Army Corps of Engineers
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An Invasion Not Found in the History Books
Brig Gen R. Clements USAF ret, 16,
Deep in the recesses of the National Archives in Washington,D.C.,
hidden for nearly four decades lie thousands of pages of yellowing and
dusty documents stamped "Top Secret". These documents, now declassified,
are the plans for Operation Downfall, the invasion of Japan during
World War II. Only a few Americans in 1945 were aware of the elaborate
plans that had been prepared for the Allied Invasion of the Japanese home
islands. Even fewer today are aware of the defenses the Japanese had prepared
to counter the invasion had it been launched. Operation Downfall was finalized
during the spring and summer of 1945. It called for two massive military
undertakings to be carried out in succession and aimed at the heart of
the Japanese Empire.
In the first invasion - code named Operation Olympic - American
combat troops would land on Japan by amphibious assault during the early
morning hours of November 1, 1945 - 50 years ago. Fourteen combat divisions
of soldiers and Marines would land on heavily fortified and defended Kyushu,
the southernmost of the Japanese home islands, after an unprecedented
naval and aerial bombardment.
Europe), 10th Air Force and the American Far Eastern
Air Force. More than 1.5 million combat soldiers, with 3 million more in
support or more than 40% of all servicemen still in uniform in 1945 - would
be directly involved in the two amphibious assaults. Casualties were expected
to be extremely heavy.
|The second invasion on March 1, 1946
- code named Operation Coronet - would send at least 22 divisions
against 1 million Japanese defenders on the main island of Honshu
and the Tokyo Plain. It's goal: the unconditional surrender of Japan.
With the exception of a part of the British Pacific Fleet, Operation
Downfall was to be a strictly American operation. It called for using
the entire Marine Corps, the entire Pacific Navy, elements of the
7th Army Air Force, the 8 Air Force (recently redeployed from
|Admiral William Leahy
estimated that there would be more than 250,000 Americans killed or
wounded on Kyushu alone. General Charles Willoughby, chief of intelligence
for General Douglas MacArthur, the Supreme Commander of the Southwest
Pacific, estimated American casualties would be one million men by
the fall of 1946. Willoughby's own intelligence staff considered this
to be a conservative estimate.
During the summer of 1945, America had little time to prepare for
such an endeavor, but top military leaders were in almost unanimous
agreement that an invasion was necessary.
While naval blockade and strategic bombing of Japan was considered
to be useful, General MacArthur, for instance, did not believe a blockade
would bring about an unconditional surrender. The advocates for invasion
agreed that while a naval blockade chokes, it does not kill; and though
strategic bombing might destroy cities, it leaves whole armies intact.
So on May 25, 1945, the Joint Chiefs of Staff, after extensive deliberation,
issued to General MacArthur, Admiral Chester Nimitz, and Army Air
Force General Henry Arnold, the top secret directive to proceed with
the invasion of Kyushu. The target date was after the typhoon season.
General Douglas MacArthur estimated American
casualties would be one million men by the fall of 1946
was to seize and control the southern one-third of that island and establish
naval and air bases, to tighten the naval blockade of the home islands,
to destroy units of the main Japanese army and to support the later invasion
of the Tokyo Plain.
Meeting at Potsdam
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President Truman approved the plans for the invasions
July 24. Two days later, the United Nations issued the Potsdam Proclamation,
which called upon Japan to surrender unconditionally or face total
destruction. Three days later, the Japanese governmental news agency
broadcast to the world that Japan would ignore the proclamation
and would refuse to surrender. During this sane period it was learned
-- via monitoring Japanese radio broadcasts -- that Japan had closed
all schools and mobilized its schoolchildren, was arming its civilian
population and was fortifying caves and building underground defenses.
