The invasion of Japan might have resembled the Okinawa campaign

Sunday, August 23rd, 2020

The US dropped two atomic bombs on Japan 75 years ago, but what would an actual Allied invasion of Japan have looked like?

A clue can be found in Japan ’45, from John Tiller Software, a hobby wargame that depicts Operation Olympic (a sequel, Japan ’46, covers Operation Coronet). Japan ’45 is a battalion-level simulation involving thousands of U.S. Army and Marine, Japanese, British and French units maneuvering over a 2-D map of Kyushu.

At first glance, the Allies appear to be an unstoppable juggernaut. They field a staggering array of units, including tanks, armored cars, infantry (foot and mechanized), paratroopers, commandos, artillery (towed and self-propelled) and anti-tank guns, backed by fighters, bombers, battleships and destroyers. They enjoy far more firepower and mobility than the Japanese, whose army is mostly a First World War-style force of foot infantry and artillery.

But the unstoppable Allied war machine soon clanks to a halt. For starters, the terrain is not friendly to a mechanized army. In Japan ’45, the map of Kyushu is studded with rice paddies, forests, hills, villages, rivers and streams. The terrain restricts movement to a crawl, and provides natural defensive cover for the defenders. Despite all those Allied Sherman tanks, there will be no dashing Patton-esque blitzkriegs on Kyushu.

And what nature can’t provide, Japanese shovels will. The invasion beaches on Kyushu are studded with minefields, trenches, bunkers and pillboxes. The Allied player can only gnash his teeth as bombs, napalm and one-ton shells from battleships barely scratch Japanese troops embedded deep in their fortifications.

Finally, there is the Japanese soldier to contend with. The core of the Imperial Army was its legendarily tough infantry, which could withstand the hardest privations, and preferred to fight hand-to-hand with the bayonet. Even if their weapons aren’t quite as good or plentiful as Allied equipment, they’re good enough to inflict massive casualties on the invaders.

Playing Japan ’45, as the Allies against the AI-controlled Japanese side, graphically demonstrates that Operation Olympic would have been a meat grinder. U.S. Army and Marine assault troops splashing ashore suffer heavy losses from minefields, artillery and machine guns. Pinned down on the exposed beaches, the riflemen and engineers advance inch-by-inch. Eventually the Japanese are dislodged from their entrenchments, and once in the open, they are vulnerable to Allied air and naval firepower.

But then what? The terrain on Kyushu is too rough and restricted to allow an Allied breakthrough. Once the Japanese defenders are pushed off the bushes, they just regroup inland among the hills and woods, and the Allies have to dig them out again.

The game suggests the invasion of Japan might have resembled the Okinawa campaign, where U.S. troops had to battle through multiple Japanese defensive lines in a grinding battle of attrition that cost 50,000 American casualties — and 400 ships sunk or damaged by kamikazes — before Okinawa was conquered. Like Okinawa, the question is not whether the Allies will capture Kyushu, but what price they will pay for it.


  1. Gavin Longmuir says:

    An old gentleman, now deceased, once told me that as a young soldier he had been loaded onto a ship for the invasion of Japan prior to the atomic bombing and Japanese surrender. He was very glad for the atomic bombing!

    In the hypothetical absence of the Nuclear Option, practically, after some heavily contested landings, the probability is that the Allies would have switched to a siege & continued fire-bombing strategy.

    The US had already jumped past Japanese-occupied islands where the Japanese forces were effectively isolated. Once Japanese forces could no longer threaten the Allies outside the Japan, was there any need to waste US lives to hasten the eventual Japanese capitulation or collapse?

    The USSR had already seized some of the northern Japanese islands very late in WWII — which is why Russia produces oil from Sakhalin today. If Japan had not surrendered, it is interesting to speculate how much further south USSR forces might have moved — given the Soviet willingness to endure very heavy casualties.

  2. Kirk says:

    My take on the invasion of Japan is that they’d have done it, suffered the massive casualties projected in the first phase, which would have likely coincided with the tremendous typhoon that happened historically, and… Well, the invasion foothold would have been held, but the rest of the plan would have been abandoned to go for the alternative, which was basically a “starve them out” siege on a massive scale. Japan would have ceased to exist as a nation and culture afterwards.

    The atomic bomb saved Japan, along with their total surrender. Had there been significant guerrilla-style resistance, and a lot of dead GIs in the occupation force, then Japan would have suffered a lot worse than they did. Fortunately for all concerned, the Japanese rolled over and exposed their bellies properly, and the Americans proved to be magnanimous in victory–Another component. Since we were feeding them, they stayed surrendered, and did what conquered populations with a survival instinct do. Other nations wouldn’t have done that with the Japanese, and it’s a credit to both parties that the hostilities were ended as rationally as they were. For a war fought on such dreadful racial terms, it’s really a complete fucking miracle–If you read and digested the pre-WWII and WWII mass media from the US, and extrapolated? You’d have expected Japan’s total destruction. Fortunately, both parties backed off and did a better job post-war than anyone could have expected.

