What does Japan do if there are no airfields to conquer?

HJ Tulp

Donor
Reading up on the Japanese invasion of South East Asia what strikes me is that the East Indian archipelago was apparently dotted by airfields. The Dutch idea was that bombers operating from these airfields could defend the East Indies against Japanese. The opposite was the effect though. The bombers only caused minor damages to the Japanese invasion fleets which pretty easily conquered the badly defended airfields.

The captured airfields allowed the IJN to make it's landings under the cover of land-based aircraft. Time and time again ABDAs Combined Strike Force was discovered and attacked by airplanes operating from those captured airfields. It seems to me that the balance of those airfields was very much in the negative for the Netherlands and ABDA.

Let's say that the Netherlands don't build airfields outside of Java or thoroughly destroy them at the start of the war. What do the Japanese do? I personally see three options:

  1. The Japanes advance to the edge of their aircover-range and build an airfield there. When it's finished the repeat the process. The major downside to this is that it costs a lot of time. One source I have read is that it cost the Japanese 70 days to build an airfield. The operations in the DEI were advanced with 30 days because the progress in Malaya was better than expected so there is some room in the plans but it's not much if Japan had to advance and build airfields in three steps.
  2. The Japanese advance only through the OTL western prong via Malaya and its airfields. This requires much fewer (or no) airfield building. This does mean there can only be a attack on Java from the west though. It also means that the allies can reinforce the rest of the Malay barrier at will.
  3. The Japanese forego their doctrine of land-based airsupport and use their carriers to provide the landing fleets with aircover. If the IJN does this will they follow the same steps as OTL? If they don't need the airfields they could also just go directly for Java. Of course the big problem for the Japanese is that this will mean they cannot use their carriers for other operations.

I would love to hear what you guys think of this :)
 
The DEI defense concept was to build airfields across the islands and mass aircraft at these airfields when necessary to strike attacking forces. Unfortunately, the DEI never got enough aircraft to make the concept feasible, also the quality of what they had wasn't the greatest either.
The Japanese were notoriously slow at building airfields, not sure of their average time but it was definitely much slower than achieved by the US Seabees. The overall lack of mechanization in Japan I'm sure was a key factor.

Until the USN Central Pacific amphibious offensives, everyone believed that amphibious operations required land-based air support to be successful. No one believed that aircraft carriers and their planes could provide the necessary support for the operation to be successful.
Observations/comments on your options:
1. Slows down the Japanese advance dramatically as you say. Aircraft and troops were being rushed into the DEI from the US and Australia; if the Japanese advance is slower, there is good chance that Java could offer a much better defense. I think Java would still fall but it would take a month or two to completely occupy.
2. Actually, Malaya gives the Japanese excellent access to the central islands of the DEI and by virtue of its locations cuts off Sumatra from the rest of the DEI. The Japanese could advance along two axes, one from the west through Sumatra then to western Java while the second advance goes through Borneo, to Celebes and then Ceram. From these locations, Japanese aircraft could monitor and control access through the various straits in the archipelago. The Allies could not be sure which is the main access of advance.
3. The Japanese occasionally used an aircraft carrier to provide air support until an airfield could be captured and make functional. Except for the aberration of Midway, there was never any intention to use the Main Striking Force to provide long-term air support for an amphibious operation; it just wasn't envisioned as its role.
The US was forced to use aircraft carriers to provide air support during the Central Pacific offensive because there wasn't any other option. But by that time, the USN was getting a veritable flood of aircraft carriers so that it could allocate carriers to provide relatively long-term air support for an amphibious operation yet continue offensive operations elsewhere.
 
Might force the Japanese into organizing better construction groups for building airfields. Earlier they might make a decision for more amphibian aircraft. The IJN did fly a amphibian version of the A6M Zero. Provide those a bit earlier. And they'd at least have to consider using their carriers for a bit more support of the littoral operations.

There is also that since the Dutch were so poorly prepared to use airpower the Japanese did not need as much as they used OTL. The campaign would have been mostly ground and surface ship operations, with token air participation.
 

