... Operation Olympic, planned for October-November, 1945, was to be the first of a 2-part seaborne invasion of the Japanese Home Islands, with a 14 Division assault, some 300,000 land-combat troops and approximately 4 to 5 times that number of Naval, Airforce, and non-combatant support personnel, on the Southernmost Home Island, Kyushu. The second phase, named Operation Coronet, was to commence on or about March 1, 1946, providing Olympic had gone at least marginally according to plan, something that was by no means a foregone conclusion. The the Coronet assault was to be a 25 Division assault on the Main Home Island, Honshu, the immediate objective being a drive up the Tokyo Plain, both to take the capital and to bifurcate the defender's troop concentration. All told, between the two operations, an initial allocation of some 1.8 Million combat troops and over 3 Million other military, were to be committed, or nearly one half of all US uniformed forces at the time, would be involved in the operations, along with civilian support, mostly Merchant Marine, numbering into the low hundreds of thousands. Total manpower commitment to the invasion was to be well upwards of 5 Million souls; the entirety of The US Marine Corps, the entire US Pacific Fleet (some 3000 ships), the entire 8th Army, the entire 8th Air Force (redeployed from Europe), the entire 20th Airforce, and the entire American Far Eastern Air Force and roughly one third of The Merchant Marine.
Heavy casualties were expected, given experience gained from the nearly three years of island hopping begun at Guadalcanal in November of 1942. Estimates for the Kyushu assault alone were 2 to 3 hundred thousand. General Douglas MacArthur, overall US Pacific Commander, officially anticipated over 1 Million Own Forces would be killed or wounded by the Autum of 1946. General Charles Willoughby, Mac Arthur's Intelligence Chief, considered that a conservative estimate.
Though effectively contained by a nearly impenetrable naval blockade, and daily pummeled from the air by endless streams of bombers, Japan adamantly refused surrender. A blockade isolates a Power, but it does not kill it. Strategic bombing lays waste to cities, devastates populations, crippling industry and transport, but leaves entire Armies relatively unscathed.
Truman approved the invasion plans on July 24, 1945, while at the Potsdam Conference. 2 days later, the UN issued the Potsdam Proclamation, a final call for Japan immediately to surrender, unconditionally, or face sure and total destruction. On the 29th of July, The Japanese Governmental News Agency, the official organ of the regime, formally broadcast to the world Japan's unswerving intention to refuse surrender and to ignore all provisos of the Potsdam Proclamation.
At about this time, late July of 1945, intelligence intercepts revealed Japan had closed all schools, non-essential industry, and commerce, mobilizing and arming much of its civilian population. Aerial reconnaissance clearly showed massive fortification and underground facility construction underway throughout Japan.
It was anticipated the initial action against Kyushu would commence on 27 October 1945, with the first moves of a 4-pronged attack to be the taking and occupation of of several smaller islands South and Southwest of Kyushu proper. The 40th Infantry Division and the 158th Regimental Combat Team were assigned this task, with Naval support from 3 Battleships, 12 Cruisers, and 4 Aircraft Carriers, along with myriad lesser warships. The islands were to provide land-based communications and radar, both to warn the fleet of enemy air or surface activity, and air traffic control for the air armada accompanying the invasion, as well as emergency aircraft landing facilities and a sheltered anchorage for damaged invasion vessels.
Bombardment, both by surface ship and by aircraft, would precede the beach landing by 72 hours, and continue throughout the operation, "rolling" in front of the planned overland advance. The main invasion of Kyushu was to commence at dawn November 1, with simultaneous amphibious assaults along the Eastern, Northern, and Western coasts of the island.
The 25th, 33rd, and 41st Infantry Divisions would have the Eastern prong, landing near the city of Myasaki, at 6 beach heads codenamed "Austin", "Buick", "Cadillac", "Chevrolet", "Chrysler" and "Cord". The assault objectives were to be the capture of the city and of a nearby large military airfield.
On the Southern Flank, the 1st Cavalry Division, the 43 Division, and the Americal Division would invade the Amake Bay area at beaches codenamed "DeSoto", "Dusenberg", "Essex", "Ford" and "Franklin". The objectives were the capture of the port cities of Shibshi and Kanoya, and another large Imperial Army Airfield.
To the West, the beaches were codenamed "Pontiac", "Reo", "Rolls Royce", "Saxon", "Star", "Studebaker", "Stutz", "Winton" and "Zephyr". V Amphibious Corps, consisting of 2nd, 3rd and 5th Marine Divisions was to take the port city of Kagoshima and to drive inland to the city of Sendai, site of a major Imperial Army Base.
