This Day in History

[raketenjagdpanzer]

One oft-overlooked fact was that the Japanese also had 3000 aircraft remaining - most outdated, or in poor condition - to sortie against the invasion fleet. This amounted to, by US estimates, two to three destroyed carriers of the line (destroyed as in, totally sunk) plus a lot of other smaller support ships. That's assuming CAP and perimeter defense ships worked entirely as planned.

The invasion also called for the softening up of enemy positions with atom bombs, so even more would've been used. And US troops would've marched straight into the fallout zones.

[dragoon500ly]

Originally Posted by raketenjagdpanzer

One oft-overlooked fact was that the Japanese also had 3000 aircraft remaining - most outdated, or in poor condition - to sortie against the invasion fleet. This amounted to, by US estimates, two to three destroyed carriers of the line (destroyed as in, totally sunk) plus a lot of other smaller support ships. That's assuming CAP and perimeter defense ships worked entirely as planned.

Okinawa cost the USN dearly in ships sunk and damaged. But it could have been much worse. The Kapanese military followed their normal doctrine and went for the capital warships. With the invasion of Japan, their targeting lists were changed...the kamikaze's would instead attack troop transports as they neared the coast

[dragoon500ly]

June of 1945 saw the Allies advancing to within striking range of the Japanese home islands. The Philippines were mostly recaptured. The Imperial Navy had been devasted in the battles of the Philippine Sea and Leyte Gulf. The Japanese merchant marine was a shell of its former self, gutted by U.S. submarines, air power and mines. The fall of the islands of Iwo Jima and Okinawa gave the U.S. bases for reinforcing the strategic air campaign against Japan. Germany had finally surrendered and Japan faced the wraith of the United Nations, alone.

The Japanese plan for their final battle was KETSU-GO (Decisive Struggle), it had the twin objectives of defeating the Allies militarily, as well as psychologically. Its goal was to inflict so many losses upon the Allies, that they would be forced to abdanon their unconditional surrender policy and enter negotations with Japan.

The Japanese had several advantages that might have lead to their success. First, being islands, Japan would have to be attacked via amphibious assault. Second, even groaning under the weight of the American bombing campaign, Japan could still produce some 1,200 aircraft a month and had sufficient weapons and supplies to equip its land forces. SInce the Japanese would be fighting on their home islands, their gorces would not be isolated as they had been for much of the war. The Imperial General Headquarters was optimistic that they would be able to force the Allies to the peace table and that they would be able to keep the majority of their possessions.

IGHQ anticipated that the Americans would first attack Kyushu and seize harbors and air fields to support later landings and they built up their fortifications not only on the beaches, but inland as well. Their goal was to engage the Americans and either defeat them or inflict unacceptable losses. The kamikazes would be used during the initial phase of the American assault landings to strike their assault transports, massive losses to the assault troops would firther delay and disrupt the American invasion.

The Japanese would also enjoy the advantage of the terrain, much of Kyushu was mountainous. The Japanese would be able to defend in depth and make the Allies pay for every yard that they gained. IGHQ intended to reinforce Kyushu during the battle. Even if the US eventually conquered the island, the assault on Honshu would be delayed, making Wasington that much more willing to negotate.

The 16th Area Army was charged with the initial defense of Kyushu. US Intelligence placed its strength at two armored and no less than fifteen infantry divisions. To dispute American airpower, the Japanese had 4,000 army and 5,000 naval aircraft available (roughly half of these were of these were obselete aircraft to be used as kamikazes). The IJN was responisble for mainting control of the communications between the home islands and with Manchuria. By August, 1945, the IJN had six aircraft carriers, four battleships, eleven cruisers, forty-two destroyers and fifty-eight submarines as well as thousands of special attack craft (kamikazes), ranging from midget submarines, motor boats loaded with explosives, to human guided torpedoes as well as divers carrying satchel charges.

[dragoon500ly]

The final US plan for the invasion of Japan was Operation Downfall. It consisted to two components: Operation Olympic, the invasion of Kyushu, to secure naval and air bases and Operation Coronet, the invasion of the main island of Honshu.

The Joint Chiefs of Staff, in the summer of 1945, had three basic choices for Downfall. First, to encircle Japan by invading China, establish bases there and use those bases to first blockade and then to invade the home islands. Second, to isolate Japna via naval blockade and massively reinforce the existing bombing campaign and force Japan to surrender without having to invade the home islands. Third, was to assault Japn through amphibious invasion and force the Japanese to surrender by seizing Tokyo and key industrial areas.

