AHC/WI: Japan takes Ceylon

[Magnum]

Assume for a moment that, on account of different scheduling, all 3 US carriers - Lexington, Saratoga and Enterprise - are at Pearl Harbor on Dec. 7th and are all blown up, in addition to the OTL losses. Otherwise there's just no way to make this work.

Given this, what would be needed in order for the Japanese to successfully invade Ceylon around the time of the OTL Indian Ocean Raid, before the British reinforced the island? At first glance, I would say their operation against Papua New Guinea, and maybe even the Solomons, absolutely has to go, in order to free up the required shipping, but also manpower. Moreover, another bit that would help a lot would be managing to trap the British force that was withdrawing from Rangoon, freeing up even more troops. Also imperative would be actually dealing a significant blow to the British Eastern Fleet, including sinking all three carriers instead of just one. Is this enough, or is more needed?

More importantly to this thread though - what can Japan potentially achieve in the near term through a conquest of Ceylon? How would India be affected (in more ways than one)? Is this a better short-term alternative compared to pushing against Australia in Papua New Guinea and the Solomon Islands?

(Japanese defeat is inevitable given US production, so let's not bog down discussion on whether japan can win the war through this, cos' it can't )

 

[Just Leo]

There's a question. What could Japan potentially achieve through the conquest of Ceylon, as opposed to what was achieved by the Easter raid. At least until 1944, the answer is largely nothing, and what assets and logistical supplies they possess are required in establishing a much closer perimeter with the conquest of New Guinea and the Solomons.

 

[Shinsu]

I do not think that Japan would have the amphibious tonnage (let alone manpower) to perform such a task during your time-frame. 90% of the tonnage and half of the ground troops were earmarked for Malaya and the Philippines. The Malayan campaign would have ended just one month before the raid and the Philippines didn't end until two months after. These two fronts would be where you'd really get the manpower from. The Navy had around 100,000 tons left after the allocation but that was barely enough to land and support a reinforced regiment.

The Japanese defensive strategy was to have fortified positions along it's conquests which would include strong-points needed in the south pacific in the Solomons. Leaving Papau New Guinea un-occupied is a danger to their supply lanes (which is why the Philippines were attacked) and acts as an open gate-way to the most important part of their conquests so a change in strategy would also need to occur.

The Japanese had the 55th regimental group tasked with conquering wake, the bismarks, guam, new guinea and the gilbert islands. I can't find any accurate numbers of the count of troops within the group but you could get some manpower and tonnage if you want to get them to Ceylon. The invasion of the minor islands was to prevent them from causing any problems in the future but it is possible that most could be over-looked. My best guesses (with New Guinea still being attacked) would be 7,000 troops at max for the invasion. That does not mean that they have the shipping required to support these troops however.

Ceylon would be far away from any of the front lines. The closet that the Japanese got was when they invaded Manipur around the Burmese border and that wasn't until 1943. Azar Hind was the Japanese puppet government for occupied Indian land but it's controlled land was extremely small and his control was in place really only through the Japanese. The further that they get into India, the less problematic and more logical an invasion of the island would be. But trying to get them further into India by any significant margin for a long period of time is rather ASB. They didn't have the infrastructure, manpower, or naval power to go far in.

It honestly would have been an utter failure. They couldn't pull off the raid with as many ships because some would be needed to guard the transports as they made the very long journey across enemy waters towards the shore. Reinforcement would be very difficult for the Japanese and rather easy for the British and Indians since the distance between the mainland is small for them. The Japanese would have no way to resupply the troops even if they do end up landing on the island. Finally, what benefit would they get from capturing a location so far from the fronts?

 

[hipper]

occupying Ceylom could win the war if they can dominate the Indian Ocean they could stop supply convoys to the British in North Africa and India as well as preventing lend lease to the Soviets via Iran.

That could enable Germany to defeat the Soviet Union - a long shot but the best chance the axis had.

