Yea, read a synopsis, not worth reading.
Look back at the timeline I have posted in here already. Japan was well on the way to their attack long before the US embargos even started. They started their war plans over 7 months before the attack, and was staging life fire exercises with new equipment needed for the attack over 6 months before the first embargo. War was coming, no matter what the US did.
And we know war was coming. That book mentions MAGIC, that is one of the reasons we knew. That is why our 2 active carriers in the theater were working constantly (along with the rest of the fleet) to send planes, supplies, and equipment to our Pacific Islands. The 4th Marine Regiment had been in China for over 25 years, but the threat of war coming and the realization that they would be quickly eliminated and outside of supply in China was why in November 1941 they were moved to the Philippines.
However, nowhere did the Japanese ever leak actual "operational intelligence". In a few instances we had code words, but did not know their meaning. We knew something was coming, and all expectations were that it was going to hit the Philippines, Wake, and Guam. Everything about the "Operation Z" attack was very secretive. Yes, we had a few references to "Operation Z", but were not able to figure out what that was a code for.
And once the ships left Japan, they traveled in complete radio silence. They left port, linked up at sea, then traveled to their attack point without sending any radio transmissions. That was how seriously Japan took their OPSEC. And as the war progressed, we had to get really sneaky ourselves to actually learn what most of their messages actually said. There is much more involved than just braking the code itself. There are codes within codes.
We knew the Japanese Naval Codes, and in early 1942 we started picking up chatter on an upcoming attack on "AF". The problem was, we had no idea what "AF" was. We intercepted hundreds of references to "AF", but were no closer to figuring out the destination of the attack than we were when we first heard of it. Then finally a Navy Captain got smart.
Over a timespan over a week, he ordered different Pacific outposts to send specific messages in the clear. This outpost was low on food, that outpost was low on fuel. And that is how the Navy hit paydirt. In early June Midway sent their message in the clear, their water purification system had broken down and they were low on water. And a day later, an intercept was decoded where the IJN was instructing their forces going to AF to bring additional water filtration equipment.
This was barely 2 weeks before the attack, and we now know the outcome of the Battle of Midway. Which would never have happened even with the broken code, if not for a fake US report that the island needed water.
And that is not unique. Most by now know of the Navajo "Code Talkers". However, even they used a code within a code. They Japanese were actually quickly able to secure other Navajo, and tried to order them to translate the messages. And even though they all talked "in the clear", these captured Navajo did not know the codes so were just as confused at the messages as the Japanese were. Words used such as "tree", "fish", "buzzard", "rock", "pebbles", and the like were used so even if the listener knew Navajo, the message made no sense.
And we have even seen that since then. One famous incident in the Korean War saw a Marine Mortar Platoon low on ammunition for their weapons. So they sent up a radio request that they needed a critical shipment of "Tootsie Rolls" ASAP, the code word for mortar rounds. And that message for forwarded to the Air Force, and a few hours later they were elated when an airdrop was released over their position. The men raced out to recover the shipment.
And discovered that they actually contained Tootsie Rolls. Not the mortar rounds they needed.
And it still continues to this day. As part of my duty while deployed, I had to contact an Air Force unit 4 times a day for a status update. Our only phone connection was "in the clear", so we had a sheet of code words that changed weekly. So when I called I would have to say something like "Lollypop, Grapefruit, Chevrolet, Bicycle". And over half the time they would just hang up, or it would take several minutes to get them to understand they had to get the code sheet and use it. Often times they would just translate my message, and just give me their response in the clear.
