The American forces had conquered the island of Okinawa at a tremendous cost.
Germany had surrendered, but the fight was not over yet in the Pacific.
The Army, Navy, and Marines still had a job to do: the invasion of mainland Japan.
Rumors were quickly spreading.
Some said the Japanese were training over 30 million civilians for a fight to their
last breath.
Others speculated the Imperial Navy was preparing more than 100,000 troops for suicide attacks
aboard aircraft, ships, boats, submarines, and even underwater frogmen operations.
However, the Marines and Army soldiers felt most puzzled about the fact that the military
had already made over 500,000 Purple Heart medals for the wounded in combat and tens
of thousands of crosses and stars of David for those who would not return.
Unfortunately, these last rumors would prove to be true.
The US military was preparing for Operation Downfall, the largest in military history:
the occupation of Japan at any cost.
Pacific Inferno
The United States military began devising plans for a possible war against the Empire
of Japan in the early 20th century.
Such was the case of War Plan Orange, a series of projects by the Army and Navy to protect
US interests in the Pacific and stop Japanese expansion.
Fleet Admiral Ernest J. King and other Navy officers deduced that invading the Japanese
Home Islands was folly because it would lead to disproportionate casualties the American
populace would never tolerate.
The Army believed public support would remain on their side if the invasion was swift.
By the time World War 2 broke out, the Joint Chiefs of Staff realized war with Japan would
not be as straightforward as the plans envisioned.
In the aftermath of the Battle of Midway in June 1942, American forces commenced their
island-hopping campaigns, forcing the Japanese to adopt a defensive strategy.
Island by island, the US forces pushed the Imperial Army and Navy back to mainland Japan.
Japanese resistance stiffened as the Marines, Army, and Navy advanced deeper into Asia,
leading to more casualties for both sides.
These numbers rose in battles such as Peleliu, Iwo Jima, and especially Okinawa, where over
8,000 US servicemen lost their lives, and the Japanese garrison was practically obliterated
alongside the native population.
The Empire was committed to fighting to the last man, despite the mounting casualties
and the endless American bombing raids that broke the Japanese economy, leaving the country
in flames.
Nevertheless, they were prepared for what was coming.
Downfall
Japan’s situation was more than desperate.
Of its more than four million soldiers, half were trapped in China and Manchuria.
In addition, the Imperial Navy was severely depleted.
Still, the population was committed to its Emperor, which meant loyalty until the end.
US war planners also faced difficulties.
While preparing for the invasion of Japan, they looked back into history.
They realized the Japanese had never surrendered to a foreign power in over 2,600 years of
history.
More importantly, Japan had never been successfully invaded.
With no surrender in sight, the Joint Chiefs of Staff merged two ideas from the Navy and
the Army.
From June until November 1945, the Navy would continue bombing Japan by air and sea.
After November, the Army and Marines would join the fray with a two-phase invasion of
Japan under Operation Downfall.
The first phase, codenamed Operation Olympic, aimed to capture the southern portion of Kyushu.
The second phase, codenamed Operation Coronet, comprised the capture of Tokyo and was expected
to be launched in March 1946.
However, In late June 1945, President Harry S. Truman reviewed Operation Downfall and
only approved Operation Olympic, knowing logistics and casualties were bound to be a problem.
Olympic
Kyushu is the southernmost of the four main islands that comprise Japan.
It extends some 200 miles from north to south and has a width of 80 to 120 miles from west
to east.
More than half of its territory consists of mountainous terrain.
Plainlands are few and scattered along the island´s coasts, complicating American operations.
The US objective for Operation Olympic was to secure the southern part of the island,
from Tsuno, on the east coast, to Sendai, on the west.
This area would provide space for the construction of four air bases that would become critical
for the bombing and air support operations of the second phase.
The Kyushu landings would begin on November 1 with one of the heaviest neutralization
bombardments of the Pacific Theatre.
Air and naval barrages would pound Kyushu and the rest of Japan without remorse.
General MacArthur employed 14 divisions of Army and Marines to secure several beachheads
and advance inland to establish the defensive perimeter.
The Sixth Army expected over 125,000 combat casualties and more than 270,000 non-battle
casualties for the capture of Kyushu.
The Joint Chiefs of Staff were less optimistic and forecasted over 500,000 US casualties.
