Declassified Plans to Invade Japan WWII
Any history buff should read this. It is most informative, enlightening, and very interesting as well.
Here is some interesting history of why the A-Bomb was dropped on Japan.
Deep in the recesses of the National Archives in Washington, DC, hidden for nearly 4 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 WWII.
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 2 massive military undertakings to be carried out in succession & 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 – 61 years ago. Fourteen combat divisions of soldiers and Marines would land on heavily fortified & defended Kyushu, the southernmost of the Japanese home islands, after an unprecedented naval & aerial bombardment.
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 & the Tokyo Plain. Its 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 Europe), 10th Air Force & 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 2 amphibious assaults. Casualties were expected to be extremely heavy. 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, 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 & 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; & 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, & 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.
President Truman approved the plans for the invasions July 24. Two days later, the UN 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 & would refuse to surrender. During this same period it was learned — via monitoring Japanese radio broadcasts — that Japan had closed all schools & mobilized its school children, was arming its civilian population & was fortifying caves & building underground defenses.
Operation Olympic called for a 4-pronged assault on Kyushu. Its purpose was to seize and control the southern one-third of that island & establish naval & air bases, to tighten the naval blockade of the home islands, to destroy units of the main Japanese army & to support the later invasion of the Tokyo Plain.
The preliminary invasion would begin October 27 when the 40th Infantry Division would land on a series of small islands west & southwest of Kyushu. At the same time, the 158th Regimental Combat Team would invade & occupy a small island 28 miles south of Kyushu. On these islands, seaplane bases would be established & 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 & 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 & 3 fast carrier task groups. From these carriers, hundreds of Navy fighters, dive bombers & 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.
Several days before the invasion, the battleships, heavy cruisers & 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 & 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, & Hellcats from 66 aircraft carriers would bomb, rocket & strafe enemy defenses, gun emplacements & troop concentrations along the beaches.
The Eastern Assault Force consisting of the 25th, 33rd, & 41st Infantry Divisions, would land near Miyaski, at beaches called Austin, Buick, Cadillac, Chevrolet, Chrysler, & Ford, and move inland to attempt to capture the city & its nearby airfield. The Southern Assault Force, consisting of the 1st Cavalry Division, the 43rd Division & Americal Division would land inside Ariake Bay at beaches labeled DeSoto, Dusenberg, Essex, Ford, & Franklin & attempt to capture Shibushi & the city of Kanoya & its airfield.
On the western shore of Kyushu, at beaches Pontiac, Reo, Rolls Royce, Saxon, Star, Studebaker, Stutz, Winston & Zephyr, the V Amphibious Corps would land the 2nd, 3rd, & 5th Marine Divisions, sending half of its force inland to Sendai & the other half to the port city of Kagoshima. On November 4, the Reserve Force, consisting of the 81st & 98th Infantry Divisions & the 11th Airborne Division, after feigning an attack on 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, & Plymouth.
Olympic was not just a plan for invasion, but for conquest & occupation as well. It was expected to take 4 months to achieve its objective, with the 3 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 & 6th Marine Divisions. At Sagami Bay, just south of Tokyo, the entire 8th & 10th Armies would strike north & east to clear the long western shore of Tokyo Bay & attempt to go as far as Yokohama. The assault troops landing south of Tokyo would be the 4th, 6th, 24th, 31st, 37th, 38th, & 8th Infantry Divisions, along with the 13th & 20th Armored Divisions.
Following the initial assault, 8 more divisions – the 2nd, 28th, 35th, 91st, 95th, 97th, & 104th Infantry Divisions & the 11th Airborne Division — would be landed. If additional troops were needed, as expected, other divisions redeployed from Europe & undergoing training in the US would be shipped to Japan in what was hoped to be the final push.
Captured Japanese documents & 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 Kamikaze aircraft sank 32 Allied ships & 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 & fighters daily flew unmolested over Japan.
What the military leaders did not know was that by the end of July the Japanese had been saving all aircraft, fuel, & pilots in reserve, & had been feverishly building new planes for the decisive battle for their homeland.
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 & 9 seaplane bases.
On the night before the expected invasion, 50 Japanese seaplane bombers, 100 former carrier aircraft & 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 & 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. In August 1945, however, unknown to Allied intelligence, the Japanese still had 5,651 army & 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 & in basements of department stores, work was being done to construct new planes.
