Admiral Yamamoto, commander of the Imperial Japanese Navy’s Combined Fleet, was the Harvard-educated, poker-playing mastermind of the December 7, 1941, attack.

On April 14, 1943, naval intelligence scored another code-breaking coup. The message began: “On April 18 CINC Combined Fleet will visit RXZ, R–, and RXP in accordance with the following schedule . . .” Adm. Isokoru Yamamoto was planning an inspection visit of Japanese bases in the upper Solomon Islands. The information immediately went from Commander in Chief Pacific Fleet Adm. Chester W. Nimitz

to Secretary of the Navy Frank Knox who delivered the news to President Franklin Roosevelt. Reportedly, the president’s response was, “Get Yamamoto.” Regardless of whether or not the president actually said those words, the order was given: kill the mastermind of the Pearl Harbor raid.

As Yamamoto was viewed as the architect of the attack on Pearl Harbor, President Franklin D. Roosevelt instructed Secretary of…