HJ Tulp

Donor
Thanks for your response @Gunner's_Quadrant !

Actually, Malaya gives the Japanese excellent access to the central islands of the DEI and by virtue of its locations cuts off Sumatra from the rest of the DEI.

Would the Malaya airbases enable Japanese airsupriority in Strait Makasar on the other side of Borneo?


The Japanese could advance along two axes, one from the west through Sumatra then to western Java while the second advance goes through Borneo, to Celebes and then Ceram. From these locations, Japanese aircraft could monitor and control access through the various straits in the archipelago. The Allies could not be sure which is the main access of advance.

So basically like OTL but without a advance through the Molucas to Timor?

3. The Japanese occasionally used an aircraft carrier to provide air support until an airfield could be captured and make functional. Except for the aberration of Midway, there was never any intention to use the Main Striking Force to provide long-term air support for an amphibious operation; it just wasn't envisioned as its role.
The US was forced to use aircraft carriers to provide air support during the Central Pacific offensive because there wasn't any other option. But by that time, the USN was getting a veritable flood of aircraft carriers so that it could allocate carriers to provide relatively long-term air support for an amphibious operation yet continue offensive operations elsewhere.

I'll think on this.
 

HJ Tulp

Donor
Might force the Japanese into organizing better construction groups for building airfields.

Any idea how fast they could theoretically be able to build a airfield?

Earlier they might make a decision for more amphibian aircraft. The IJN did fly a amphibian version of the A6M Zero. Provide those a bit earlier. And they'd at least have to consider using their carriers for a bit more support of the littoral operations.

How was the performance of Japanese amphibian fighters compared to the Allied opposition?

There is also that since the Dutch were so poorly prepared to use airpower the Japanese did not need as much as they used OTL. The campaign would have been mostly ground and surface ship operations, with token air participation.

Indeed, the whole operation in the Southern Resource Area was completed 30 days in advance of the pre-war planning. However, the Japanese can't know that.
 
Been off the net for the past week and just saw this.

How was the performance of Japanese amphibian fighters compared to the Allied opposition?
The Rufe was an excellent fighter aircraft, definitely capable of handling bombers and observation type aircraft. However, the float and outriggers put it a disadvantage against 1st line Wallie fighters; probably would be competitive against a Wirraway, Buffalo, and the like.

Figure an effective range of 200-250 miles for fighters and 500-600 miles for bombers; they can fly further but to ensure optimal coverage that is a good planning factor.
Doubtful that Japanese aircraft can successfully control the Makassar Straits from Singapore, just too far.
 

HJ Tulp

Donor
Been off the net for the past week and just saw this.

Thanks for your response anyway!

The Rufe was an excellent fighter aircraft, definitely capable of handling bombers and observation type aircraft. However, the float and outriggers put it a disadvantage against 1st line Wallie fighters; probably would be competitive against a Wirraway, Buffalo, and the like.

What I see on the web the performance of the Rufe was 20% less than that of the original Zero. It's speed seems a bit less than the Buffalo but it's turning rate might off-set that. Ofcourse at a certain point it would encounter Hurricanes.

There is also the fact that it's first flight wasn't until the 7th of December and it's total production at 327 at the end of the war. Can the Rufe be deployed on time and in sufficient numbers to adequatly cover the eastern invasion route?

Figure an effective range of 200-250 miles for fighters and 500-600 miles for bombers; they can fly further but to ensure optimal coverage that is a good planning factor.
Doubtful that Japanese aircraft can successfully control the Makassar Straits from Singapore, just too far.

There were British airfields near Sarawak. If ATL there are no (usable) airfields in the DEI outside of Java the airfields Japan can control are at Singapore, Sarawak and Davao. I've made 600 mile radius circles from those places:

airbases.PNG


This puts the western invasion route and most of the Java Sea in bomber (but not fighter) range. Regarding the eastern invasion route Makassar Straight is not totally covered but the oil-harbours are. Would the IJN risk the time and lack of fighter cover to go for Balikpapan or Banjarmasin and then take 30-70 days to build a airfield?
 
Top