"WW2 WHAT IF: A 1943 Japanese Invasion Of Australia?" Topic

What IF it had taken the Allies much longer to regroup and Japanese expansion had continued well past 1942 …

A) Would the Japanese have preceded their 1943 invasion of Australia with airstrikes of cities, bridges and other key sites? If so which?

B) Which Japanese assets do you think would have been included in the first wave of the invasion?

C) What Australian/Allied assets were available on the Continent to deal with such a wave?

D) Would the Australian/Allied (and militia/guerilla) units on the Continent have been able to hold off or slow the Japanese for, say, one or two years until other Allied help finally arrived?

Thanks

Dan
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Supply lines….

You don't need an army to defend Australia. If the sharks, crocs, snakes and spiders don't do the job, the ants will eat what is left. Ever pitched a hoochie on a bull ant's nest? It isn't pretty.

Anyway, when I was in high school I read a book called "Battle of Sydney" by John Vader which deals with this exact subject. It was speculative fiction. The climax of the novel was a banzai charge over the Sydney Harbour Bridge.

Cheers,
JohnG

Platipus01au: "Ever pitched a hoochie on a bull ant's nest? It isn't pretty."

"Bull ants"? Are they anything like the Central/South American bullet ants?

Dan

The Japanese could not even keep Guadalcanal by the beginning of 43 against a US force that was still not very strong. Any scenario involving the Japanese being able to force Australia out of the war is far fetched at best. Taking and holding a couple northern cities would have been the absolute limit of their ability under almost any condition.

Dynaman8789: "Taking and holding a couple northern cities would have been the absolute limit of their ability under almost any condition."

Ok. Let's go with that then. Darwin and one or two others.

What would Australians have done next? Wait it out or fight?

Dan
PS. So let's assume that whatever the Allies already had in place in the Pacific by early 1942 was all there was for another year or two, at least. In other words, assume that the US was never there to kick the Japanese out of Guadalcanal in 1943 and that Japan had not suffered any significant losses or setbacks elsewhere to the Allies, and that they had continued their expansion well past 1943.

Bull ants"? Are they anything like the Central/South American bullet ants?

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OMG! 40mm long? That's a monster ant.

I read somewhere that the croc situation around Darwin was pretty scary. If the Japanese had taken it, wouldn't the crocs have helped them serving as a natural deterrent against night raids by locals?

Dan

Would they bother a land invasion of Oz, when the allied naval would always be a menace.

Why not push west and attempt a surrender of British India?

DB

The great thing about 'what if' games is that you can write anything you like in to the back ground to make the story fit the game.

You can do as you mentioned re the US navy not being able to what they actually did, supply lines can be created and extra forces recruited and sent to occupy Australia.

Ok, then. If you must have a reason for the WHAT IF …

The Allies felt the need to dedicate all their production and troops to stop Hitler as quickly as possible. And so, the Pacific theater had to wait longer, another year or two, until the European one was dealt with completely. Surely the idea of fighting simultaneous ones was considered, at least for a time, and at least by the US, right?

So … what would have that done to Australia and most of the Pacific?

Dan
PS. I don't think that generation had a fear of thinking out of the box and into considering unpleasant worst-case-for-us-but-best-case-for-them scenarios. At least not the ones I've ever met in person.

> PS. So let's assume that whatever the Allies already had in place in the Pacific by early 1942 was all there was for another year or two, at least.

Can't do it, that is the world of fantasy.

Dynaman8789: "Can't do it, that is the world of fantasy."

Lol. You CAN'T or you WON'T consider it? :)

Dan
PS. I wonder how many times the Allies and their enemies uttered the word "inconceivable" after something did happen.

