ORIGINAL: Lokasenna
I think you're right to hope for the best and just stick to good terrain, defensible places, etc.
Even if he takes Calcutta now, he can't hold it forever. It's a long, lonely sail from Singapore to Calcutta. He'll have some fuel available from Burma, but you'll be able to base out of Trincomalee or Madras (unless he takes those from you to). But basically, if he takes Calcutta - so what? I'm not sure you can stop him (though you should give it the ol' college try), and unless it threatens AV later it's nothing to worry about. It gets him some HI, sure, but I think Warmgr's game is a good example here - njp conquered most of India, but most of that is back in Allied hands by the end of 1942.
I also wouldn't look for him to defend both Calcutta and the South Pacific in major strength, so that gives you some options as well...
My .02.
The defenses of India come in the next few months in strength. GJ knows the OOB, and he may just be trying to take the Calcutta region for the economic benefit in the short term without a push for AV. Of course I cannot rule out AV so I have to attempt a defense with more than what comes to India in the usual reinforcements. I may need to get US ground forces there and fast.
The entire IJN is poised and in good position to rule the IO for some time. I think taking all of India has yet to be done in a PBEM unless I've missed something, but GJ is aggressive and knowledgeable in the area and he loves the dramatic move. I understand his psychology pretty well here and he could want to be the first to do it. He probably would be better off in the long run if he didn't, but that depends on if I can stop him as well.
I do see opportunities in the Pacific, especially No Pac now with all of the CVs occupied and early enough there isn't much else he could have up there.
ORIGINAL: SqzMyLemon
Are the divisions landing at Diamond Harbor ones that were in Singapore? GreyJoy knows that to take India you have to capture Karachi and prevent reinforcements reaching the subcontinent. If the divisions he's landed at DH are from Singapore then I think you can rule out an early attempt at Karachi and the objective is to cut off Allied troops in Burma and benefit from whatever HI, fuel and supply he can gain for 6-8 months. I wouldn't neglect Karachi or Bombay just in case, with the emphasis on Karachi.
It will be interesting to see if he attempts a landing on Ceylon in an effort to secure his flank if the Calcutta region is indeed the objective.
If that invasion fleet comes around Ceylon the first thing I'll do is throw everything now in Madras and Bombay into Karachi. I can't lose it and have any hope here.
If he goes all-in for India I'll have to do something bold as well, it seems. I'll start some units prepping for the Kuriles and Hokkaido now, just in case. Because Singers was such an unusual campaign due to the paradrop and split of the Brit forces, I don't know yet which forces were all there, but there were certaily more than this.
This is the list of what was at Singers during it's fall. Some are here, like the 33rd, 38th and 5th. Some are not yet at least. There are still ship offshore though, likely either waiting to land more units, air groups and/or lots of supply.
[font="Trebuchet MS"]
38th/B Division
33rd Division
15th Ind Engineer Regiment
18th Division
5th Division
38th/A Division
21st Division
1st Tank Regiment
38th/C Division
25th Army
18th Medium Field Artillery Regiment
3rd Medium Field Artillery Regiment
3rd Ind. Mountain Gun Regiment
34th Field AA Battalion
36th Field AA Battalion [/font]
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