That changes the war.

 

[sloreck]

They can't close the Indian Ocean to the shores of Africa from Ceylon. Assuming the Japanese take it, it is waaay out there logistically. The biggest issue is petroleum products. Every tanker you send to Ceylon is one less going to Japan or the Pacific and Japan does not have enough tankers before they begin being sunk. Aircraft in Ceylon have a limited strike range, certainly convoys along east Africa to Suez or those going to the Persian Gulf/Persia for oil or delivering LL are out of range. A Japanese anti-shipping campaign by subs is possible, but they don't do that and they don't have the subs to spare from their requirements elsewhere.

Japan taking Ceylon is a nuisance for the Allies, but for the Japanese takes resources away from where they are really needed and gains very little. It most assuredly does not change the war in any fundamental way.

 

[CalBear]

Beyond the fact that they can't possibly do it?

Just as the attack on Pearl Harbor was a RAID, the incursion into the IO was a RAID. There is a world of difference between conducting a raid and mounting an invasion and even more of a difference between mounting an invasion and supplying/supporting a military force. It is 1,600 miles from Singapore to Ceylon. That is 50% further than IJN ever attempted a landing (Java was mounted out of Cam Ranh Bay & Jolo Island (Sulu Sea) and it was done with two divisions. Ceylon covers 25,000 SQUARE MILES. You don't take an area of that size with two divisions.

British forces can reinforce across a strait 32 miles wide. The Japanese need to cover nearly the distance between Newfoundland and Ireland.

The Japanese never had sufficient force to mount an invasion, much less maintain a force in those circumstances. The United States couldn't have done it before mid 1944, maybe late 1944-early 1945.

 

[hipper]

They can't close the Indian Ocean to the shores of Africa from Ceylon. Assuming the Japanese take it, it is waaay out there logistically. The biggest issue is petroleum products. Every tanker you send to Ceylon is one less going to Japan or the Pacific and Japan does not have enough tankers before they begin being sunk. Aircraft in Ceylon have a limited strike range, certainly convoys along east Africa to Suez or those going to the Persian Gulf/Persia for oil or delivering LL are out of range. A Japanese anti-shipping campaign by subs is possible, but they don't do that and they don't have the subs to spare from their requirements elsewhere.

Japan taking Ceylon is a nuisance for the Allies, but for the Japanese takes resources away from where they are really needed and gains very little. It most assuredly does not change the war in any fundamental way.

The worst losses the Japanese took was when American Carrier aircraft attacked their convoys if the KB get within range of a Winston Special the political fallout could be catastrophic. Certainly convoys could be suspended. if this happened at the same time as Rommel was dashing to El Alamein the butterflies could be huge.

The Tanker usage is the same if you are steaming in the Coral sea or Indian Ocean, both are pretty far from Japan.
a base on Celoyn could make each Convoy to Egypt a battle and prevent the flow of Lend lease to Russia. Both have significant positive effects for the Axis powers

Of course it means Japan has to weaken its position in the Pacific so it's unlikely. it is the worst option for the allies however.

 

[King Augeas]

More importantly to this thread though - what can Japan potentially achieve in the near term through a conquest of Ceylon? How would India be affected (in more ways than one)?

Japan can't conquer the entire island, it's too big for the limited number of troops available. But let's say that Japan lands there, captures an airfield, neutralises the naval base and establishes a defensible perimeter.

But then what? They can't interdict the shipping routes to North Africa, as it's 1900 miles to the Horn of Africa, while the convoy routes can be covered by the British bases in Aden, East Africa and, from May, Madagascar. You'd need to lurch forward another 700 miles to the Maldives, and then another 1300 miles to the Seychelles, and even then the African coast is still 600 miles away!

Nor can Japan reliably interdict the route to India, as I believe most convoys loaded and unloaded at Bombay and use rail thereafter, rather than sail around to Calcutta, and these incoming convoys can easily be covered by land-based air. And Bombay is 1000 miles from Colombo.