CC, cannot see it happening. In oder for your scenario to jibe, the Japanese would have had to not attack Pearl Harbor, coupled with stagnation in the war against Hitler on both the West and Eastern Fronts. That is quite a few major leaps to make, each with their own cascading backwards-what-if steps… but it is the only "conceivable" (lol) instance in which the US stays concentrated on Hitler and leaves the Japanese more or less alone for another 12-18mos, and then you have to figure a "logical" reason for the Japanese to even WANT Australia.

If anything, I could see them attempting to neuter the military and material resources to hamper their ability to projecting power from home, but not hold land… they had their hands full still trying to keep China, Burma, and other SE Asia under heel to try to add Australian invasions into the mix.

(my opinion.)

Actually allowing the Japanese to invade something as big as Australia might have been the perfect way to defeat them. Japan was already mired in China and was busy scattering their forces trying to defend any rock that refused to stay below the high tide.

Australia would have drained Japanese resources even further.

It woiuld have takne the cooperation between the IJN and the army, something that was lacking the entire war.

If Miday had gone the other way, I could see it as something in the late summer to fall of '42.

It would have taken the stripping of forces from all the recently occuppied areas as well as major forces from Manchuria and China. Theoretically possible given the desperation between Russia and Germany, but not a risk the Japanese may have been known for.

A northern landing with little opposition and a drive down the coastal belt would have been most likely, leaving the big empty centre as a wasteland. Even with that, logistics and supply would have been an absolute nightmare for Japan.

While a very fair defense would have been offered, I think that psychologically, it would have changed the priority away from the 'Hitler First' strategy.

One aspect that might have helped was to have decalred the Dutch East Indies and French Indo-Chna as independant as long as they provided support as allies. That might have given them another million or so troops and slightly simplified logistics a bit, but probably not enough. Mind the last thing in the Japanese mmind was to grant either of these independance, they wanted total control and resources. Arming another million or two allied troops is another question, however they did manage it with having a million chinese troops fighting for their behalf of the Japanese already.

An invasion of Australia? That's a pretty big what if.

IIRC, there was a lot of pressure for Europe first by the US's allies, but an equal amount of pressure coming from the US population (political pressure too!) to go after Japan. After all, as the reasoning went, it was the JAPANESE who attacked the US at Pearl, and it was the JAPANESE who attacked US forces at Guam, Wake, the Philippines, and elsewhere. In general, the US sent the bulk of its troops to Europe, BUT!, it sent the bulk of its navy and virtually the entire Marine Corps against the Japanese. We also sent major Army ground and air forces into the Pacific.

MacArthur arrived from the Philippines during March and took command of the forces that were dispatched to reinforce him in the Philippines. He was also reinforced with two National Guard divisions and significant other forces. The Marines rushed in both of its divisions too. Indeed, at various times much of the Navy's remaining surface units, especially its carriers, were sent to the region too. That was a LOT of forces that found themselves in the South Pacific and it continued to grow.

Basically, the US tried to do BOTH. That is it deployed the bulk of its ground forces to Europe, but sent significant forces to the Pacific as well. Those forces went a long way towards smashing Japanese forces in the South Pacific and thus finally blunting the Japanese offensive in 1942. This would give a basic operational pause (besides fairly minor actions in the South Pacific and New Guinea) until 1943, with the major offensive kicking off in 1944.

Also, don't forget the AIF! The Japanese rampage in '42 alarmed the Aussies enough for them to demand the return of the AIF which was easily a corps sized force of superb infantry.

All together that was a powerful grouping of land, air, and naval forces. It proved to be sufficient to blunt the last Japanese offensives in summer of '42 in the Solomons and New Guinea and to begin the counteroffensives during the fall which saw the end of the Japanese expeditionary forces on BOTH Guadalcanal and Buna.

And therein lies the rub. By summer of '42 the Japanese offensive was running out of steam. The Japanese crashed through the eastern Pacific like a bull in a china shop, but it did so with pretty minimal force. I seem to remember that the Japanese Army only allocated 10 divisions towards seizing allied colonial possessions including the Indies. 10 divisions is roughly the same sized force that the modern US Army can field today (in theory). It took a huge effort by the IJN and merchant marine to move those troops all over the place and support them.

