I didn’t know about the direction finding method they were using to detect where the bombing runs were going until henkster’s post myself. I just always knew that the code breakers didn’t have the location for the raid nailed down.
It’s a pretty common thing really. The enemy’s code is being read so you know that they are going to hit “x”, but “x” is a new term for a location so you don’t know where. We will see this again when the upcoming attack on Midway comes and the Naval Intel boys will use a pretty slick method to find out what “x” is.
The Naval Intel boys in Hawaii were spot on figuring out what the Jap code meant for Midway. Rochefort and his crew were brilliant.