What if the Japanese Invaded Australia in World War 2?

[RNG]

This youtube video,

, claims that if Japan managed to invade Australia then World Two would last longer and the Soviet Union would mange to take over much more of Europe, including the whole of Germany and Italy, and Japan would be spilt into a Soviet puppet north and American puppet south. Would this be the case? My thinking was that yes World War Two would take longer, however that would mean the use of nukes may play a role in Europe, perhaps then Germany surrenders but tries to make a peace where America is their overlords instead of the Soviet Union. Or would Hitler, if he survived the nukes, be really stupid and fight on to the end with many German cities getting nuked. Might the German army generals see that Hitler is losing and attempt a coup or assassinate Hitlerstop the bombings and to avoid a Soviet wrath. in order to And wouldn't nukes be used in Japan and they surrender for a treaty similar to our timeline. They also said that the French empire may survive to this day, would this be the case, what about the British empire however would they fare. IDK what do you think? Also what if Japan invaded Sri Lanka or Madagascar, or both?

 

[NOMISYRRUC]

Although Australia was weakly defended in the first half of 1942 the Japanese did not have the troops or the necessary merchant shipping to take advantage of the situation.

You need a POD where the IJA has 10 extra divisions and a merchant marine that was at least 25% larger for an invasion to be feasible in the first place. If they had they could have also taken Ceylon and Madagascar.

 

[Oldbill]

Although Australia was weakly defended in the first half of 1942 the Japanese did not have the troops or the necessary merchant shipping to take advantage of the situation.

You need a POD where the IJA has 10 extra divisions and a merchant marine that was at least 25% larger for an invasion to be feasible in the first place. If they had they could have also taken Ceylon and Madagascar.

Concur. The Japanese simply didn't have enough shipping to even seriously consider it, especially when factoring in the number of other spots they are trying to take/hold. IIRC they started the war with a deficit in shipping tonnage, which is why they made such strenuous efforts to refloat and repair any and every vessel they could get. IIRC there was at least one thread over on the Navweaps forum some time back. Try a search on there.

 

[Look More Closely Later]

Video clip seems to me to start to degenerate into epic fantasy round about the three minute mark, where the person talking starts making wild claims about the Japanese having a fleet (edit: in the Indian Ocean, I think(?)) which wasn't doing much which could have been used (after a successful conquest of New Guinea) to carry out the invasion of Australia with the troops which the Japanese were deciding (by handwave) all of a sudden not to protect the Manchurian border with Russia with...

 

[M79]

https://en.m.wikipedia.org/wiki/Attacks_on_Australia_during_World_War_II

The Japanese supposedly landed on Australia at one point in 1944 for reconaissance I think but to no practical effect. Australia had a plan to shore up defenses at New South Wales and Victoria (along with Tasmania?) if Japan actually landed in force. If the war is in its early stages it *may* be enough to push the Aussies out of the war, more likely the government (and maybe that of New Zealand as well) will request permission to withdraw its troops from Europe for home defense.

https://en.m.wikipedia.org/wiki/Brisbane_Line

 

[elkarlo]

Although Australia was weakly defended in the first half of 1942 the Japanese did not have the troops or the necessary merchant shipping to take advantage of the situation.

You need a POD where the IJA has 10 extra divisions and a merchant marine that was at least 25% larger for an invasion to be feasible in the first place. If they had they could have also taken Ceylon and Madagascar.

Yeah they'd need to have the German and Italian merchant ships make a run for the Japanese empire when their countries declared war. To even give them a decent chance at having a merchant marine capable of sustaining anything but an occupation of Darwin with

 

[Riain]

Invasion doesn't mean total conquest, there doesn't need to be 10 divisions to pinch off a piece of northern Australia for a while with attendant masses of shipping.

What's the shipping requirement for a couple of divisions to take Cairns?

 

[NOMISYRRUC]

If the war is in its early stages it *may* be enough to push the Aussies out of the war, more likely the government (and maybe that of New Zealand as well) will request permission to withdraw its troops from Europe for home defense.