Operation Olympic called for a four pronged assault on Kyushu. Its
The preliminary invasion would began October 27 when
the 40th Infantry Division would land on a series of small islands west
and southwest of Kyushu. At the same time, the 158th Regimental Combat
Team would invade and
hundreds of Navy fighters, dive bombers and . torpedo planes would hit targets
all over the island of Honshu. The 3,000 ship Fifth Fleet, under Admiral
Raymond Spruance, would carry the invasion troops
| occupy a small island 28 miles south of Kyushu. On
these islands, seaplane bases would be established and radar would
be set up to provide advance air warning for the invasion fleet, to
serve as fighter direction centers for the carrier-based aircraft
and to provide an emergency anchorage for the invasion fleet, should
things not go well on the day of the invasion. As the invasion grew
imminent, the massive firepower of the Navy - the Third and Fifth
Fleets -- would approach Japan. The Third Fleet, under Admiral William
"Bull" Halsey, with its big guns and naval aircraft, would
provide strategic support for the operation against Honshu and Hokkaido.
Halsey's fleet would be composed of battleships, heavy cruisers, destroyers,
dozens of support ships and three fast carrier task groups. From these
Admiral William "Bull" Halsey
Hellcat folding wings on carrier (Nat'l Archives)
|Several days before the invasion,
the battleships, heavy cruisers and destroyers would pour thousands
of tons of high explosives into the target areas. They would not cease
the bombardment until after the land forces had been launched. During
the early morning hours of November 1, the invasion would begin. Thousands
of soldiers and Marines would pour ashore on beaches all along the
eastern, southeastern, southern and western coasts of Kyushu. Waves
of Helldivers, Dauntless dive bombers, Avengers, Corsairs, and Hellcats
from 66 aircraft carriers would bomb, rocket and strafe enemy defenses,
gun emplacements and troop concentrations along the beaches.
The Eastern Assault Force consisting of the 25th,
33rd and 41st Infantry Divisions would land near Miyaski, at beaches called
Austin, Buick, Cadillac, Chevrolet, Chrysler, and Ford, and move inland
to attempt to capture the city and its nearby airfield. The Southern Assault
Force, consisting of the 1st Cavalry Division, the 43rd Division and Americal
Division would land inside Ariake Bay at beaches labeled DeSoto, Dusenberg,
Ease, Ford, and Franklin and attempt to capture Shibushi and the city
of Kanoya and its airfield.
On the western shore of Kyushu, at beaches Pontiac,
Reo, Rolls Royce, Saxon, Star, Studebaker, Stutz, Winston and Zephyr,
The V Amphibious Corps would land the 2nd, 3rd and 5th Marine Divisions,
sending half of its force inland to Sendai and the other half to the port
city of Kagoshima.
On November 4, the Reserve Force, consisting of the
81st and 98th Infantry Divisions and the 11th Airborne Division, after
feigning an attack of the island of Shikoku, would be landed -- if not
needed elsewhere -- near Kaimondake, near the southernmost tip of Kagoshima
Bay, at the beaches designated Locomobile, Lincoln, LaSalle, Hupmobile,
Moon, Mercedes, Maxwell, Overland, Oldsmobile, Packard and Plymouth.
Olympic was not just a plan for invasion, but
for conquest and occupation as well. It was expected to take four months
to achieve its objective, with the three fresh American divisions per
month to be landed in support of that operation if needed.
If all went well with Olympic, Coronet
would be launched March 1, 1946. Coronet would be twice the size
of Olympic, with as many as 28 divisions landing on Honshu.
All along the coast east of Tokyo, the American 1st
Army would land the 5th, 7th, 27th, 44th, 86th, and 96th Infantry Divisions
along with the 4th and 6th Marine Divisions.
At Sagami Bay, just south of Tokyo, the entire 8th
and 10th Armies would strike north and east to clear the long western
shore of Tokyo Bay and attempt to go as far as Yokohama. The assault troops
landing south of Tokyo would be the 4th, 6th, 8th, 24th, 31st, 37th, 38th
and 8th Infantry Divisions, along with the 13th and 20th Armored Divisions.
|Following the initial assault, eight
more divisions - the 2nd, 28th, 35th, 91st, 95th, 97th and 104th Infantry
Divisions and the 11th Airborne Division -- would be landed. If additional
troops were needed, as expected, other divisions redeployed from Europe
and undergoing training in the United States would be shipped to Japan
in what was hoped to be the final push.
Captured Japanese documents and post war interrogations
of Japanese military leaders disclose that information concerning the
number of Japanese planes available for the defense of the home islands
was dangerously in error.
