, organized beach defense was highly
doubtful.&& I do believe something similar to this was confidently maintained
just before the Somme in 1916, and it is worthwhile noting that every square inch
of Iwo Jima and Okinawa was well within the range of the Navy's 8-, 12-, 14-, and 16-inch
guns during those campaigns.& [Murmurs and whistle.]
Points like these may sound rather nit-picky but they assume great importance when you
realize that, as noted earlier, the target date for Kyushu of 1 November 1945 was going to
get pushed back as much as 45 days, giving the Japanese as much as four and a half months
from the flashing red light of the 29 July intelligence estimate to prepare their
The Joint Chiefs originally set the date for the invasion of Kyushu (Operation Olympic) as
X-Day, December 1, 1945, and for Honshu (Operation Coronet) as Y-Day, March 1, 1946.
& To lessen casualties, the launch of Coronet would await the arrival of two armored
divisions from Europe to sweep up Honshu's Kanto Plain and cut off Tokyo before
the seasonal monsoons turned it into vast pools of rice, muck, and water crisscrossed by
elevated roads and dominated by rugged, well-defended foothills.
Now, long before the British experienced the tragedy of pushing XXX Corps up a single road
through the Dutch lowlands to Arnhem, an event popularized through the book and movie A
Bridge too Far, US planners were well aware of the costs that would be incurred if
the Kanto Plain was not secured for mobile warfare and airfield construction prior to the
wet season. Intensive hydrological and weather studies begun in 1943 made it clear that an
invasion in early March offered the best chance of success, with the situation becoming
more risky as the month progressed.
With good luck, relatively free movement across the plain might even be possible
well into April.& Unfortunately, this assumed that the snow run-off from the
mountains would not be too severe, and that the Japanese would not flood the fields.
& While subsequent post-war prisoner interrogations did not reveal any plans to systematically
deluge low-lying areas, a quick thrust up the Kanto Plain would not have been as speedy as
planners believed.& First, there were no bridges in the area capable of taking
vehicles over 12 tons.& Every tank, every self-propelled gun, and prime mover would
have to cross bridges erected for the event. Next, logistical considerations and the
sequence of follow-up units would& require that armored divisions not even land until
Y+10.& This would provide time for the defenders to observe that the US infantry's
generic tank support was severely hampered by already flooded rice fields and- shall we
say- suggest ways to make things worse for the invaders.
A late start on Honshu would leave American forces to fight their way up flood plains that
were only dry during certain times of the year, but could be suddenly inundated by the
Japanese.& If the timetable slipped for either operation, US soldiers and Marines on
Honshu would risk fighting in terrain similar to that later encountered in Vietnam- minus
the helicopters to fly over this mess- where all movement was readily visible from even
low terrain features and vulnerable convoys moved on roads above rice paddies.
Unfortunately, foul weather would have delayed base development on Kyushu and spelled a
potentially disastrous late start for the operation on Honshu.
Planners envisioned the construction of 11 airfields on Kyushu for the massed airpower
which would soften up Honshu.& Bomb and fuel storage, roads, wharves, and base
facilities would be needed to support those air groups plus the US Sixth Army holding a
110-mile stop-line one third of the way up the island.& All plans centered on
construction of the minimum essential operating facilities.& But that
minimum grew.& The 31- that's 31 - air groups was increased to 40 then to 51
- all for an island
on which there was considerably less terrain information available than we erroneously
believed we knew about Leyte.& Numerous airfields would come on line early to support
ground operations on Kyushu, but the lengthy strips and support facilities for
Honshu-bound medium and heavy bombers would only start to become available 45 days into
the operation.& Most were not projected to be ready until 90 to 105 days after the
initial landings on Kyushu in spite of a massive effort.
The constraints on the air campaign were so clear that when the Joint Chiefs set the
target dates of the Kyushu and the Honshu invasions for December 1, 1945 and March 1,
1946, respectively, it was apparent that the three-month period between X-Day, Olympic and
Y-Day, Coronet, would not be sufficient.& Weather ultimately determined
which operation to reschedule
because Coronet could not be moved back without moving it closer to the monsoon season and
thus risking serious restrictions on the ground campaign from flooded fields, and the air
campaign from cloud cover that almost doubles from early March to early April.& This
was a no-brainer.& MacArthur proposed bumping the Kyushu invasion ahead by a month.
& As soon as this was pointed out, both Nimitz and the Joint Chiefs in Washington
immediately agreed.& Olympic was moved forward one month to November 1, which also
gave the Japanese less time to dig in.