The Australians did withdraw the 3 divisions they had in the middle east but were not allowed to do so as quickly as they wanted. IIRC 2 or 3 brigades were initially sent to Ceylon and made up some of the 6 brigades on the island when the Indian Ocean raid took place and the last division didn't leave the Middle East until after the Second Battle of El Alamein.

IIRC No. 3 (Fighter) Squadron, RAAF remained with RAF Middle East and Mediterranean for the duration and No. 10 (GR) Squadron, RAAF remained with RAF Coastal Command for the duration. There were also the 17 RAAF Article XV squadrons of 18 planned but IIRC 2 of them were sent to Australia with an RAF fighter squadron.

New Zealand didn't withdraw any of its forces AFAIK. The 2nd NZ Division served in the Middle East and Italy for the duration. No. 75 (NZ) Squadron, RAF which was manned by New Zealanders and the 6 Article XV squadrons remained AFAIK. However, that would change if Australia was occupied by the Japanese. But the Japanese could probably have gone on to invade New Zealand in a TL where they were capable of successfully invading Australia.

 

[NOMISYRRUC]

Invasion doesn't mean total conquest, there doesn't need to be 10 divisions to pinch off a piece of northern Australia for a while with attendant masses of shipping.

What's the shipping requirement for a couple of divisions to take Cairns?

I think it does in the context of the OP.

A token occupation of Darwin has been discussed before as an alternative to the unsuccessful Port Moresby operation. An occupation of Australia's NE coast would deny the RAAF and USAAF the bases that they used to bomb the oil installations in Java and Sumatra from.

When this has been discussed before several people have said that had a successful invasion taken place a guerrilla war would have been mounted against the occupying forces from the outback. But I suspect that the Japanese would have rounded up the rural population and replaced them with Japanese settlers.

 

[NOMISYRRUC]

IIRC they started the war with a deficit in shipping tonnage, which is why they made such strenuous efforts to refloat and repair any and every vessel they could get.

Only 63% of their imports were carried in Japanese ships in 1941 compared to 54% in 1937. But the devil is in the detail. The Japanese merchant marine had grown since 1941, but IIRC imports were less in 1941 than 1937 due to the trade embargoes and the disappearance of Scandinavian and British merchant shipping from the carrying trade in the Far East. OTOH the Japanese gradually recalled all their merchant ships between 1939 and the end of 1941.

However, with a POD between 1919 and 1930 the Japanese could have expanded their merchant marine to 9 or even 12 million G.R.T. by the end of 1941 rather than 6 million tons of OTL. E.g. in World War One they built up the capacity to build 600,000 GRT of merchant ships per annum but nearly all of it was lost in the 1920s.

 

[NOMISYRRUC]

Video clip seems to me to start to degenerate into epic fantasy round about the three minute mark, where the person talking starts making wild claims about the Japanese having a fleet (edit: in the Indian Ocean, I think(?)) which wasn't doing much which could have been used (after a successful conquest of New Guinea) to carry out the invasion of Australia with the troops which the Japanese were deciding (by handwave) all of a sudden not to protect the Manchurian border with Russia with...

I've not seen the video. But do you think that if the IJA did have the 10 extra divisions I wrote about they would have been better used in China or even for the Japanese to attack Russia?

I suggested that instead of going south the Japanese attack the USSR before but was told that the Soviet forces in the east would have defeated them easily. Would 10 extra Japanese divisions alter that? Not necessarily finish the USSR off in late 1941 - early 1942, but draw off Soviet forces used for the 1941 counteroffensive which would reduce German losses of troops and territory. Then in 1942 the Germans stand a better chance of reaching the Caucasian oilfields and capturing Leningrad.

No Pearl Harbour likely delays and possibly avoids the USA entering the war.

 

[NOMISYRRUC]

Also what if Japan invaded Sri Lanka or Madagascar, or both?

Neither is possible with the land forces and merchant shipping the Japanese had in December 1941.

However, for all the good the Midway Campaign did them the Japanese would have been better off making a second attempt to take Port Moresby by sea.

Or more ambitiously conducting another Indian Ocean raid. The objective of that would be 4-fold.