The JCS strongly debated these courses, the naval supporting option two and the army supporting option three. The first option was rejected as it would needlessly run up casualties without forcing Japan to surrender. Other worries were that the growing war wariness would force an end to the war before final victory was achieved. There was also the very real concern that Kapanese forces outside of the home islands would continue to fight on. On May 25, 1945, the JCS issued a directive to launch an amphibious assault on Japan. General Douglas MacArthur was placed in command of Operation Olympic.

On 18 June, the JCD presented their plans to President Truman, who issued the go order for Downfall. And on July 26, he, British Prime Minister Clement Atlee and Soviet leader Josef Stalin issued the Potsdam Declaration warning Japan to surrender of face "total destruction". The Japanese rejected this ultimatum and on July 30, the JCS directed Generals MacArthur and Wedemeyer (commanding in China) and Admiral Nimitz to coordinating plans for Downfall. Operation Olympic would jump off first, followed four months alter by Coronet.

The British contribution to Olympic would consist of the British Pacific Fleet and elements of the Royal Air Force. The British would contribute more forces for Coronet. One of the factors limiting the size of the British forces were the deep concerns that Japanese units the remainder of the Far East would go on fighting, even if the home islands did surrender. It would be necessary to retain forces for posisble use. The British still planned for a force of from three to six divisions to be committed to Cornet. The specific units were never designated, but would have most likely consisted of at least one British, Australia, New Zealand, India and possibly a Canadian infantry divisions.

[dragoon500ly]

The logistical problems supporting Downfall were immence. The American line of supply streatched for thousands of miles back to the United States. It was necessary to build bases, support facilites and warhouse faciliteis.

Downfall called for a force of forty-two divisions. This included thirteen reserved for Olympic and twenty-nine for Coronet. Twenty-seven of these divisions were already present in the Pacific, another fifteen would have to be redeployed from Europe and a strategic reserve of an additional fifteen divisions would be maintained in the United States.

The Philippines, Okinawa and other Pacific islands would be developed as base areas for Downfall. Not only would the massive combat force need to be sustained, but the tens of thousands of support troops, the engineers, supplu, ordnance, medical, transport and administrative personnel would have to be housed and supplied.

Initially, the plan was to abandon existing bases and build new, much larger bases. But this would require far too much transportation effort to move the existing bases. Two choices were made, first was to expanded the existing bases, coupled with new base construction at strategic areas, and second was to make shipments of men and material, straight from the United States and directly to the assault areas. There were even plans to invade the northenmost island of Hokkaido, to open supply lines to Russia in the event of Soviet participation in the invasion of Japan.

[dragoon500ly]

Imperial General Headquarters would defend the home islands with six Area Armies. The 5th Area Army (HQ in Sapporo) would defend Hokkaido with five infantry divisions, the 11th (HQ in Sendai) with six infantry divisions, 12th (HQ in Tokyo) with two armored and twenty infantry divisions, 13th (HQ in Nagoya) with seven infantry divisions (two forming) and 15th (HQ in Osaka), with eight infantry divisions, Area Armies were responsible for the main island of Honshu and the 16th Area Army (HQ in Fukuoka), with two armored, fifteen infantry divisions was responsible for Kyushu. In reserve, in CHina) were the 6th Area Army (HQ in Wuchang-Hengyang) with eleven infantry divisions, the 23rd Area Army (HQ in Canton) with three infantry divisions and the North Chine Reserve Army, with one armored and five infantry divisions.

Supporting the defense were three Air Armies, the 1st was based in northern Honshu and fielded 600 kamizake and 500 combat aircraft, the 6th Air Army was based in southern Honshu and fielded 1,000 kamizake and 500 combat aircraft, in reserve was the 5th Air Army (in Korea) with 500 kamikazes and 200 combat aircraft.

The initial forces for Operation Olympic would be the 6th Army, consisting of the Fifth Amphibious Corps (2nd, 3rd and 5th Marine Divisions), First Corp (25th, 33rd and 41st Infantry Divisions) and Eleventh Corps (1st Cavalry, Americal and 43rd Infantry Divisions), in reseve would be the Ninth Corps (77th, 83rd and 98th Infantry Divisions. Army reserve would consist of the 40th Infantry Division and the 158th Regimental Combat Team.

The initial forces for Operation Coronet would be the Eighth Army, consisting of the Tenth Corps (6th, 31st, 81st Infantry Divisions) , Thirteen Corps (3rd and 6th Armored and 1st Infantry Divisions) and the Fourteenth Corps (32nd 93rd,75th Infantry Divisions) as well as the Tenth Army, consisting of the Third Amphibious Corps (1st, 4th and 6th Marine Divisions) and the Twenty-Fourth Corps (37th, 38th. 96th Infantry Divisions). Force reserve would be the 11th Airborne Division. Follow-up forces would consist of the First Army
(2nd, 8th, 9th, 24th, 28th, 69th, 76th, 87th, 89th, 104th Infantry and the 101st Airborne Divisions).

