Looking at the Pacific war of 1942 (especially Midway- again!) from another angle. Historically the fact the US were reading the JN-25 code allowed them to build an accurate image of the japanese intentions, timeframe and forces allocated, and set up an ambush accordingly.
OTL the japanese were planning to change the aforementioned codes, initially slated for April 1st, then postponed to May 1st and finally to May 27th (when it was far too late).
Of course, that is not to say that being locked from reading the JN25 code for a while will mean the US are totally blind, they could derive intelligence from other means. Looking at the map it would be clear that the japanese will further advance into South Pacific (and indeed the USN leadership was fully expecting that), as well as Central (Midway-Hawaii) and Northern areas as well. But without the critical intelligence they obtained OTL, they will need to be on guard in all areas at once (especially South and Central).
So if they don't have the ability to descipher and confirm in time the critical details of japanese plans and intentions in May, how would things have turned out? Would they reinforce Midway as quickly and a much as OTL? Would they still keep TF16 in the South Pacific (and have it actually attack the Ocean-Nauru invasion force rather than feinting and letting themselves be seen then rush for Hawaii) until too late to be available for the Midway defence, and even perhaps King will have his way to get some of the carriers, especially damaged ones (like Yorktown) to commit their aircraft to land bases in the South Pacific? Would the japanese plan unfold exactly as planned with perhaps Yorktown and Saratoga rushing to help Midway on the 6th or 7th only to fall into Yamamoto's trap? Or perhaps they are held in hawaiian waters and let the Midway garrison on it's own? Would the garrison be weaker than OTL, thus making a japanese invasion virtually certain to succeed?
It would be most interesting to see what would be a realistic appraisal of how things would have turned out in this scenario.
OTL the japanese were planning to change the aforementioned codes, initially slated for April 1st, then postponed to May 1st and finally to May 27th (when it was far too late).
Of course, that is not to say that being locked from reading the JN25 code for a while will mean the US are totally blind, they could derive intelligence from other means. Looking at the map it would be clear that the japanese will further advance into South Pacific (and indeed the USN leadership was fully expecting that), as well as Central (Midway-Hawaii) and Northern areas as well. But without the critical intelligence they obtained OTL, they will need to be on guard in all areas at once (especially South and Central).
So if they don't have the ability to descipher and confirm in time the critical details of japanese plans and intentions in May, how would things have turned out? Would they reinforce Midway as quickly and a much as OTL? Would they still keep TF16 in the South Pacific (and have it actually attack the Ocean-Nauru invasion force rather than feinting and letting themselves be seen then rush for Hawaii) until too late to be available for the Midway defence, and even perhaps King will have his way to get some of the carriers, especially damaged ones (like Yorktown) to commit their aircraft to land bases in the South Pacific? Would the japanese plan unfold exactly as planned with perhaps Yorktown and Saratoga rushing to help Midway on the 6th or 7th only to fall into Yamamoto's trap? Or perhaps they are held in hawaiian waters and let the Midway garrison on it's own? Would the garrison be weaker than OTL, thus making a japanese invasion virtually certain to succeed?
It would be most interesting to see what would be a realistic appraisal of how things would have turned out in this scenario.
