MLU FORUM - Ultra Japanese messages

I've seen various security classifications and handling instructions, and like the plain speaking warning on these ones.

The style of the translation and how it is formatted are equally interesting. Whoever handled the original and then the translation was doing their best to extract as much information as possible.

For example the roundabout reaction to a US civilian radio broadcast announcing a Japanese ship's loss, says there were Japanese intercept stations doing lots of long range signals intelligence. Where the text notes the Japanese navy asked all of its ships to check in, tells me that they didn't have an especially routinized daily (or more) situation report program. One way ULTRA apparently cracked the German navy cyphers was to overlay intercepted standardized message formats to pick out common words, letters and numbers based on whatever scraps of code breaking grids at hand.