That just isn't a large enough force to do everything they did historically AND take Australia. Heck, I bet they would need at least another 10 divisions just to take down Oz. The Australians had several militia divisions (they were of mixed quality, but showed a lot of promise, just look at the 39th Battalion's epic fight on the Kokoda Trail) and they were in the process of being reinforced by the AIF (another 3ish divisions of mostly experienced troops) AND roughly two US division of questionable to fair quality (the 32nd and 41st Divisions).

That's a lot of troops to defend Australia. Granted they would be of mixed quality, but in the real history of the war they were enough to turn the tide in New Guinea. Plus I would imagine that the 1st Marine Division would have gotten involved too. So I would have to question if 10 divisions aimed specifically at Australia would have been enough. Where would those troops have come from anyway? China/Mongolia? The Japanese Army would have balked! They were looking to a future war with the USSR and were stingy with giving up land forces.

Finally, the Japanese would have had to defeat the US Pacific Fleet too. Maybe that could have happened at Midway. But it was that fleet that allowed reinforcements and replacements to arrive in theater.

So for your scenario you would need the Army to change its mind and look west rather than east then you would need to defeat the US Pacific Fleet enough to isolate Australia. That could have happened at Midway, but changing the Army's mind? Rather doubtful! You would also need the US to redirect a lot of effort to Europe too. That would have made Churchill a happy fellow, but it would have ticked off a LOT of US voters who wanted to punish Japan NOW. Politicians can weasel out of a lot of stuff, but they do keep an eye on the public's mood. In 1942 that was very much "when are we going after the Japanese!?!"

Dan,

Interesting question. Unfortunately this is an area where my lack of expertise limits my ability to contribute.

However, I think you have gotten some interesting responses(patrick r, troopwo, tgunner). I think it would revert to what would Japan gain from attacking Oz as opposed to going in another direction. Which move would provide the most direct benefit?

Dave
WargamingMiniatures.com

I'd think it would have taken about everything the IJFs had that was not in China. And I'd think even then in the long run they'd fail.

Patrick R does make an excellent point.

"Actually allowing the Japanese to invade something as big as Australia might have been the perfect way to defeat them. Japan was already mired in China and was busy scattering their forces trying to defend any rock that refused to stay below the high tide."

Perfect "Sun Tzu-like" thinking. Use the enemy's strongest drive/motivator against him. In this case complete "control" of Australia and its resources. Make them think it's achievable and worthwhile.

An attempt at invading and (specially) at controlling Australia would have left the Japanese in a very weakened situation. Even more so if Japan became bogged down fighting drawn out ghost-like resistance units on their own home turf.

The next obvious question might be … would non-Australian Allied units have fallen in line and accepted the local Australian defense command structure and guerilla strategy, even after being cutoff from their leaders back home?

Dan

Invsde Yes, Successful Invasion not so much

Take a few northern cities, then take New Caledonia and New Zealand. That would have given them the base of operations to strangle supplies/reinforcements getting to Australia.

They could cetainly have invaded Australia and captured Darwin and maybe a few other cities

Very shortly after that point logistics (never the strong point for the IJN or Imperial Army) plus the local conditions would make it very unpleasant; I suspect a strategic withdrawal a la Guadacanal would have been in the cards

would non-Australian Allied units have fallen in line and accepted the local Australian defense command structure and guerilla strategy, even after being cutoff from their leaders back home?

That is basically what happened in the PI after the US/PI surrender in the Winter of '42. Some US Troops along PI Guerillas fought the IJFs. And waited until Mac returned in the Fall of '44 …

Tgunner has it right. FDR would have found it politically impossible to ignore the Pacific. And what could have been done with more troops pumped into Europe? The Brits weren't ready for an invasion of France. They were leery of Italy. And the major campaign in Europe in 1942-43 was the Battle of the Atlantic, with the air offensive coming second.