In late July 1945, the Department of Defense estimated 1.7 to four million American losses
for the Downfall operations.
The Japanese fared no better.
The DOD estimated between five to 10 million Japanese losses without considering the wounded.
Still, preparations for the second phase continued.
Mounting Losses
The second phase of the invasion of Japan, Operation Coronet, was expected to begin four
months after the landings at Kyushu.
Almost two million men and 40 divisions were contemplated for the operation.
This time, the US would receive direct support from the United Kingdom and Commonwealth forces.
In addition to the ground troops, more than 20 fast aircraft carriers with 2,000 aircraft,
30 cruisers, 107 destroyers, and 11 battleships from the Third Fleet would provide air and
naval support to the landing forces.
The Sixth Fleet under Admiral Raymond Spruance comprised an additional 2,900 ships that would
put ashore over 582,000 troops from the Sixth Army.
The Fifth Fleet would provide naval support with 800 combat ships, 1,500 transport vessels,
24 cruisers, 140 destroyers, and more than 160 destroyer escorts.
The initial landings would be carried out by three marine divisions, two armored divisions,
and ten reinforced infantry divisions.
Overall, 25 divisions would be tasked with seizing the Kanto Plain, Tokyo, and Yokohama.
Additional divisions, including an airborne division, would be available as the campaign
progressed.
Air and naval support would pound mainland Japan and the territories in China and Manchuria
occupied by the Japanese forces.
British, Austrian, Canadian, and French divisions were contemplated to participate during the
last stages of the campaign.
While the United States amassed the forces available in the Pacific, rumors from Downfall
were obtained by Japanese intelligence, leading to preparations to counter the US landings
scheduled for Olympic.
All Hands On Deck
Japanese Intelligence correctly estimated that the US forces' main objective would be
southern Kyushu to secure air bases and anchorage for US Navy vessels.
The southern portion of the island was within the maximum range of American aircraft from
Okinawa, leading the Japanese to assess the enemy would only attempt to seize that part
of Kyushu.
They also correctly assessed the main landings' targets, the expected date of the operation,
and the possible number of enemy divisions destined for Operation Olympic.
The Japanese then launched Operation Ketsugo, or Decisive Operation, to reinforce the four
islands from the upcoming invasions.
Kyushu was quickly reinforced with 15 divisions, numbering 680,000 defenders, matching the
number of attacking American forces.
A Japanese directive assessed the only way to break American support for the invasion
was to inflict massive casualties.
Consequently, the objective of Ketsugo was not to hold Japanese territory but to take
the lives of as many Americans as possible at whatever cost to break the will of the
American people.
The Empire had over four million troops, but half were stationed overseas.
Only 1.2 million soldiers could be adequately equipped for combat and count with the appropriate
ammunition supply.
Japan sought to prepare for combat with over 31 million people through conscription.
From teenagers to senior citizens, men and children were expected to sacrifice themselves
for the Emperor armed with swords, knives, bamboo spears, and other rudimentary weaponry.
Outcome
A Japanese propaganda slogan from the summer of 1945 echoed the national spirit.
It said: (QUOTE) “The sooner the Americans come, the better…
One hundred million die proudly.”
38 out of 46 submarines would be the first thing US troops faced when entering Kyushu.
Troop transports were the priority.
Between 120 and 900 Kaiten manned torpedoes would wreak havoc in the crowded waters of
Kyushu with the support of more than 1,000 midget submarines.
Once the Americans crowded the beachheads, the Imperial Navy would commit its fleet's
last 19 operational destroyers for one-way attacks on amphibious ships.
3,300 Shinyo boats armed with a 550-pound explosive charge in the bow would ensure massive
casualty numbers.
Additionally, the Imperial Navy planned to employ 4,000 frogmen, or Fukuryu, carrying
explosives to swim to the landing craft and blow themselves up.
The Imperial Army and Navy had amassed their 12,000 surviving aircraft for continuous kamikaze
attacks that would be launched in hourly waves of 300 to 400 fighters to saturate the US
Navy defenses.
Ultimately, Operation Downfall and its costly toll on the Japanese and American forces never
came to be.
President Truman avoided the bloodshed and warned Joseph Stalin of his expansionist desires
by dropping the two atomic bombs, a decision debated to this day.
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