During the sea battle at Okinawa alone, Japanese kamakaze
aircraft sank 32 Allied ships and damaged more than 400 others. But during
the summer of 1945, American top brass concluded that the Japanese had
spent their air force since American bombers and fighters daily flew unmolested
What the military leaders did not know was that by
the end of July the Japanese had been saving all aircraft, fuel, and pilots
in reserve, and had been feverishly building new planes for the decisive
battle for their homeland.
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As part of Ketsu-Go, the name for the plan to defend Japan -- the
Japanese were building 20 suicide takeoff strips in southern Kyushu
with underground hangars. They also had 35 camouflaged airfields
and nine seaplane bases.
On the night before the expected invasion, 50 Japanese seaplane
bombers, 100 former carrier aircraft and 50 land based army planes
were to be launched in a suicide attack on the fleet.
The Japanese had 58 more airfields in Korea, western Honshu and
Shikoku, which also were to be used for massive suicide attacks.
Allied intelligence had established that the Japanese had no more
than 2,500 aircraft of which they guessed 300 would be deployed
in suicide attacks.
hoped could be sustained for 10 days. The Navy
-- some armed with Long Lance torpedoes with a range of 20 miles -- when
the invasion fleet was 180 miles off Kyushu
In August 1945, however, unknown to Allied intelligence, the Japanese
still had 5, 651 army and 7,074 navy aircraft, for a total of 12,
725 planes of all types. Every village had some type of aircraft
manufacturing activity. Hidden in mines, railway tunnels, under
viaducts and in basements of department stores, work was being done
to construct new planes.
Additionally, the Japanese were building newer
and more effective models of the Okka, a rocket-propelled bomb much
like the German V-1, but flown by a suicide pilot.
When the invasion became imminent, Ketsu-Go
called for a fourfold aerial plan of attack to destroy up to 800
While Allied ships were approaching Japan, but still in the open
seas, an initial force of 2,000 army and navy fighters were to fight
to the death to control the skies over Kyushu. A second force of
330 navy combat pilots were to attack the main body of the task
force to keep it from using its fire support and air cover to protect
the troop carrying transports. While these two forces were engaged,
a third force of 825 suicide planes was to hit the American transports.
As the invasion convoys approached their anchorages, another 2,000
suicide planes were to be launched in waves of 200 to 300, to be
used in hour by hour attacks.
By mid-morning of the first day of the invasion,
most of the American land-based aircraft would be forced to return
to their bases, leaving the defense against the suicide planes to
the carrier pilots and the shipboard gunners.
Carrier pilots crippled by fatigue would have
to land time and time again to rearm and refuel. Guns would malfunction
from the heat of continuous firing and ammunition would become scarce.
Gun crews would be exhausted by nightfall, but still the waves of
kamikaze would continue. With the fleet hovering Japanese planned
to coordinate their air strikes with attacks from the 40 remaining
submarines from the Imperial off the beaches, all remaining Japanese
aircraft would be committed to nonstop suicide attacks, which the
The Imperial Navy had 23
destroyers and two cruisers which were operational. These ships were to
be used to counterattack the American invasion. A number of the destroyers
were to be beached at the last minute to be used as anti-invasion gun
Once offshore, the invasion
fleet would be forced to defend not only against the attacks from the
air, but would also be confronted with suicide attacks from sea. Japan
had established a suicide naval attack unit of midget submarines, human
torpedoes and exploding motorboats
The goal of the Japanese was to shatter the
invasion before the landing. The Japanese were convinced the Americans
would back off or become so demoralized that they would then accept
a less-than-unconditional surrender and a more honorable and face-saving
end for the Japanese.
But as horrible as the battle of Japan would
be off the beaches, it would be on Japanese soil that the American
forces would face the most rugged and fanatical defense encountered
during the war.
Throughout the island-hopping Pacific campaign, Allied
troops had always out numbered the Japanese by 2 to 1 and sometimes 3
to 1. In Japan it would be different. By virtue of a combination of cunning,
guesswork, and brilliant military reasoning, a number of Japan's top military
leaders were able to deduce, not only when, but where, the United States
would land its first invasion forces.
Facing the 14 American divisions landing at Kyushu
would be 14 Japanese divisions, 7 independent mixed brigades, 3 tank brigades
and thousands of naval troops. On Kyushu the odds would be 3 to 2 in favor
of the Japanese, with 790,000 enemy defenders against 550,000 Americans.