Like I said, with a best case scenario of winning Midway, army-navy co-operation and even contingents from occupied areas, best they could have done was a landing and a weak strength drive down the east coast.

Given their logistics and maratime strength, after six months any survirors would have been living off tree bark.

Landed at best, but never to have taken over or even controlled.

It does open up some interesting possibilties.
I suspect a contingent of British, Indian and even possibly South African forces on the west coast. O course in the east, they would have had major US help.

I could see the Japanese landing on the west coast and establishing major naval bases at Fremantle, Albany and Exmouth. Effectively cutting off convoy supplies to the UK via the Suez. They would have been unopposed, and they would have been more than capable of defending the most isolated cities in Australia. Plus they would have access to the richest iron ore deposits in the world.

IF the Japanese had won Midway decisively and then taken the Hawaii, they could get the needed breathing room vs the U.S. I could see them turning to Australia. But I think you'd have to be mad to WANT to fight Australians, but they COULD do it.

The Japanese can't take Hawaii even if they win a Midway. They didn't have the logistics.

As has been said they didn't have the logistics to take Australia. Besides the IJA wasn't interested in Australia as it's way too big a job.

The big question is why the UK and US are sorta-kinda out of the picture – but enough of that.

A) Would the Japanese have preceded their 1943 invasion of Australia with airstrikes of cities, bridges and other key sites? If so which?

Yes, North (Darwin, Broome) and East Coast (Cairns to Sydney).

B) Which Japanese assets do you think would have been included in the first wave of the invasion?

Assume the worst.

C) What Australian/Allied assets were available on the Continent to deal with such a wave?

By 1943 assume Australia has a large enough continental defence capability.

Army in 1939-ish, Army hadhttps://en.wikipedia.org/wiki/Second_Australian_Imperial_Force#Structure Infantry=(4 Regular and 8 Militia Divisions)
Armour=(1 Regular and 2 Militia Divisions). Assume if this scenario eventuated, the number of Divisions and amount of kit would have been increased and Divisions all based in Australia.

RAAF
link Assume some 3000 planes like the First Tactical Air Force had in 1945. Assume if we didn't have these, we might get orphan US, British etc assets to make up to 3000 planes.

RAN
Assume a competent medium Navy (say 100 surface combatants) probably no match for battleships and numbers of heavy cruisers but aggressive, well led and well trained.

Add in
Stockpiles of chemical weapons (maybe biological agents as well)
A scorched earth policy (maybe not the mythical Brisbane line but similar – concentrating on the South East, where the population centres and industry were).

D) Would the Australian/Allied (and militia/guerilla) units on the Continent have been able to hold off or slow the Japanese for, say, one or two years until other Allied help finally arrived?

Possibly, but the first goal would be to stop (most of) them before they land. RAAF was large enough and distributed enough to attempt this. Navy would have supported. Army and RAAF would offer a major threat to any invaders that landed on our soil (oh, the commandos and such would also have been available for mischief behind enemy lines).

Slightly different take. I'll argue Axis lost WWII in last 6 (or 7) months of 1942. Midway. Guadalcanal. Alamein. Stalingrad. Torch Landings. Had Axis won each of those battles decisively then they had a shot, albeit a long shot, at winning the war. In that case Australia might have been invaded and outlying areas of occupied. Otherwise not a chance. You needed the aforementioned Axis wins in Europe to make sure Pacific could not be reinforced. Cheers!
.

1943 would have been too late.

Makes me try to remember the equipment holdings of the 1st Armoured division at what dates?
Make a pretty one sided battle.

IIRC, one of the guys here told me when he was stationed at Ft.Lewis, WA. In the '80s or '90s the JSDF would ship their MBTs[Type 61s ? STA 1-3s ?] to use the training areas on Lewis and at Yakima. I guess since Japan does not have the space for such maneuvers, live fire, etc.