Unfortunately these best-laid plans would not have unfolded as expected even if the atom
bombs had not been dropped and the Soviet entry into the Pacific War had not frustrated
Tokyo's last hope of reaching a settlement short of unconditional surrender- a
Versailles-like outcome unacceptable to Truman and many of his contemporaries because it
was seen as an incomplete victory that could well require the next generation to refight
the war.& An infinitely bigger war than the late unpleasantness in Vietnam, which
would have seen us sending troops overseas in 1965 to fight Japan instead of to Southeast
Asia.& No deferments for that one.& [Laughter.]& The end result of this
delay would have been an even more costly campaign on Honshu than was predicted.& A
blood bath in which pre-invasion casualty estimates rapidly became meaningless because of
something that the defenders could not achieve on their own, but a low pressure trough
sitting along the Asian littoral would:& knock the delicate US timetable off balance.
The Divine Wind, or Kamikaze, of a powerful typhoon destroyed a foreign invasion force
heading for Japan in 1281, and it was for this storm that Japanese suicide aircraft of
World War II were named.& On October 9, 1945, a similar typhoon packing 140-mile per
hour winds struck the American staging area on Okinawa that would have been expanded to
capacity by that time if the war had not ended in September, and was still crammed with
aircraft and assault shipping- much of which was destroyed.& US analysts at the scene
matter-of-factly reported that the storm would have caused up to a 45-day delay in the
& invasion of Kyushu.& The point that goes begging, however, is that while these
reports from the Pacific were correct in themselves, they did not make note of the
critical significance that such a delay, well past the initial- and unacceptable-
target date of December 1, would have on base construction on Kyushu, and consequently
mean for the Honshu invasion, which would have then been pushed back as far as mid-April
If there had been no atom bombs and Tokyo had attempted to hold out for an extended time-
a possibility that even bombing and blockade advocates granted- the Japanese would have
immediately appreciated the impact of the storm in the waters around Okinawa.
& Moreover, they would know exactly what it meant for the follow-up invasion
of Honshu, which they had predicted as accurately as the invasion of Kyushu.& Even
with the storm delay and friction of combat on Kyushu, the Coronet schedule would have led
US engineers to perform virtual miracles to make up for lost time and implement Y-Day as
early in April as possible.& Unfortunately the Divine Winds packed a one-two punch.
On 4 April 1946, another typhoon raged in the Pacific, this one striking the northernmost
Philippine island of Luzon on the following day where it inflicted only moderate damage
before moving toward Taiwan.& Coming almost a year after the war, it was of no
particular concern.& The Los Angeles Times gave it about a paragraph on the
bottom of page 2.& But if Japan had held out, this storm would have had profound
effects on the world we live in today.& It would have been the closest watched
weather cell in history.& Would the storm move to the west after hitting Luzon, the
Army's main staging area for Coronet, or would it take the normal spiraling turn to the
north, and then northeast as the October typhoon?& Would slow, shallow-draft landing
craft be caught at sea or in the Philippines where loading operations would be put on
hold?& If they were already on their way to Japan, would they be able to reach
Kyushu's sheltered bay?& And what about the breakwater caissons for the massive
artificial harbor to be assembled near Tokyo?& The construction of the harbor's
pre-fabricated components carried a priority second only to the atom bomb, and
this precious towed cargo could not be allowed to fall victim to the storm and be
scattered across the sea.&&&
Whatever stage of employment US forces were in during those first days of April, a delay
of some sort- certainly no less than a week and perhaps much, much more- was
going to occur.& A delay that the two US field armies invading Honshu, the First and
Eighth, could ill afford and that Japanese militarists would see as yet another sign that
they were right after all. This is critical.& Various authors have
noted that much of the land today contains built-up areas not there in 1946, but are
blissfully unaware that, thanks to the delays, anyone treading this same, quote:
&flat, dry tank country& in 1946 would, in reality, have been up to their calves
in muck and rice shoots by the time the invasion actually took place.
Recent years have also seen the claim that the kamikaze threat was overrated.& Time
does not allow the subject to be discussed in any sort of detail here, but one aspect is
worth emphasizing:& US intelligence turned out to be dead wrong about the number of
Japanese planes available to defend the Home Islands.& Estimates that 6,700 could be
made available in stages, grew to only 7,200 by the time of the surrender.& This
number, however, turned out to be short by some 3,300 in light of the armada of 10,500
planes which the enemy planned to expend in stages during the opening phases of the
invasion operations- most as Kamikazes.& All guesswork aside, occupation authorities
after the war found that the number of military aircraft actually available in the Home
Islands was over 12,700.& Another thing about those 3,300 undetected aircraft, it is
worthwhile remembering that, excluding aircraft that returned to base, the Japanese
actually expended well under half that number as Kamikazes at Okinawa, roughly 1,400,
where over 5,000 US sailors were killed.