    But, it could have so easily gone the other way…

  3. Slumlord says:

    And then there was the huge Typhoon that happened in Nov 45 which would have savaged the supporting fleet.

  4. RLVC says:

    Or you could just, you know, call a ceasefire, negotiate a peace, and withdraw the invasion forces.

    Thereby simply not, you know, throwing millions of American youth upon the pyre of the absolute subjection of the one European-like race in Asia.


  5. The American Muse says:

    RLVC, I don’t think that was on the table. The president and much of America was in no mood for a ceasefire, Japan still occupied Korea and numerous other places in the Pacific and East Asia, and frankly the Japanese had made it clear that wouldn’t be giving anything up unless they were pried off it with blood and iron. How, exactly, do you negotiate with a foe that is bound and determined to keep everything he has at the point of a sword?

    Wishful thinking nearly as bad as the anti-nuclear peaceniks.

  6. RLVC says:

    “Japan still occupied Korea and numerous other places in the Pacific and East Asia”

    Who gives a shit?

  7. Lu An Li says:

    Estimated casualties for the Japan invasion were based on the Okinawan campaign. 100,000 Japanese dead and 10,000 American dead. A ratio of 10:1. Two million Japanese army troops on the home islands and to annihilate them would require 200,000 American dead and a total of 1 million American casualties.

    That is just military casualties not including about 400,000 allied POW and civilian still in Japanese captivity. Almost all would have died in a prolonged ground conflict, from abuse and downright murder.

    It can be argued that those figures with hindsight would have proved to be wrong. But planners for the invasion had to have some figures to go with.

  8. Sam J. says:

    Even worse would have been the Japanese putting together their nuke program earlier so that we had to slog it out nuke to nuke with them. As it was they only had one to test off the coast of North Korea a couple weeks before Hiroshima. Supposedly it worked.

    I heard about this from the book,”Japan’s Secret War” by Robert K. Wilcox

    He has a revised version,”Japan’s Secret War: How Japan’s Race to Build its Own Atomic Bomb Provided the Groundwork for North Korea’s Nuclear Program”.

    I’ve commented here and there over the years that the same places the Japanese were said in the book to have created the Japanese bomb are exactly the same places the North Koreans made theirs.

    That Wilcox is correct about them building a bomb is greatly amplified by the existence of the I-400-class submarine. A submarine that could go all the way around the world and whose only cargo was three bomber aircraft. An aircraft carrier submarine.

    When I read the book, in the 80′s I didn’t even know these subs existed. I think they were classified. The US sunk all of them. Maybe that’s why the Japanese Army wanted to continue the war. They would not have able to finish the nuke program though because Russia captured the nuke plants in North Korea.

    Think of the perfidy of the US government that knew, most likely, the Japanese were building nukes and covered the whole thing up to prepare for the challenge of the USSR. If it were widely known that the Japanese were building nukes in WWII what do you think the American public’s response would be? I suspect murder.

    Here’s a forum discussing Japans nuke. I haven’t read it but will.

    There’s other books which I can’t recall the name of that say some of the last missions of the advanced Nazi submarines were to take uranium to Japan. They subs and uranium were surrendered to the Americans instead with the Japanese on board committing suicide.

  9. Slovenian Guest says:

    Sam, here’s a podcast with Robert Wilcox!

  10. RLVC says:

    Back in reality, we “gave” nukes to the Soviet Union, Communist China, India, the Islamic Republic of Pakistan, and Zionist Israel.

    Certainly, we did not wage totalen krieg against these states to prevent them from acquiring these doomsday devices. None of which, I would remind you, have been used in anger.

    And yet you would have me believe that Japan was somehow distinctive for seeking the one technology that would secure its national existence against total subjection at the hand of its mighty aggressor.

    Why does no one ever question the basic premise of WWII: unconditional surrender?

    We can see the results.

    In the East, Bushido Japan was replaced with Communist China; in the West, Warrior Germany was replaced with the Soviet Union.

    Remember: America denoted its first nuke in 1945. Shortly thereafter, it had an arsenal.

    And yet the Soviet Union did not detonate its first nuke until 1949; Communist China did not detonate its first nuke until 1967.

    Four years is the duration of WWII; twenty-two is a whole generation.

    Where is your moral outrage?

  11. Sam J. says:

    “podcast with Robert Wilcox!”


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