A Pacific War reference question- About how many months in advance, did the US anticipate the June 1

Plan Orange 1935. What was not understood clearly until about 1940 was how central the aircraft carriers would be to the actual fighting of the battles.  

That article was written by an amateur who does not know it was the GENERAL BOARD and not the nincompoop, Stark, who shaped the material composition of the fleet.  

Thanks for the article, very interesting an informative.

Discussing this topic on another board, a user helpfully offered more info on the evolution of Allied planning for the anti-Japanese fronts:





My takeaway from this:

The JCS failed to apply the full implications of the shift in Pacific strategy by March 12, 1944 to the full global anti-Japanese war strategy.

From March 12, 1944, the Burma liberation strategy, intended mainly as a way to more efficiently supply China, had become obsolete. It had already been too slow moving, and its future prospects were slow enough, with all the engineering work through the Burmese jungle and mountains, while the prospects for victory in the Marianas, and then destruction of Japanese fleet strength beyond and liberation of the Philippines and establishment of trans-Pacific sea lines of communication (SLOCs) to the China coast were swift enough, that the Burma approach should have been abandoned. Or at least it should have been given no new injections of investment by the Chinese and Americans from their main forces and homeland production centers. The British could press on at their preferred pace as they wished considering its their colony.

From late March, April, May through summer 1944 it would have indeed been more sensible to disengage the substantial Chinese forces, American-trained and otherwise, from the Burma Road reopening passion project of Stilwell and his supporters, and reengaged them in directly opposing the Japanese ICHIGO offensives against southeastern and south central China that were devastating other Chinese Nationalist forces and a wide productive swath of what had remained unoccupied Nationalist Chinese territory for most of the second Sino-Japanese war. The success of the ICHIGO offensives forced the abandonment and destruction of several US B-29 bases and aviation supplies. Any ability to either hold on to these bases and maintain continuity of operations, or even delay their fall and extend operations, would not only have been better for China's 'home game' but better for the Allied air effort, especially as the far more secure Marianas B-29 air bases more thoroughly took over the bulk of the sorties. By this point in the war, with the US naval forces cutting a swathe across the Pacific to the South China Sea by no later than the turn of 1944-45, investing Chinese efforts and forces in denying Japanese takeover of additional Chinese coastal territory or major railways for north-south strategic movement, if at all possible, has more overall strategic value than pushing the relatively isolated Japanese forces in Burma backward.

I have no idea if it was doable from a ground and air and naval and logistics perspective. Would have been quite the shocker for the Japanese though if both Iwo Jima were seized and the IJN stood, and died, in a fight in June 1944 around the Bonins (the Iwo Jima island chain) like that.

Iwo Jima from summer 1944 would have been a great advance base, but I think for the purposes of supplying advanced airfields for supporting massed, continuous air raids on Japan, it would have been insufficient because of its relatively small size for airfield development, so US Marines or Army forces would have still needed to capture some additional real estate inside the Japanese perimeter, either in the Bonins, or within the bypassed Marianas, to stage mass bomber forces, much less ultimately mass ground forces for an eventual invasion.

That makes it sound like a not bad, decent, plan, I could be persuaded of. That said, 30% chance of failing is still a non-trivial risk. And, trying something as audacious any earlier, before the June '44 margin of material superiority had been built up, and the successes of Tarawa, Eniwetok, and the Truk (Chuck) raid achieved, would have been irresponsibly risky, much like the premature audacious Bonins strike that Hector Bywater wrote into his 'Great Pacific War' which he had fail badly, to show that the Americans had to make due with a more methodical, step-by-step advance.

Assuming success at Iwo Jima in June 1944, Spruance could have achieved probable success on three of his four expected follow-on goals:


Could be achieved to a large degree



Could be achieved to a large degree




Just would not work that way- the Japanese could and would easily ferry aircraft down to the Philippines from Japan, Korea and Manchuria by way of the Ryukyus, Taiwan, and China coast, regardless of the situation in the Bonins



Could be achieved to a large degree

Iwo Jima (and other Bonins) give you the blue patrol circle on the right, so yeah a perfect interdiction position against direct air routes between Japan and Micronesia and New Guinea. Japanese aircraft that don't go a really long, roundabout way would have to brave Iwo Jima based patrols.

But the the blue patrol circle on the left, the one that covers southernmost Japan, Okinawa and the other Ryukyus, Shanghai and easternmost China, Taiwan and the northern tip of Luzon, that would force Japan to Philippines flights to take big roundabouts through central China to miss patrols....well, that patrol circle isn't centered on Iwo Jima or the Bonins.  That patrol circle is centered on Okinawa.  So the capture of Okinawa is necessary to establish that big left interdiction circle.

Was Iwo Jima the primary forward staging base for the OTL invasion of Okinawa in OTL? Would it have been adequate on its own? In OTL, I believe US Army and Army Air Corps forces could also flow to Okinawa in substantial #s to Okinawa by the Philippines, which would not be possible to do much earlier without somehow accelerating liberation ops there and its precursors.