Of course, to some, all this discussion about the surprise 3,300 kamikaze aircraft, the
delay of the Honshu landing until the rice paddies were flooded, etc., is all moot because
the Japanese were supposedly just itching to surrender even before the dropping of the
atom bombs and the Soviet Union's entry into the war.& Well, we'll just have to save
that one for another time.& [NOTE:& For more on this side of the coin see Sadao
Asada's article in the Fall 1998 Pacific Historical Review as well as the Herbert
Bix piece in the Spring 1995 Diplomatic History.]& Thank you all for
allowing me to address you today.& I'll conclude with a quick run-through of some
slides to illustrate the tactical and strategic situation.
Slide 1-& Operation's Olympic and Coronet.& On the US side: 43 division
equivalents.& At the time of the surrender, the divisions within the dashed lines
were in various stages of transferring from French ports to the Philippines.& There
were also approximately six more that were to be made available, three from Europe and
three from the Pacific, with additional reserves in the continental United States.
& Great Britain would have supplied a minimum of three more divisions.& Separate
engineer, logistic and Army Air Force personnel would initially number in the hundreds of
thousands and eventually surpass a million men.
Slide 2-& Close-up of the Olympic invasion area on Kyushu.& Divisions conducting
initial assault.& Follow-on divisions.& Two Japanese corps.& No intent to
take entire island with its multi-million civilian population. Advance to a stop line far
enough from the developing anchorage and airbase construction to keep them out of
artillery range.
Slide 3-& The provisional layout of the fighter defense of the Olympic invasion area.
& Radar pickets.& Unlike Okinawa and the Marianas Turkey Shoot, where the great
distances forced Japanese aircraft to approach along relatively narrow and predictable
corridors, here the close proximity to bases would allow them to approach the highly
vulnerable transports from anywhere along a wide arc.&& Mountain passes.
& The most dangerous scenario envisioned the Japanese slipping aircraft through the
mountain passes and below the thin screen of combat air patrols- which, incidentally, is
one of the things the Japanese planned to do.
Slide 4-& Coastal terrain typical of southern Kyushu.& This obviously would not
be selected as a landing beach but even the ones selected had cliffs like these which were
being heavily fortified.
Slide 5-& This is a Japanese illustration of one of the earlier coastal artillery
positions built into the cliffs much like these at the British fortress at Gibraltar.
& Later portals were left rough, both to conserve concrete and lessen their
visibility.& Tunnels were also angled to give better protection from the direct fire
of naval guns.
Slide 6-& Highly defensible terraced rice fields were a common feature on areas that
could not be bypassed on both Kyushu and Honshu.
Slide 7-& The underground stockpiling of munitions, gasoline and other war supplies
was well advanced at the time of the surrender, roughly four months before the opening
invasion, and perhaps as much as eight long months before the assault on Honshu.
& There is never enough time to prepare for an invasion, but from a purely technical
standpoint, eight months is practically an eternity.& American planners worked from
the assumption that the war could last into at least the end of 1946.& The Emperor
was also not planning to go down fighting in the ruins of Tokyo as Hitler had in Berlin,
and a massive staging area and underground complex beyond the Kanto Mountains was well on
the way to completion when the war ended.& It was located about a hundred miles
northwest of Tokyo near the Olympic site at Nagano.
Slide 8-& A Japanese poster warning the population that attacks on the Home Islands
will intensify.& It reads:& Should there be air raids,& They will not
be intended for destroying our Homeland, But will be aimed to strike at our morale,
& Are we to let them destroy our Yamato fighting spirit?
Slide 9-& Japanese midget submarines at Kure naval base.& Reading the Summary
Report of the huge US Strategic Bombing Survey one gets the impression that Japanese
industry was kaput.& However, the highly political document was written to advance
the objectives of air power advocates and presented a somewhat rosy picture of what the
Army Air Force had accomplished.& As this photo demonstrates, not only could highly
technical priority items still be produced in quantity, they could also be successfully
hidden from the prying eyes of US reconnaissance aircraft fully six months after
they commenced operations from nearby Okinawa.
