ORIGINAL: Canoerebel
I have a vested and ongoing interest in Festung Sumatra, so I don't want to comment in too much detail. "Loose lips sink ships, and all that."
I will say a few things:
1) Some very bright folks have looked at IJ oil needs in Scenario Two and determined that Japan has enough to do without Palembang for a very long time - perhaps deep into 1943.
2) That gives Japan some options in dealing with a Festung Palembang or Festung Sumatra. Nemo's AAR vs. 1 Eyed Jacks has a lengthy and helpful discussion.
3) Either Festung gambit can be handled by Japan as long as the Japanese player attends to it reasonbly quickly. One important item is to take and build some bases that give Japanese strike aircraft a decent shot at controlling entry into available Allied ports.
4) The Allies are pretty much limited to "local/regional" units for the first four to eight weeks - Dutch units and some Commonwealth units from Singapore and perhaps a few from India. That isn't enough to create a fortress that can withstand a well-organized and thought out IJ assault.
Bottom Line: IJ players must pay attention to this region early in the game and make sure they have control of the ports by the end of December or early January. Do that and the Allied player isn't going to accomplish anything meaningful. A very, very clever and experienced IJ player can string things out much further, though, in hopes that the Allied player will stick his neck in the noose. The IJ player will then make moves that will result in the Allied player hanging himself.
Allow me to reply to your points invidually.
1. According to my calculations based on usage rates from the last 6 months, I will be out of oil by mid-1943. Fuel will run out approximately 2-3 months later. Obviously, as fuel becomes scarce, my naval units will be parked and only those vessels needed to bring what little fuel and oil to the HI will be at sea. HI will shut down soon thereafter. The bottom line is that the loss of Palembang to the Japanese player is a game killer regardless of when it occurs. To never have captured it just ensures that the game will never see 1944 regardless og how careful or clever the Japanese player is.
2. I haven't read this AAR so I can not comment on it.
3. I would agree that the Japanese player would have to react very quickly to forestall any allied attempt at fortress building in Sumatra. But I believe that would mean abandoning any historical pretense and would certainly raise a howl amongst most AFBs if Japan made a dash for Palembang on day one. That is why I mentioned the possibility of a house rule or some other means of controlling it. It certainly would mean foregoing any concerted effort to take Malaya or the PI simultaneously which has serious drawbacks of its own for the Japanese player.
And as you mentioned, the Japanese player needs airbases nearby to interdict allied shipping if he is to control allied ports on Sumatra. To do that, he needs to take bases in western Borneo and/or Java. Its highly doubtful that the Japanese will have progressed far enough down the Malaya peninsula to make use of its airfields against Palembang. Even if they have, all the allied player need do is park some AKs in Singapore harbor and put a CAP over them and Japanese bombers will be drawn to them like a moth to flame. Even airfields in northwestern Borneo are unsuitable for the same reason.
So that leaves the airfields on Java. In most cases, the Japanese player is still fighting heavily in the PI and must wait for those forces to become available to take airfields in Java. He can't bypass the PI as that would leave sigificant air forces in his rear. Plus he has to take Tarakan and Balikpapn on the way or risk the same thing. He could forego any operations in the central Pacific but the number of forces that would free up is pretty small and it certainly would allow Australian forces a chance to build up Rabaul and the Solomons.
Then there is the problem of finding the aircraft to conduct the raids. Bettys and Nells are useless without torpedo equipped HQs and most of the Val and Kate units are restricted to the home islands. Idas, Marys and Sonias will barely dent a row boat let alone hit them. Plus the Japanese start the game with only 1000 fighters. Seems like a large number until you consider that the IJAAF has 630 fighters to start the war but only 100 of them are Oscars or Tojos. The rest are Nates and most of those are permanently restricted to the home islands or Manchuria. The same with the IJNAF though most of their 370 fighters are Zeros. Still 8 of 22 units fly the Claude.
4. The problem here is that no Japanese player is going to be able to conduct a well thought out and organized assault against Sumatra in the first 4-8 weeks. You say that they are limited to local/regional units. Are you including combat units that come from Java? Troops from Singapore are easily dispatched across the strait by ship and there isn't much the Japanese can do about it so long as the RAF remains a force in Malaya? All the allied player needs is 400+ AV and level 4 forts. The Japanese player will never be able to get 2:1 odds without stripping everything not tied down. And if those forts are in Palembang, the Japanese player is doomed anyways.
Bottom Line: IJ players must pay attention to this region early in the game and make sure they have control of the ports by the end of December or early January. Do that and the Allied player isn't going to accomplish anything meaningful.
The Japanese player can't stop a Sir Robin into Sumatra. Between ships and air transport, an allied player can get quite a force into Sumtra before the Japanese player knew what happened.
Control of Sumatran ports such as Oosthaven by the end of December? To control these ports means to take them. To do otherwise is to watch an allied player whittle down your air forces trying to keep them closed.
And to take them so early means employing a direct line of advance to northern Java and southern Sumatra from Indochina and Taiwan. It means forgoing any significant attacks on Malaya or the PI. Fail to take the PI and your lines of communication are cut. Fail to invade Malaya and you end up with a fortified Malaya that will prevent any oil from getting through with the added bonus of strong air forces flying in from Burma to bomb Palembang into rubble.
The tone of this is a bit harsher than I intended but it is late and I have to get up early so I'm sorry if the tone offends or angers. I do not mean to do so.
Chez