 

[hipper]

Beyond the fact that they can't possibly do it?

Just as the attack on Pearl Harbor was a RAID, the incursion into the IO was a RAID. There is a world of difference between conducting a raid and mounting an invasion and even more of a difference between mounting an invasion and supplying/supporting a military force. It is 1,600 miles from Singapore to Ceylon. That is 50% further than IJN ever attempted a landing (Java was mounted out of Cam Ranh Bay & Jolo Island (Sulu Sea) and it was done with two divisions. Ceylon covers 25,000 SQUARE MILES. You don't take an area of that size with two divisions.

British forces can reinforce across a strait 32 miles wide. The Japanese need to cover nearly the distance between Newfoundland and Ireland.

The Japanese never had sufficient force to mount an invasion, much less maintain a force in those circumstances. The United States couldn't have done it before mid 1944, maybe late 1944-early 1945.

Java is Bigger than Ceylon. The Pacific theatre was Huge, you won by having more troops and support than the opposition.

there was one Indian division, two Australian Brigades and an East African brigade on Celyon at the time of the Historic raid.

The Japanese had taken on worse odds in Malaya and succeeded.


they have the amphibious lift with the required range it's just a matter of more steaming.

and if they did not invade Burma they have the troops

The difficulties would be in Maintaining the KB offshore while the invasion happened,

they might have to split their force into 2 and theorise that each half would be superior to the RN in Indian waters.

And early reinforcement of airfields with land based aircraft a vital necessity.

Given Historical results the British would not be able to challenge the Japanese successfully in the air untill 1943
once the Japanese have air superiority British forces would be reduced to running supplies in overnight to resuply.

I'm Not arguing that the result is a foregone conclusion for the Japanese, it's a risk. It has however the possibility of a bigger payoff than anything else they could do in the second quarter of 1942.

Supply is a weak point but if the RN could be suckered into a Major battle in Defense of Celyon then the Japanese would have a free run for a while.

Regards

Hipper.

 

[hipper]

Japan can't conquer the entire island, it's too big for the limited number of troops available. But let's say that Japan lands there, captures an airfield, neutralises the naval base and establishes a defensible perimeter.

But then what? They can't interdict the shipping routes to North Africa, as it's 1900 miles to the Horn of Africa, while the convoy routes can be covered by the British bases in Aden, East Africa and, from May, Madagascar. You'd need to lurch forward another 700 miles to the Maldives, and then another 1300 miles to the Seychelles, and even then the African coast is still 600 miles away!

Nor can Japan reliably interdict the route to India, as I believe most convoys loaded and unloaded at Bombay and use rail thereafter, rather than sail around to Calcutta, and these incoming convoys can easily be covered by land-based air. And Bombay is 1000 miles from Colombo.

They could make a forward base for carriers and dominate the Indian Ocean, if the RN had been defeated in battle while defending Ceylon.
If the Japanese fleet can use the Indian Ocean without challenge then it's too risky for the allies to put convoys through it in the numbers required.

Celoyn is not too big to capture with two divisions. it's too big to defend with two divisions. If however the Japanese have command of the sea and air, they don't need troops to defend it, they just need troops to occupy it.

Once the Japanese have captured Columbo and Trincolmalee any other British forces can rot in the Jungle.

 

[sloreck]

"if they don't invade Burma..." That's the thing here. In every "Japan does this instead of that" scenario this choice has to be made. Unlike the USA which can do more as the war goes on because of its industrial and human capacity, Japan's resources are marginal at best on day one of the war and they can never keep up with losses let alone get ahead of where they were on day one. Trading Burma for (part of) Ceylon is much better for the Allies. Remember one of the motivations for going in to Burma was to cut the Burma Road and the supply line to China, trade Burma for Ceylon and that doesn't happen. There is no threat to India. Keeping major Japanese naval forces in the Malaya/Ceylon area exposes them to land based air from Southern India and Burma. It allows the Allies to threaten Thailand.

