TheCodeBreakers
Nimitz
had sent a North Pacific Force of cruisers and destroyers to protect his
flank. Like some other officers, its commander, Rear Admiral Robert A.
Theobald, suspected that the Japanese had "planted" the information on
which U.S. intelligence estimates were based. They were probably
thinking of dummy radio activity to fool the traffic analysts, for Nimitz
never mentioned the supersecret cryptanalytic successes to his force
commanders—not even in the briefings just before the battle. The
suspicions of the doubters may have been reinforced by an intercepted
plaintext request of a Japanese Army officer that all mail for his unit be
addressed to Midway after June 5; as General Marshall later said, "that
seemed a little bit too thick." Furthermore, Nimitz himself warned of
Japanese trickery when arranging for identification by radio in his
Operation Plan 29-42: "The Japanese are adept at the practice of
deception
annaabi.ee 