This time the bulk of the Japanese defenders would not be the poorly trained
and ill-equipped labor battalions that the Americans had faced in the
|The Japanese defenders would be the hard core of the
home army. These troops were well-fed and well equipped. They were
familiar with the terrain, had stockpiles of arms and ammunition,
and had developed an effective system of transportation and supply
almost invisible from the air. Many of these Japanese troops were
the elite of the army, and they were swollen with a fanatical fighting
Japan's network of beach defenses consisted of offshore
mines, thousands of suicide scuba divers attacking landing craft, and
mines planted on the beaches. Coming ashore, the American Eastern amphibious
assault forces at Miyazaki would face three Japanese divisions, and two
others poised for counterattack. Awaiting the Southeastern attack force
at Ariake Bay was an entire division and at least one mixed infantry brigade.
On the western shores of Kyushu, the Marines would
face the most brutal opposition. Along the invasion beaches would be the
three Japanese divisions , a tank brigade, a mixed infantry brigade and
an artillery command. Components of two divisions would also be poised
to launch counterattacks.
If not needed to reinforce the primary landing beaches,
the American Reserve Force would be landed at the base of Kagoshima Bay
November 4, where they would be confronted by two mixed infantry brigades,
parts of two infantry divisions and thousands of naval troops.
All along the invasion beaches, American troops would
face coastal batteries, anti-landing obstacles and a network of heavily
fortified pillboxes, bunkers, and underground fortresses. As Americans
waded ashore, they would face intense artillery and mortar fire as they
worked their way through concrete rubble and barbed-wire entanglements
arranged to funnel them into the muzzles of these Japanese guns.
charges strapped on their chests or backs would attempt to blow up American
tanks, artillery pieces and ammunition stores as they were unloaded ashore.
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(Image courtesy Wikopedia)
|On the beaches and beyond would be hundreds of Japanese
machine gun positions, beach mines, booby traps, trip-wire mines and
sniper units. Suicide units concealed in "spider holes"
would engage the troops as they passed nearby. In the heat of battle,
Japanese infiltration units would be sent to reap havoc in the American
lines by cutting phone and communication lines. Some of the Japanese
troops would be in American uniform, English-speaking Japanese officers
were assigned to break in on American radio traffic to call off artillery
fire, to order retreats and to further confuse troops. Other infiltration
Beyond the beaches were large artillery pieces situated
to bring down a curtain of fire on the beach. Some of these large guns
were mounted on railroad tracks running in and out of caves protected
by concrete and steel.
combat aimed at an underground, heavily fortified, non-retreating enemy.
|The battle for Japan would be won by what Simon Bolivar
Buckner, a lieutenant general in the Confederate army during the Civil
War, had called "Prairie Dog Warfare." This type of fighting
was almost unknown to the ground troops in Europe and the Mediterranean.
It was peculiar only to the soldiers and Marines who fought the Japanese
on islands all over the Pacific -- at Tarawa, Saipan, Iwo Jima and
Okinawa. Prairie Dog Warfare was a battle for yards, feet and sometimes
inches. It was brutal, deadly and dangerous form of
had become a part of the National Volunteer Combat Force. They were armed
with ancient rifles, lunge mines, satchel charges, Molotov cocktails and
one-shot black powder mortars. Others were armed with swords, long bows,
axes and bamboo spears. The civilian units were to be used in nighttime
attacks, hit and run maneuvers, delaying actions and massive suicide charges
at the weaker American positions.
cave found on Guam
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In the mountains behind the Japanese beaches were underground networks
of caves, bunkers, command posts and hospitals connected by miles
of tunnels with dozens of entrances and exits. Some of these complexes
could hold up to 1,000 troops.
In addition to the use of poison gas and bacteriological warfare
(which the Japanese had experimented with), Japan mobilized its
Had Olympic come about, the Japanese civilian population,
inflamed by a national slogan - "One Hundred Million Will Die
for the Emperor and Nation" - were prepared to fight to the
death. Twenty Eight Million Japanese
cave found on Iwo Jima
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cave found on Iwo Jima
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At the early stage of the invasion, 1,000 Japanese and American
soldiers would be dying every hour
The invasion of Japan never became a reality because on August
6, 1945, an atomic bomb was exploded over Hiroshima. Three days
later, a second bomb was dropped on Nagasaki. Within days the war
with Japan was at a close.