The USA could devote resources to taking islands that they could have avoided (think Pelileu) or campaigns extended beyond need (think totally cleaning out Japanese from New Guinea - the forces left on the western end were impotent) because they were so resource rich. Japan, OTOH had zero (actually less than zero) spare forces or margin for error.

 

[Catspoke]

"It has however the possibility of a bigger payoff than anything else they could do in the second quarter of 1942." Of course maybe doing little is the best thing.

Perhaps the best thing to do is to continue to do merchant raids like Indian Ocean April 42, where you are only risking a light carrier, submarine and cruiser force (a Shoho class carrier would seem like a great commerce raider paired with a Tone class cruiser). Meanwhile keeping the 6 fleet carriers safely in port. Try to increment the Allied shipping losses to the point that they Allies can do less stuff in 1942.

In the viewpoint of 1942, it probably not unrealistic for the Japanese to hope that the German beat the Soviets, or at least make peace with them and then with the Germans free to engage the USA and Britain in the Atlantic and the Med and all her fleet carrier still intact to defend the ring that the Japanese wouldn't have to deal with counter invasions for quite some time.

Midway or even Ceylon hardly seem worth the risk/reward involved.

 

[catalfalque]

Japan taking Ceylon would have a major effect in India. Don't forget Bose was no minor figure. India has been on the verge all throughout the 1930s, the rush to independence in the 1940s after the war was no complete surprise. India is not a happy fluffy land, but its being kept loyal by there being no other choice. Japan in Ceylon, especially one talking up Co-Prosperity Sphere, and not losing Midway, is going to have a massive effect within India.

 

[Just a Rube]

The difficulties would be in Maintaining the KB offshore while the invasion happened,

they might have to split their force into 2 and theorise that each half would be superior to the RN in Indian waters.

And early reinforcement of airfields with land based aircraft a vital necessity.

Given Historical results the British would not be able to challenge the Japanese successfully in the air untill 1943
once the Japanese have air superiority British forces would be reduced to running supplies in overnight to resuply.

I'm Not arguing that the result is a foregone conclusion for the Japanese, it's a risk. It has however the possibility of a bigger payoff than anything else they could do in the second quarter of 1942.

Supply is a weak point but if the RN could be suckered into a Major battle in Defense of Celyon then the Japanese would have a free run for a while.

Regards

Hipper.

Ignoring the differences between an invasion of Java and one of Ceylon, and focusing on just this point.

The British absolutely would have air superiority very quickly. They have India as an unsinkable aircraft carrier, and can easily resupply as needed. There is no need to discuss the RN; they can and will throw as much land-based air at the problem as they need, something which is vastly easier when you are operating out of India with all its rail links than when you are relying on naval transport through hostile waters.

The Japanese, on the other hand, have whatever they can ship over (and if the British manage to wreck the port facilities before they are defeated, then the Japanese are essentially hosed from the get-go), while being constantly exposed to attacks on their resupply convoys. Meanwhile they are burning the fuel they can't afford, and losing men in a sinkhole vastly worse than the Guadalcanal Campaign ever was. The attrition equation, just in aircraft alone, is not remotely in their favor, something the Japanese were keenly aware of.

The whole point of the Indian Ocean Raid was to attack quickly, taking advantage of mobility, surprise, and the superior quality of Japanese naval aviation. An attempt to seize and hold Ceylon surrenders the first two (as even a quick campaign will take months), and allows the British to concentrate the forces they need to overcome the last with sheer numbers. And as you note, if the KB is tied up in Ceylon, it's not supporting other actions, which means the Allies get much more of a free reign in the Pacific.