Additionally, the Japanese were building newer & 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 Allied ships.
While Allied ships were approaching Japan, but still in the open seas, an initial force of 2,000 army & navy fighters were to fight to the death to control the skies over Kyushu. A second force of 330 navy combat pilots was to attack the main body of the task force to keep it from using its fire support & air cover to protect the troop carrying transports. While these 2 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 & the shipboard gunners. Carrier pilots crippled by fatigue would have to land time & time again to re – arm & refuel. Guns would malfunction from the heat of continuous firing & ammunition would become scarce. Gun crews would be exhausted by nightfall, but still the waves of kamikaze would continue. With the fleet hovering off the beaches, all remaining Japanese aircraft would be committed to nonstop suicide attacks, which the Japanese hoped could be sustained for 10 days. The Japanese planned to coordinate their air strikes with attacks from the 40 remaining submarines from the Imperial Navy – some armed with Long Lance torpedoes with a range of 20 miles — when the invasion fleet was 180 miles off Kyushu.
The Imperial Navy had 23 destroyers & 2 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 platforms. 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 & 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 & a more honorable & 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 & fanatical defense encountered during the war.
Throughout the island-hopping Pacific campaign, Allied troops had always outnumbered 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, & brilliant military reasoning, a number of Japan’s top military leaders were able to deduce, not only when, but where, the US 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 & 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 earlier campaigns.
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 & ammunition, & 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, & they were swollen with a fanatical fighting spirit.
Japan’s network of beach defenses consisted of offshore mines, thousands of suicide scuba divers attacking landing craft, & mines planted on the beaches. Coming ashore, the American Eastern amphibious assault forces at Miyazaki would face 3 Japanese divisions, & 2 others poised for counterattack. Awaiting the Southeastern attack force at Ariake Bay was an entire division & at least 1 mixed infantry brigade.
On the western shores of Kyushu, the Marines would face the most brutal opposition. Along the invasion beaches would be the 3 Japanese divisions, a tank brigade, a mixed infantry brigade & an artillery command Components of 2 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 2 mixed infantry brigades, parts of 2 infantry divisions & thousands of naval troops.
All along the invasion beaches, American troops would face coastal batteries, anti-landing obstacles & a network of heavily fortified pillboxes, bunkers, & underground fortresses. As Americans waded ashore, they would face intense artillery and mortar fire as they worked their way through concrete rubble & barbed-wire entanglements arranged to funnel them into the muzzles of these Japanese guns. On the beaches & beyond would be hundreds of Japanese machine gun positions, beach mines, booby traps, trip-wire mines & 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 & 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 & to further confuse troops. Other infiltration with demolition charges strapped on their chests or backs would attempt to blow up American tanks, artillery pieces & ammunition stores as they were unloaded ashore.
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 & out of caves protected by concrete & steel. 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 & the Mediterranean. It was peculiar only to the soldiers & Marines who fought the Japanese on islands all over the Pacific — at Tarawa, Saipan, Iwo Jima & Okinawa. Prairie Dog Warfare was a battle for yards, feet & sometimes inches. It was brutal, deadly & dangerous form of combat aimed at an underground, heavily fortified, non-retreating enemy. In the mountains behind the Japanese beaches were underground networks of caves, bunkers, command posts & hospitals connected by miles of tunnels with dozens of entrances & exits. Some of these complexes could hold up to 1,000 troops.
In addition to the use of poison gas & bacteriological warfare (which the Japanese had experimented with), Japan mobilized its citizenry. Had Olympic come about, the Japanese civilian population, inflamed by a national slogan – “One Hundred Million Will Die for the Emperor & Nation” – were prepared to fight to the death. Twenty Eight Million Japanese had become a part of the National Volunteer Combat Force. They were armed with ancient rifles, lunge mines, satchel charges, Molotov cocktails & one-shot black powder mortars. Others were armed with swords, long bows, axes & bamboo spears. The civilian units were to be used in nighttime attacks, hit & run maneuvers, delaying actions & massive suicide charges at the weaker American positions.
At the early stage of the invasion, 1,000 Japanese & 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 & 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 & 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 the war. Intelligence studies && 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 2 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 & Germany. The world was spared the cost of Operation Downfall, however, because Japan formally surrendered to the UN September 2, 1945, & WWII was over. The aircraft carriers, cruisers & 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 & 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 & is not told in our history books is something for which all Americans can be thankful.