1. Stop the W-Allies sending aid to the USSR via Iran
2. Cut the supply line to the 8th Army
3. Stop the export of Middle Eastern oil to Britain
4. Destroy the British Eastern Fleet

Objectives one to three would only produce an interruption of a few months, but they might be enough to help Rommel win the El Alamein series of battles or prevent the Soviets from besieging Stalingrad.

IIRC the Eastern Fleet still had Formidable, Illustrious and Indomitable at the time of the Midway campaign. Sinking them would damage the Royal Navy far more than the loss of Yorktown at Midway damaged the USN and it's very unlikely that the Japanese would loose 4 of their big carriers fighting the British. If Indomitable had been sunk she would not have been available to take part in Operation Pedestal. Malta may surrender.

Achieving objectives 2 and 4 does not necessarily mean Rommel reaches the Nile Delta, but it does mean that the Axis can hold Libya and Tunisia for longer, which delays the invasions of Sicily and mainland Italy which in turn delays the fall of Mussolini. Though all that probably does is prolong the war for lone enough for the atom bomb to be used against Germany.

Does anybody know how important Lend Lease was to the Soviets in 1942? Would the Siege of Stalingrad have been possible without it?

 

[Fred the Great]

A Japanese invasion intended to occupy all of Australia - or at least the major population centres on the eastern seaboard - would have been disastrous . . . for the Japanese. Australia would have been able to meet any invasion on the east coast with two corps of AIF and militia divisions - including armour - and with a US Army corps that was on its way by mid-42. Britain would ship forces to assist because it would be too much of a loss of face not to do so. The logistics massively favour Australia. The numbers would soon favour Australia. Every Japanese ship sunk, aircraft downed and soldier killed is one less they will have to defend their earlier conquests and their own territory later in the war. It may see some divergence of resources that historically the Allies used themselves in the ETO or sent to the Soviets, but it is doubtful this would be such that it would make a great difference. Bottom-line, however, is that the Japanese didn't attempt such a campaign because they never had the resources.

 

[NOMISYRRUC]

This topic has come up several times and I still have some of the notes on my laptop.

Deployment of Australian Army in the Far East December 1941

Malaya

2 Brigades of the 8th Australian Division (22nd and 27th Brigades)​

Ambon & Timor

1 Brigade of the 8th Australian Division​

Rabul

2/22nd Battalion​

Naru & Ocean Island

A small artillery detachment​

Solomons, New Ireland & Admiralties

1st Independent Company​

New Caledonia

3rd Independent Company​

The Militia was mobilised in December 1941. It had 114,000 men in 5 infantry and 2 cavalry divisions (1st to 5th Australian Divisions and 1st and 2nd Australian Cavalry Divisions), in full strength of men, if not weapons and equipment. The 2/40th Battalion was sent to Timor and the 2/2nd Independent Company was sent to Portuguese Timor.

Forces in Australia - 1st Quarter 1942

1 Armoured Division with hardly any tanks
7 Militia Divisions incompetently trained and organised​

Reinforcements

46,000 men of 6th and 7th Australian Divisions (less 1 Brigade in Ceylon)
63,000 men of AIF who had not left Australia
33,000 men in US 41st Division and some USAAF men​

Organisation

1st Army

I Corps - 3rd, 5th, and 7th Australian Divisions
II Corps - 1st, 2nd and 10th Australian Divisions, plus 1st Australian Cavalry Division​

2nd Army

1st Australian Armoured Division, 2nd Australian Cavalry Division and US 41st Division​

III Corps

4th Australian Division​

Northern Territory Force

Part 6th Australian Division​

New Guinea Force

30th Australian Brigade. Joined by 14th Australian Brigade on 14th May
​

The source also says that there were eventually 12 infantry divisions (numbered 1 to 12) of which 8 were Militia and the rest belonged to the 2nd A.I.F.

At the end of 1941 the Second A.I.F. the 4 divisions (6th to 9th) consisted of 12 brigades (16th to 27th) and 36 infantry battalions (2/1st to 2/48th with gaps in the sequence).

