Japanese codes were transparent before and throughout the war. They were not Enigma codes. It was well known exactly when the Japanese planned to start the Pac

Japanese codes were transparent before and throughout the war. They were not Enigma codes. It was well known exactly when the Japanese planned to start the Pacific War, though intercepts did not say where. Many in the Navy were sure it would be at Pearl Harbor. Notably, the militarily useless battleships were there, but not the aircraft carriers.