On November 4th, following a feint attack on the island of Shikoku, 81st and 98th Infantry Divisions and the 11th Airborne Division, unless already committed elsewhere as emergency reserve, would attack Kagoshima Bay, across beaches codenamed "Locomobile", "Lincoln", "LaSalle", "Hupmobile", "Moon", "Mercedes", "Maxwell", "Overland", "Oldsmobile", "Packard" and "Plymouth", with the city of Kaimondake, a Naval Airfield, and a Submarine base as objectives.
A 4-month timetable was established for Olympic, and each month would see the landing of an additional 3 Divisions. The assault on Kyushu, itself the largest single military endeavor in to that time in history, was to be but prelude. Assuming success for Olympic, Coronet, the Main Event and over twice the size of its predecessor, was scheduled to open March 1st, 1946.
East of Tokyo, the American 1st Army would land the 5th, 7th, 27th, 44th, 86th and 96th Infantry Divisions, along with 1st, 4th and 6th Marine Divisions. To the South, at Sagami Bay, 8th and 10th Armies, comprised of the 4th, 6th, 8th, 24th, 31st, 32nd, 37th, 38th and 87th Infantry Divisions, accompanied by the 13th and 20th Armoured Divisions would strike inland toward the city complex of Yokohama. Subsequent assaults were to be conducted at various points by an additional 8 Divisions, the 2nd, 28th, 35th, 91st, 95th, 97th and 104th Infantry Divisions and the 11th Airborne Division. Follow-on forces, consisting of as many as an additional dozen Divisions redeployed from Europe and currently undergoing refitting, replacement, and retraining in the US already had their re-deployment orders.
This almost unimaginable force structure was calculated as necessary and sufficient roaccomplishe the task given the best estimates of the intelligence services at the time. Postwar examination of documents, discovery ofassetss, and interrogation of captured Senior Officers revealed the available intelligence had badly underestimated the actual defensive capacity of Japan.
Following the Okinawa campaign, during which Kamikaze attacks sunk 32 ships and damaged over 400 more, the assessment was that Japan had largely spent her airpower. The assumption was aided by the fact US bombers and fighters faced essentially no Japanese air interdiction over The Home Islands, and were able to roam and strike almost at will, day or night, hindered only by desultory anti-aircraft fire.
In fact, the Japanese Homeland Defense Plan, codenamed Ketsu-Go, had seen to the marshalling of over 12,700 serviceable aircraft, along with the construction of dozens ofsubterraneann hangar facilities, scores of hidden,camouflagedd airstrips, and the stockpiling of tens of thousands of gallons of fuel and hundreds of thousand tons ofmunitionss, from bombs and torpedoes to rockets, mortar rounds, and artillery projectiles, and a few thousand tons of military-grade explosives not encompassed with projectiles. Additionally, in "cottage shops" and under bridges, in basements and in mines and tunnels, military production was continuing at a feverish pace.
The Ketsu-Go plan was for four separate aerial campaigns against the invasion fleet. While 2000 fighters were to contest the skies over Kyushu, an initial 800 plane Kamikaze attack was to engage the fleet during its assembly about the islands, over Kyushu. A second force of over 300 planes was to target specifically the aircraft carriers and other ground-fire-capable ships, attacking in waves from all points of the compass. Over 800 more suicide planes were to target the transports and landing ships.
The Kyushu defense was allotted approximately 2000 additional planes, most of which which were to be used in suicide waves of from 50 to over 100, as the situation merited and circumstances permitted.
The Japanese calculated they could stymie the invasion and inflict crippling losses on both the capital ships and escorts and the support ships. Relying not just on air power, they had 40 operational submarines, each fully manned, fueled, and armed. Some 20 destroyers and three cruisers remained operational as well, and were to be used variously to counterattack the invasion fleet and, beached, as fire support platforms.
Additionally, there was a force of some 400 suicide submarines ... little more than manned torpedoes, but deadly nonetheless. The invasion fleet would come under devastating, unceasing assault from land, sea, and air, before the troops even got to the beaches.
Confident of inflicting staggering losses, though at horrendous cost to themselves, the Japanese anticipated the Americans would falter, back off, abandon the endeavor, and, shocked and demoralized, perhaps to offer at least face-saving, less-than-unconditional surrender terms.
Nothing if not meticulous in planning, the Japanese had a fallback plan, should the invasion succeed in lodging troops ashore, as they thought likely.
The most determined and fanatical defense of the war had been prepared. The Japanese High Command had correctly worked out not only when, but almost to the foot where the Americans would attack. They planned an experience very different from that which the island-hopping war had led the Americans to expect. To that point throughout the Pacific War, the Americans invariably had outnumbered their island-defendingadversariess by margins of 2-or-3-to-1.