It also said that in addition to the above the 2nd A.I.F. also had 4 pioneer battalions, 8 machine gun battalions, the Parachute Battalion, the Papua Infantry Battalion, four New Guinea infantry battalions, the Torres Strait Light Infantry Battalion, the garrison battalions, 8 independent companies (later named commando squadrons) and other unbrigaded infantry units not included in the above lists.

Although the Militia had 8 divisions by the end of 1942 they only had 18 brigades in July 1943 instead of 24 with an average of 3 battalions each. It also says that over the next 2 years 4 of these divisions ceased to exist and a 5th became a training formation. However, that could be because the threat to mainland Australia was receding.

Australian Armoured Forces

The source I used for the Ordbat of the Australian Army in the first quarter of 1942 also says that in May 1942 the armoured formations of the Australian Army consisted of:

1 Armoured Division (1st and 2nd Armoured Brigades plus divisional troops)
1 Motor Division - formerly the 1st Cavalry Division (1st and 2nd Motor Brigades plus division troops)
2 Motor Division - formerly the 2nd Cavalry Division (6 armoured brigade and 3 motor brigade, plus divisional troops)
3 Armoured Tank Brigade (1st, 2nd and 3rd Tank Battalions)​

However, there weren't enough tanks in Australia to equip them with. The Australians couldn't obtain any from abroad quickly, hence the Sentinel tank programme.

To finish off its history, according to the Australian Encycopaedia:

The motor divisions had been formed from the peacetime cavalry divisions. A second armoured division, organized with one armoured brigade and one motor brigade, was formed by converting one of the motor divisions. It was hoped to form a third armoured division, but lack of manwpower prevented this. Thus by August 1943 the Armoured Corps was organized as follows:

1st Armoured Division (1st Armoured Brigade, 3rd Motor Brigade and divisional troops)
3rd Armoured Division (2nd Armoured Brigade and Divisional troops)
4th Armoured Brigade (1st Tank Battalion, 2/6th, 2/8th and 2/9th Armoured Regiments)
2nd and 3rd Tank Battalion Groups​

Further reductions became necessary during 1943 and 1944, and by 1945 the Australian Armoured Corps had shrunk to 5 armoured regiments and one reconnaissance squadron. At the time there were also the 2/6th, 2/7th and 2/9th Cavalry (Commando) regiments, originally named Divisional Cavalry regiments.

This is the history of Australian tank production in World War II courtesy of Jane's World War II Tanks and Armoured Fighting Vehichles by Leland Ness

A handful of Vickers Medium Tanks had been purchased in the 1930s, but these were worn out by 1939. 10 Light Tanks Mk VIA were ordered in the Spring of 1936 and delivered in late 1937. A follow up order for 24 Light Tanks Mk VIB was placed on their arrival, but this was cancelled shortly after. About 5,000 Universal Carriers were built in Australia 1940-44. These were the only tanks in Australia until March 1942.

According to Ness the General Staff requirement for the AC-1 Sentinel was drawn up in November 1940 and the prototype appeared in January 1942, but only 66 Sentinel tanks were built between August 1942 and the termination of production was terminated in July 1943. 22 were built in 1942 and 44 in 1943. However, the Australians did built 15 LP series armoured cars in 1939, 245 Dingo scout cars 1942-43, 238 Rover light armoured cars 1942-43, and 5,661 Universal Carriers 1940-43.

The loss of the Dutch East Indies in March 1942 resulted in the diversion of 50 M3 light tanks and 148 Marmont-Herrington CTLS light tanks to Australia, which were taken over by the Royal Australian Armoured Corps (RAAC). The CTLS machines were only good for training, but the M3 light tanks complemented 10 that the RAAC had already received from the US for familiarisation, which came from the Australian allocation of British Lend Lease and 315 M3 light tanks (270 in 1942 and 45 in 1943) were received from this source. This source also provided 777 M3 Lee/Grant medium tanks which were delivered between March/April 1942 and the end of that year. The Australians also received British built Matilda infantry tanks which arrived from April 1942 and 304 were on strength by the end of the year and in 1944 they bought New Zealand's 33 Matilda close support tanks.