So one could say, the Japans finally did land forces on the US West Coast. Only about 30-40 years later !

What IF it had taken the Allies much longer to regroup….

13 of the Essex carriers were order before Pearl Harbor. There were close to 100 destroyer in the shipyards.

Here is a picture of a Australian Bull Ant

Some more information on them.

Makes you think of the movie "Them"

As for an Invasion Japan did not have the manpower needed to take and hold Australia.

The Outback alone would have killed off thousands.

I understand the desire or interest in creating wargaming scenarios, or even just alternative history mind exercises. But for me any scenario of Japan invading Australia … and by this I mean a serious invasion to conquer or control a significant portion of the Australian landmass, is far enough removed from the reality of the times that it is not much different than the steam punk or SS Space Marines kinds of fantasy.

If that's your gig, fine, I have no objection. I mean, I used to play Star Fleet Battles with miniatures (I flew Klingons … today is a GOOD day to die!) and that is certainly not based on historical fact. I view it as a flight of fancy, that defies any reasonable assessment based on historical analysis. But it may be a highly entertaining flight of fancy for some.

Far more reasonable from a historical perspective, I believe, is the concept of limited ground actions. Imagine, for example, not just an air raid but a IJN Special Landing Force raid on Darwin.

What would have happened if, like they actually did in the Aleutians, the Japanese decided instead to put some troops on the ground in Darwin. Perhaps their objectives would have been to disrupt any use of Darwin as a base of supplies, destroying the port facilities and most of the town in a hit-and-run of 3-5 days duration. Or perhaps their objective would have been to bait a trap, occupying the town to entice USN and Commonwealth fleet units into decisive action on Japanese terms.

This kind of "invasion" might be closer to a historical potential. We can look at the forces that were historically available and ask "what if"?

So let us presume that the Japanese achieve a significant victory at Coral Sea. At that point, rather than going to Midway, Yamamoto decides to draw the USN into his trap closer to his own backyard. If he takes Darwin the USN will certainly respond. But with Japanese forces now on the South coast of Papua-New Guinea, and a growing strength in the Solomons, he has over 1,000 miles of sea lanes through which he can use his fleet submarines, fast carrier air groups and ground-based naval air forces to harass and weaken the US fleet before he brings his battleships in for decisive action.

In the meantime, the Australian government would be trying to get some kind of force into position to counter-attack and retake Darwin from the landward side. Given the distances and poor infrastructure the preferred approach would be along the coast, but again, with the IJN parked offshore, that might not be too realistic.

Views? Opinions? Quick observations of how much dumber I am than a Red Bull Ant?

-Mark
(aka: Mk 1)

far enough removed from the reality of the times that it is not much different than the steam punk or SS Space Marines kinds of fantasy.

SS Space Marines !!!!

I flew Klingons … today is a GOOD day to die!

Qupla' !!!!!

If the Japanese successfully captured Port Moresby the'd follow up with a port inside the Great Barrier Reef along the NE coast, maybe Cairns or Townsville? Then feed all the Guadalcanal resources into defending it. Also, capture Horn Island with an airstrip to control the Torres Strait. Darwin is too far from Port Moresby to assist in its defense.

Darwin is too far from Port Moresby to assist in its defense.

True, that. But is it relevant?

With all of the Dutch East Indies in Japanese hands by mid-1942, and the IJN still at virtually full strength, what meaningful need is there for help in the defense of a Japanese-held Darwin?

The idea is not to defend Darwin, but to entice the USN to try to reach Darwin. Just as Midway, if taken by the Japanese, would be indefensible on it's own. The very fact that it was indefensible, combined with the fact that it was intolerable to leave it in Japanese hands, would serve to bait the trap. I see Darwin as similar, but with the advantage (from the IJN side) that the USN must sail PAST the Solomons and Port Moresby before they even get to the IJN trap. That means more perfect information for the IJN about the USN forces, as well as many opportunities to degrade those USN forces along the way.