On Kyushu, the odds would be less favorable to the Americans. Considerably less favorable; facing the anticipated 14 American Divisions would be 14 Japanese Divisions, 7 independent combined-arms forces of roughly Brigade strength, 3 fully equipped Tank Brigades, and several thousand Naval Troops. Around 800,000 defenders stood ready torepell some 500,000 invaders, assuming even that many had survived the furious pre-invasion defense. And unlike so often in the island campaigns, the defending troopswouldlwouldd not be ill-equipped, poorly trained labor and punishment battalions. The Home Army was well fed, well led, well trained, and well equipped. The remaining cream of the Army, tens of thousands of battle-tested veterans, elite troops in every sense, stiffened the lesser formations, which were themselves of a calibre markedly higher than that to which The Americans had become accustomed to meeting. And these troops were flush with a fanatical, almost-beyond-religious determination to sell their lives as dearly as they could.
Offshore mines, scuba divers, manned torpedoes, cunningly crafted obstacles, and onshore mines in the thousands comprised the first belt of beach defenses. Behind these were laid out over hundreds of yards row upon row of trenches and revetments, pillboxes and bunkers, all designed to be as inconspicuous as possible, and to be resistant to naval bombardment and aerial attack, with interlocking fields of fire, multiply reinforcing one another and situated to rake the beaches with withering fire. Further back were emplaced artillery and mortars, again protected by construction specifically created to offermaximunn protection from bothbombss and shells. The troops to man these positions were garrisoned, with as much of their equipment as was practical deep underground, impervious even to the 1-ton projectiles fired by Battleships. They had been drilled to remain in the safety of their shelters undergroundd fortresses, really -untill the last moment, at which point, American troops swarming ashore, the bombardment lifted to strike deeper inland, they could assume their positions, lay their weapons, and engage the enemy at the tideline.
They had developed a transportation and communication system virtually undetectable from the air, and were adept at using it. There were massive caches of arms and munitions in hundreds of concealed locations. There were yet more intertwining trenches and tunnels, hidden bunkers, hundreds of heavy artillery pieces, some mounted on rail cars, rigged to shuttle in and out of deep tunnels with concealed entrances, mortars and machineguns secreted within houses, shops, and schools, tanks disguised under haystacks and rubbish piles, endless tangles of barbed wire, fire ditches ready to be flooded with flammable liquid and set alight, and there were literally millions of anti-personnel and anti-armor mines, many already laid in the vicinity of the anticipated invasion beaches, huge quantities ready to be deployed. There were chemical weapons too. Gases and biologics, tested against Chinese, Mongolian, and Korean adversaries, were available and situated with troops trained andexperiencedd in their deployment. The defenders knew the lay of the land, and they were going to be defending their own homes and families. It was for them literally a fight to death or victory with no alternative between.
And then there was the armed and mobilized citizenry ... literally millions of them. Possessed only of the most rudimentary training, and given the crudest of weapons ... suicide weapons in large part, they were no less determined to die for theirEmperorr, Homeland, heritage, and honor than were the uniformed forces. Some 28 Million strong, the National Volunteer Combat force was galvanized under theincessantlyy drummed mantra "A Hundred Million will die gladly for our Emperor and Homeland". Armed with rifles left over from the Russo-Japanese War of 4 decades earlier, with long, grenade-tipped "lunge sticks", molotov cocktails, crude black powder bombs and mortars, swords, spears, and bows, some even with nothing more than sharpened bamboo stakes, their task was to collect payment for Japanese soil by means of massed night suicide attacks, hit-and-run ambushes, and delaying and masking operations in support of uniformed forces.
Had the invasion occurred, the casualties would have been measured in the tens and scores of thousands weekly for months. A million American casualties indeed would have been an improbably fortunate low tally. Japanese casualties likely would have been all but immeasurable ... in the many Millions at the very least. Physical damage toinfrastructuree and environment would have been unimaginable; orders of magnitude beyond anything ever seen or even contemplated. A proud and ancient nation - its society and culture literally would all but have died.
But that never happened. A half dozen planes, only two of which were armed, on August 6 and again on August 9th, saved history from the awful burden of recounting that tale. Some 80,000 to 90,000 people died at Hiroshima, perhaps half that many at Nagasaki, according to official numbers accepted by both the US and Japanese governments, and by The United Nations. Residual deaths, due to injuries and radiation poisoning, push the toll a bit higher, but still most experts estimate the carnage at well under 200,000. A crime if you wish, but surely a lesser crime than a slaughter and devastation incalculably worse. Sometimes life hands you tough choices. For untold millions, the kinder, gentler choice was the bombing of Hiroshima and Nagasaki.