The source also says that the Americans sent 503 M3A1 scout cars, but does not give the dates. At least 97 British Staghound armoured cars were received in 1944 and the Canadians sent 171 scout cars.

So before March 1942 there are about a dozen tanks in Australia, but by the end of the year they have about 1,500.

 

[NOMISYRRUC]

At the end of 1941 the RAAF had 18 squadrons in the Pacific. 4 were in Malaya, 3 were in New Guinea, 3 were defending Darwin and the other 8 were elsewhere in Australia. Apart from the 2 fighter squadrons in Malaya that were equipped with Buffaloes all the squadrons were either general reconnaissance or army co-operation units equipped with Catalinas, Hudsons or Wirraways. However, they were reinforced by 2 USAAF bombardment groups equipped with B-17s, which were flown from the Philippines to Australia towards the end of December 1941.

The subsequent growth of the RAAF and USAAF in Australia and New Guinea to March 1943 was as follows:

31/03/1942 - 25 RAAF squadrons and 7 USAAF Groups (5 bomber and 2 fighter)
30/06/1942 - 26 RAAF squadrons and 8 USAAF Groups (5 bomber and 3 fighter)
30/09/1942 - 33 RAAF squadrons and 6 USAAF Groups (4 bomber and 2 fighter)
31/12/1942 - 33 RAAF squadrons and 5 USAAF Groups (3 bomber, one fighter and 1 troop carrier)
31/03/1943 - 40 RAAF squadrons and 5 USAAF Groups (2 bomber, one fighter and 2 troop carrier)​

The 25 RAAF squadrons on 31/03/42 included:

5 fighter units (3 Kittyhawk, one Beaufighter and one Wirraway),
2 army co-operation squadrons,
18 G.R. squadrons, one naval co-operation squadron, one Beaufort torpedo bomber squadron and
4 transport squadrons. The 4 squadrons in Malaya had been disbanded by the end of March 1942.​

Therefore the 5 existing fighter squadrons had been formed since January 1942. That is the Wirraway squadron was formed in January and the other 4 were formed in March.

There was a net increase of one squadron in the end of the next quarter. The Wirraway fighter squadron disbanded in April, but the RAAF formed its first bomber squadron in the Pacific on Mitchells in April and No. 1 P.R.U (later No. 87 Squadron) was formed in June.

The increase of 7 squadrons in the third quarter of 1942 was due to the transfer of 3 Spitfire squadrons (one RAF and 2 RAAF) from the UK and the formation of 4 new squadrons. The new units were one Beaufighter long-range fighter, one Beaufort torpedo-bomber, one Anson G.R. and one transport squadron.

No new squadrons were added in the final quarter of 1942. The 7 squadrons added in the first quarter of 1943 comprised 4 fighter units (including the first Boomerang squadron), 2 Anson G.R. squadrons, one Beaufort torpedo-bomber squadron and one transport squadron.

 

[NOMISYRRUC]

A Japanese invasion intended to occupy all of Australia - or at least the major population centres on the eastern seaboard - would have been disastrous . . . for the Japanese. Australia would have been able to meet any invasion on the east coast with two corps of AIF and militia divisions - including armour - and with a US Army corps that was on its way by mid-42. Britain would ship forces to assist because it would be too much of a loss of face not to do so. The logistics massively favour Australia. The numbers would soon favour Australia.

It depends upon when the invasion is. If it was attempted at the end of 1942 I agree. If it was the middle of 1942 the Japanese stand a good chance of success. That is subject to the men and merchant shipping being available, which IOTL weren't.

 

[NOMISYRRUC]

Every Japanese ship sunk, aircraft downed and soldier killed is one less they will have to defend their earlier conquests and their own territory later in the war.

Here I think the Japanese are swapping the OTL losses at Midway, New Guinea and Guadalcanal in 1942 for the same losses in TTL's Australian Campaign. Therefore it makes no long term difference if the campaign fails.