Seems a reasonable what-if. Kind of better, historically, that they chose Midway. Even with effective radio intercept and decoding, I'm not sure what could have been done if they had chosen to go Darwin instead of Midway. Maybe sail a token / BB-based force to the Solomons, then beat a retreat, while the fast carrier task forces went around the south of Aussie-land? In the dead of Antarctic winter? Hmm, not liking that scenario much, but … ?

-Mark
(aka: Mk 1)

Actually I meant the other way around: Darwin was too far away from Port Moresby to defend Port Moresby. Thus the attack on Horn Island to control the Torres Strait from the air and Cairns or Townsville to control the passage inside the Great Barrier Reef. Moresby would attract fleets as well as or better than Darwin because it would threaten the population center of Australia more seriously (around Sidney). Moresby and Townsville/Cairns would be mutually supporting, Darwin is just stuck out there somewhere.

OMG, now that's one huge ant!

Scratch off Australia from my bucket list then. :(

Dan

I think a Japanese occupation of a north-coast Australian town would elicit as much reaction as a German occupation of the Channel Islands. It would serve nor deny the enemy any strategic goal, you'd have to either resupply it or abandon it and the enemy would create mayhem with your supply lines meanwhile. Remember how rubbish IJN ASW was.

Land-grab invasions tended to achieve nothing; the Aleutians, Madagascar, the Andamans. Unless the aim as Mark says is to provoke a battle that the enemy must fight but wouldn't otherwise choose to do so, there's no point. Guadalcanal made perfect sense because Japan couldn't ignore it – had she done so the next invasion would have been Bougainville or Tarawa.

Had the IJN tried to hold Darwin, I reckon there would have been a six-carrier USN raid on Tokyo every other week and naval bombardments of coastal cities until their carrier fleet headed north…

By the way, I LOVE how the map in the OP doesn't consider there to have been any major battles in the Burma theatre…

The real question of course is what will be the tanks fighting in the Australian Desert Campaign? Chi-Has versus Sentinels? Aussies got Matildas at some stage and a few Churchills later on, perhaps some captured Italian M11s, odds and ends of older British and US kit presumably and of course the mighty Kiwi expeditionary troop of Bob Semples ;-)

The Japanese would have run screaming from the cock and balls on the Sentinel tank's glacis. As would I.

The Sentinel was pretty much "superior" to anything that the IJFs call an "AFV/Tank". But it wouldn't take much !

After a few weeks of life in Queensland, I imagine that the Japanese would leave of their own accord.

Just returned the 50 yards to the holiday house after swimming in the Southern Ocean. Not a shark, crocodile, bull ant or poisonous spider or snake in sight.

I believe the Japaneses were stupid to do more in the Philippines than eliminate American naval and air power. The Japanese committed an immense amount of ground forces to defeating an essentially isolated, yet highly defended American outpost. If the Japanese had struck at Australia, they would have won and there would have been no base of operations to effectively stage a retake of MacArthur's operational area. American forces in the Philippines would have at best, been isolated and Japan could have dictated an armistice as early as late 1942.

The Philippines, in an abstract way was supposed to be the American Dien Bien Phu, which it was, due to American defeat, but because of lack of successful follow-through in the southwestern Pacific, really made it more like Khe San, as the Americans reclaimed the Philippines. Just say'in.

Distance from Darwin to the next Northern City – Brisbane by modern roads 3,421.9 km

To Cairns 2,847.9 km pop 15,700 in 1944 hardly a city back then.

Could be a bit of a long frontage to cover with a couple of divisions?

Meanwhile their already inadequate Merchant fleet disappears to subs off the coast of Australia.

There were secret plans to cede half the continent to the invaders and let the country defeat them. This would have been an extremely unpopular decision, but you can appreciate the logic.
Google search 'Brisbane Line'.
Good fodder for What-If players and theorists.