Reading Parshall, I wonder the same thing he did: WI Yamamoto hadn't (quite) got his way, & the "decisive battle" had been provoked by a more-powerful force trying to invade Moresby?
Does Nimitz get word before Enterprise & Hornet sortie for the Doolittle Stunt?
IIRC, Hypo had figured out Coral Sea was coming before that, & it only caused trouble for ID of AF later.Difficult to say. In March there was a routine change in key setting for what the US referred to as the JN 25 code. That shut the USN out of the operational planning traffic until after the Tokyo raid in April.
That may have been how...As it was the US take on Japanese actions in the S PAC in April/May derived from other signal & general Intel sources.
I don't recall hearing that before. I don't doubt it; IJN signal security strikes me as pretty bad, & their troubles with distributing the codebooks, which helped crack JN-25 for the Midway reads, didn't help.The Tokyo raid triggered a lot of radio traffic with sloppy security. This helped break the new encryption key of the JN25
IIRC, Hypo had figured out Coral Sea was coming before that, & it only caused trouble for ID of AF later.
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Me, neither. AFAIK, the movement cypher (& I may have the timing on that wrong) & J-19 were being read clear pretty regularly, but not JN-25, not til quite a bit later. My point is, even without being able to read JN-25, there would be a notion something big was in the works. As I recall from Holmes, that was true, & for this scenario, that's enough; I don't recall when that happened, & that's key.HYPO & the others worked off multiple radio sources, Signal analysis was important. I don't know how many other codes were penetrated by the US in 1942. Not found a broad account of this for the. US.
I believe it. That may have been the one good thing to come out of it.When the bomber were sighted over Japan HQ Home Fleet went crazy. And burnt up the airwaves trying to mount a effective search/interdiction of the enemy the picket ship/s had reported, or anything else out there. Radio discipline broke down in the heat of the moment.
I believe it. That may have been the one good thing to come out of it.
You mean bait them into a *Midway op?The home fleet burnt off a lot of fuel in their flail ex. Had the USN understood that aspect clearly they could have run the IJN out of gas with more of the same.