Had these bombs not been dropped and had the invasion
been launched as scheduled, combat casualties in Japan would have been
at a minimum of the tens of thousands. Every foot of Japanese soil would
have been paid for by Japanese and American lives.
One can only guess at how many civilians would have
committed suicide in their homes or in futile mass military attacks.
In retrospect, the 1 million American men who were
to be the casualties of the invasion, were instead lucky enough to survive
Intelligence studies and military estimates made 50
years ago, and not latter-day speculation, clearly indicate that the battle
for Japan might well have resulted in the biggest blood-bath in the history
of modern warfare.
Far worse would be what might have happened to Japan
as a nation and as a culture. When the invasion came, it would have come
after several months of fire bombing all of the remaining Japanese cities.
The cost in human life that resulted from the two
atomic blasts would be small in comparison to the total number of Japanese
lives that would have been lost by this aerial devastation.
||With American forces locked in combat in the south of
Japan, little could have prevented the Soviet Union from marching
into the northern half of the Japanese home islands. Japan today could
be divided much like Korea and Germany.
The world was spared the cost of Operation Downfall,
however, because Japan formally surrendered to the United States September
2, 1945, and World War II was over.
The aircraft carriers, cruisers and transport ships
scheduled to carry the invasion troops to Japan, ferried home American
troops in a gigantic operation called Magic Carpet.
In the fall of 1945, in the aftermath of the war,
few people concerned themselves with the invasion plans. Following the
surrender, the classified documents, maps, diagrams and appendices for
Operation Downfall were packed away in boxes and eventually stored
at the National Archives. These plans that called for the invasion of
Japan paint a vivid description of what might have been one of the most
horrible campaigns in the history of man. The fact that the story of the
invasion of Japan is locked up in the National Archives and is not told
in our history books is something for which all Americans can be thankful.
I had the distinct privilege of being assigned as
later commander of the 8090th PACUSA detach, 20th AAF, and one of the
personal pilots of then Brig General Fred Irving USMA 17 when he was commanding
general of Western Pacific Base Command. We had a brand new C-46F tail
number 8546. It was different from the rest of the C-46 line in that it
was equipped with Hamilton Hydromatic props whereas the others had Curtis
electrics. On one ofthe many flights we had 14 Generals and Admirals aboard
on an inspection trip to Saipan and Tinian. Notable aboard was General
Thomas C. Handy, who had signed the operational order to drop the atomic
bombs on Japan. President Truman's orders were verbal . He never signed
an order to drop the bombs. On this particular flight, about halfway from
Guam to Tinian, a full Colonel (General Handy's aide) came up forward
and told me that General Handy would like to come up and look around.
I told him, Hell yes, he can fly the airplane if he wants to, sir
about General Irving. He was one of the finest
gentleman I ever met. He was the oldest living graduate of West Point when
he passed on at 100+. He was one of three Generals who had the honor of
being both the Supe and Com of West Point. I think the other gentleman were
BG Sladen clliSS of 1890 and BG Stewart Class of 1896
|He came up and sat in the copilot's
seat, put on the headset and we started chatting. I asked him if he
ever regretted dropping the bombs. His answer was, Certainly not.
We saved a million lives on both sides by doing it. It was the right
thing to do I never forgot that trip and the honor of being able to
talk to General Handy. I was a Lt at the time. A postscript
"I asked him if he ever regretted dropping
the bombs. His answer was, Certainly not. We saved a million lives
on both sides by doing it."
I am very happy the invasion never came off because if it had I don't think
I would be writing this today. We were to provide air support for the boots
on the ground guys. The small arms fire would have been devastating and
lethal as hell to fly through .. Just think what it would have been like
on the ground .....
But, C'est !a vive. You do what needs to be done. You don't act like gutless
wonders and carry peace signs around ....
"Of course we celebrated (the bombing
if Hiroshima.) We were fully aware that our death sentence had been lifted."
Major General Will Simlik, USMC
Suggested by Tom Kercher and John Hopkins
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