 

[Just Leo]

The only purpose that could be served by an invasion and occupation of Ceylon is as a prelude to Operation Ashika. All other goals were achieved by a simple raid. British forces, with advanced intelligence, and a hero in a PBY, cannot prevent or interfere with an aerial assault, and the British fleet runs away. What cannot run is destroyed. A British bomber force is met with great incompetence on behalf of the Japanese, but the British are found to possess even greater incompetence in their attack, so that's a wash. The Japanese can safely return to the war as it matters, and attempt to deal with Americans operating from Australian and Hawaiian bases, confident that they will not be interrupted.

 

[hipper]

The only purpose that could be served by an invasion and occupation of Ceylon is as a prelude to Operation Ashika. All other goals were achieved by a simple raid. British forces, with advanced intelligence, and a hero in a PBY, cannot prevent or interfere with an aerial assault, and the British fleet runs away. What cannot run is destroyed. A British bomber force is met with great incompetence on behalf of the Japanese, but the British are found to possess even greater incompetence in their attack, so that's a wash. The Japanese can safely return to the war as it matters, and attempt to deal with Americans operating from Australian and Hawaiian bases, confident that they will not be interrupted.

You do have to assign ASB levels of co operation between the Japanese and German high commands for an invasion to work but Central Russia is more desicive to the war than the Pacific Theater. Something the British realised when they prioritised supplies for Russia over supplies for Malaya

All that is requires is for the Japanese to make that intuitive leap and base the KB n the Indian Ocean untill 1944 when the Americans are too strong to be ignored.

Stopping lend lease supplies to Russai is a bigger Axis Gain than anything they could win in the Pacific. It the Americans do concentrate for an invasion of somewhere vital in 1943 The KB can move but the Indian Ocean is the Critical theatre for Russian supplies.

( you also have to stop Russian flagged merchantman saying to America ) but that's a political decision which takes no extra forces only the possibility of Russian reaction which is mild by 1942.

 

[Just Leo]

You do have to assign ASB levels of co operation between the Japanese and German high commands for an invasion to work but Central Russia is more desicive to the war than the Pacific Theater. Something the British realised when they prioritised supplies for Russia over supplies for Malaya

All that is requires is for the Japanese to make that intuitive leap and base the KB n the Indian Ocean untill 1944 when the Americans are too strong to be ignored.

Stopping lend lease supplies to Russai is a bigger Axis Gain than anything they could win in the Pacific. It the Americans do concentrate for an invasion of somewhere vital in 1943 The KB can move but the Indian Ocean is the Critical theatre for Russian supplies.

( you also have to stop Russian flagged merchantman saying to America ) but that's a political decision which takes no extra forces only the possibility of Russian reaction which is mild by 1942.

Since the Japanese did nothing to impair the shipment of goods from America to the port of Vladivostok, through Japanese-controlled waters, it hardly seems worth the effort.

 

[hipper]

Since the Japanese did nothing to impair the shipment of goods from America to the port of Vladivostok, through Japanese-controlled waters, it hardly seems worth the effort.

yes it takes a near ASB level shift in mindset from Japan acting in its perceived best interest and its actual best interest.
Germany victorious in Russia means fewer Americans attacking Japan in 1944.

Interdicting supplies going to Russia is the only way Japan can change how much effort America expends against Japan.
Reducing the American Effort is the only way they can improve their situation in the war.

The logic is simple.

Changing attitudes is much Harder.

 

[Johnrankins]

Except as everyone from CalBear on down has said taking and holding Ceylon is logistically impossible. The Japanese could no more take and hold Ceylon as they could take and hold the Moon. It is way too far away for them and while they are wasting time, money and manpower on that they aren't using it trying to stop the US from invading one island after another. If Japan tries taking Ceylon they lose quicker.

 

[Just Leo]

The logic is simple.

Changing attitudes is much Harder.

How does math fit in? I'm talking simple math, like how many troops, how many ships and how much fuel. It looks like those Japanese who decided war stuff skipped school for logic and math, and went out to play with bayonets instead.