The Commonwealth would be represented by three divisions (2nd British,
7th Australian, and 5th Indian and the 3rd Commando Brigade); these are very suspect and any specific knowledge would be gratefully included!

[dragoon500ly]

Operation Downfall was actually implemented, in part. In March, 1945 Operation Starvation, the mining of the Japanese coastal waters was launched. This was designed to isolate Japan from the rest of its empire and to paralyze much of its transport. Even through the mining campaign sunk very few ships, it was effective in that the IJN had to mount minesweeping operations for several days prior to any convoy, this would alert American reconnaissance aircarft and air strikes would sunk yet more of Japan's shrinking minesweeper force

Starvation cut Japan from its overseas supply of resources. The lack of oil crippled the IJN and their air forces. Because of fuel limitations, the Japanese could not train their pilots, and major fleets were forced to remain in port, to be raided at will by American air power. Food shortages led to general malnutrition in the civilian population.

At the same time, the B-29 force launched the first of its incendiary attacks against industrial cities. They destroyed the centers of Tokyo, Nagoya, Kobe, Osaka and Yokohama in massive firebombing raids which killed over 300,000 civilians.

Beginning in May 1945, Admiral Halsey's Third Fleet was ordered to "attack Japanese naval and air forces, shipping, shipyards and coastal objectives." The Third Fleet, with the attached British Pacific Fleet commenced operations on July 1, 1945. First gaining air superiority by destroying 550 Japanese aircraft in air-to-air combat and in raids on their airbases. Airstrikes were also launched in the warships of the IJN, this resulted in the loss of many warships and effectively ended the threat of the IJN. THe Americans and the British also used naval gunfire to bombard Japanese coastal fortifications.

[Raellus]

There's a logical fallacy here that I'd like to point out. I don't think one can justify the killing of Japanese civilians in Hiroshima and Nagasaki by arguing that the Japanese [military] killed many civilians throughout Asia. The women and children and senior citizens of Hiroshima and Nagasaki weren't the ones killing civilians in China and elsewhere, so they didn't really "earn" the fate that befell them. Most people wouldn't argue that Yugoslavian or French or Ukranian or Polish (etc.) civilians deserved to get shot by the Nazis as reprisals for partisan actions. That, in most people's minds, would constitute a clear war crime. Unfortunately, this standard gets tossed out the window when it could be applied to "enemy" civilians. I guess that I just don't believe in collective punishment.

From the standpoint of projected military and civilian casualties for planned invasion of the Home Islands, I can understand the reasoning to drop the bombs. Preserving the lives of American and Allied servicemen that surely would have perished during an invasion of the Home Islands is certainly a logical rationale. Considering that the Japanese high command was actively mobilizing civilians, including women and children, to participate in the defense of the Home Islands, civilian casualties in Japan would likely have been much higher than the toll exacted by the atomic bombings. In that sense, the bombings most liklely saved many Japanese civilian lives. There's a cold mathematical logic there that it is difficult to argue against.

That said, I wish a purely military target was selected for the first bombing, instead of a civilian population center. I think that would have been the more ethical path to tread.

To complicate things further, a secondary motive of the bombings was to demonstrate American power to the emergent Soviet Union. That this display cost tens of thousands of third party civilian lives is kind of messed up.

[rcaf_777]

Originally Posted by dragoon500ly

The Commonwealth would be represented by three divisions (2nd British, 7th Australian, and 5th Indian and the 3rd Commando Brigade); these are very suspect and any specific knowledge would be gratefully included!

Canada's Force would have been the Canadian Army Pacific Force

Canadian Army Pacific Force

The Canadian Army Pacific Force was raised in 1945 as a field force intended to participate in the last phase of The War Against Japan, an anticipated Allied invasion of the Japanese home islands in the last phase of the Second World War. The CAPF was based on an infantry division structure, however, to increase operability with the Americans, certain units bore US organizational structures and names. As well, Canadian units went into training with US weapons to ease logistical concerns.

Major General Bert Hoffmeister was named to command the division, and the three Infantry Regiments (the equivalent of a Canadian brigade) had battalions bearing the name of those infantry battalions that had fought with the 1st Canadian Infantry Division in Europe. These would formed as 2nd or
3rd Battalion, the 1st being the ones that did fight in Europe.

Detialed Order of Battle can be found here

http://www.canadiansoldiers.com/orga...cificforce.htm