Slide 10-& The operational plan for Operation Coronet called for a swift strike up
the Kanto Plain to cut off Tokyo by a pair of US armored divisions from Europe.& As a
practical matter, however, there was no way to actually conduct the envisioned movement in
a timely fashion.&&
Slide 11-& The brown area on these maps indicated areas of seasonal flooding in
the plain.& Gray indicates areas that can be artificially flooded, while blue
indicates land containing high densities of rice paddies.& Moreover, [back to slide
10] as US mechanized forces moved north along the highway between the low-lying areas and
the foothills, more and more of their left
flank would be exposed to artillery in these foothills.& To get at this artillery,
additional divisions would have to be pushed into the ever-lengthening hill mass to
conduct fighting similar to that of Italy two years earlier and Korea five years in the
future.& As of August 1945 this had not yet been anticipated, consequently no
significant amount of troops had been allocated to this critical and manpower-intensive
Slide 12-& Even when rice paddies are ostensibly dry as this one is, they present
formidable barriers to even tracked movement.& Moreover, the sodden nature
of most dikes and paddy floors did not lend themselves to effective operation of devises
like the hedgerow cutters in Normandy.& The rice paddies would have to be taken in a
tedious, set-piece manner.
Meanwhile, the armored divisions fighting up the main road north past Tokyo would
frequently find themselves limited to a one-tank front as happened to British XXX Corps
when it was delayed reaching Arnhem by minimal German forces in the Dutch
Slide 13-& Many are familiar with the various personal anti-tank weapons Japanese
infantry were to employ, like hollow-charge rifle grenades plus the usually suicidal
satchel charges and plethora of hand-operated hollow-charge mines.& However, the
///real/// killer of US tanks during the invasion- especially on the Kanto Plain- was
going to be a weapon that the Japanese had been unable to put to good use so far in the
war:& the Mark 97 20mm rapid-fire anti-tank rifle.& Even the comparatively thin
frontal armor of the M4 Sherman was too thick for such a weapon, but in the paddy fields
it was a different story.& At short range from expertly camouflaged positions, even a
mediocre gunner could pump from two to a half dozen shots into the 1-inch and less belly
armor of the Sherman as they reared up high over the dikes.& Passing beneath the
driver and bow machine-gunner, the shells would smash into turret personnel, engine
compartment and stored ammunition with catastrophic results.& Japanese divisions were
initially issued only 18 of these weapons each.& After Saipan, the 20mm was
manufactured in such great quantities that even the newest units contained the revised
complement of 8 per rifle company- that's 72 per division.
Slide 14-& Last is a photo of the Sugar Loaf on Okinawa a relatively unimposing
little hill with a total area of not much more than two football fields.& Note the
size of the two soldiers at the summit.& Putting aside the artillery-studded
foothills along the Eighth Army's steadily lengthening flank, and the ongoing slugfest
along the elevated roads and rice paddies, it is useful to note& that there were many
such unimposing terrain features on the Kanto Plain that, like this little Okinawan hill,
could not be easily bypassed.& In five days of fighting in May 1945, the Japanese
defenders here and on two supporting hills behind it inflicted over 3,000 Marine
casualties- in spite of lavish tank and artillery support- before they were finally
Slide 15-& Two Down- One to Go.&& [Cover of War Department pamphlet
distributed to troops in summer 1945.]
Published by D. M. Giangreco on this subject from about 1995 to date:
&Casualty Projections for the U.S. Invasions of Japan: Planning and Policy
Implications& Journal of Military History (July 1997): 521-81
&To Bomb or Not to Bomb,& Naval War College Review (Spring 1898):
&Truman and the Hiroshima Cult& and othe books reviewed, Naval History,
Naval Institute (October 1995): 54-55
&Operation Downfall: US Plans and Japanese Countermeasures,& at the
University of Kansas symposium Beyond Bushido: Recent Work in Japanese
Military History, February 16, 1998
&Dropping the bomb on Japan: a-COUNT-ing for the Casualties& on the NET
television program Modern War, Washington, DC, December 12, 1997
&Operation Downfall:& The Devil Was In the Details,& Joint Force
Quarterly,
National Defense University (Autumn 1996): 86-94.
Chaired panel at the 1999 SMH conference at Penn State, What Did They Know
and When Did They Know It?:& Intelligence Assessments and Assumptions Before
the Invasion of Japan.& Papers available in booklet form in June:& Robert H.
Ferrell (Indiana State), Jacob W. Kipp (US Army Command and General Staff
College), General Makhmut Akhmetevich Gareev (Academy of Military Science,
Moscow) and Thomas B. Allen (National Geographic).
Letter, Journal of American History (June 1997): 322-23
Letter, Joint Force Quarterly (Summer 1996): 6-7
Letter, New England Quarterly (September 1998): 481-83.
Engaged in a general discussion of Robert P. Newman's work in the the
April 1998 American Historical Review, 663-64, and a book review
(Alperovitz et al) coming up in Parameters, US Army War College.& Subject
also comes up in newest book Dear Harry: The Truman Administration
through Correspondence with &Everyday Americans& ().