 

[Fred the Great]

This topic has come up several times and I still have some of the notes on my laptop. . . snipped

December 1941 is, of course, rather irrelevant, while first quarter 1942 isn't much better. It's kind of hard to say when an invasion would be most likely, but I would think not before the beginning of the third quarter (July) at the earliest. By which time, Australian and US forces in Australia are rather different.

To give some idea, on 18 April 1942, there were - in terms of Allied ground forces under MacArthur (through Blamey) - 38,000 Americans, 104,000 AIF and 265,000 militia. Blamey's reorganisation of Australian Military Forces had taken effect on this date. Under him, there were two armies, plus a corps (Bennett in WA), and the Northern Territory and New Guinea forces. In total, and not including the latter forces, which were basically the equivalent of a division respectively, Blamey had 10 Australian divisions, plus the 41st Division of the US Army (based in Melbourne until July).

As of the above date, First Army (covering NSW and Qld) had seven divisions organised in to two corps. The leading formation was the experienced 7th Division, which could be considered "elite" compared to practically anything the Allies had in the Pacific Theatre in that time. In addition, Blamey had the 1st Armoured Division in reserve, which actually had 142 tanks about this time of various types (mostly M3 Light and M3 Medium). In addition, there were garrison troops across the country.

Now, I know you're just repeating a myth in your description of the militia ("incompetently trained and organised") but let's address it. There has long been - and certainly was then - a stigma against conscripts in Australia due to our exalting the virtues of the volunteers who served overseas. But why would Australia's militia divisions be any different - by virtue of being conscripts - than British and American divisions?

For example, the 41st Division, US Army was a National Guard outfit that, while called up for full-time service about September 1940, was under equipped and certainly under trained even for a time after arrival in Australia. The Australian militia divisions were called up from the beginning of the war for long periods of training, and immediately following the outbreak of war with Japan, a number of Second Australian Imperial Force officers were recalled and given commands in the militia.

In terms of equipment shortfalls, Australian industry was delivering in key areas. For example, the Army said it had a shortfall of 32,000 rifles in February but these were being produced at the rate of 8000 a month. The ubiquitous 24-pounder was also being produced in good numbers and, in terms of artillery, every one of those 10 Australian divisions had more guns than the 41st Division.

Just to add some information to all of this, one interesting tidbit is that when Australia was pressuring Churchill for the return of the 9th Division - the one Montgomery later wished he could have had for D-Day - the British PM stated in writing that one of his armoured divisions was on its way around the Cape in April-May and should the Japanese land in force it would be diverted to Australia. There simply is no doubt the Brits would have sent forces to Australia in the event of Japanese invasion.

Every month that ticks by you have the Australian and American forces getting stronger with more men, but, more importantly, more equipment and the benefits of more training and more experience from returned 2nd AIF officers and men. Just from an American perspective, by mid-May, the 32nd Division was in Australia, and in August the headquarters of I Corps had arrived.

 

[Fred the Great]

It depends upon when the invasion is. If it was attempted at the end of 1942 I agree. If it was the middle of 1942 the Japanese stand a good chance of success. That is subject to the men and merchant shipping being available, which IOTL weren't.

See my longer post above. They certainly did not stand a good chance of success by the middle of 1942. Whatever they landed would have been bogged down and ultimately either forced to withdraw or lost.

Here I think the Japanese are swapping the OTL losses at Midway, New Guinea and Guadalcanal in 1942 for the same losses in TTL's Australian Campaign. Therefore it makes no long term difference if the campaign fails.

Um, yeah, it would, because the losses would be across the board, not just to the IJN but to the IJA and to Japan's merchant fleet. Also, without those campaigns, the Americans have more to contribute.

 

[NOMISYRRUC]

Now, I know you're just repeating a myth in your description of the militia ("incompetently trained and organised") but let's address it. There has long been - and certainly was then - a stigma against conscripts in Australia due to our exalting the virtues of the volunteers who served overseas. But why would Australia's militia divisions be any different - by virtue of being conscripts - than British and American divisions?

It may be a myth, but I was quoting the Australian Encyclopaedia entry.