The U.S. Navy understood how carriers could surprise Oahu because it had demonstrated the method itself. Its exercises, however, placed the attack within an amphibious operation or an ongoing conflict supported by a larger campaign. American planners therefore expected an attacker to bring a safety net and judged Japan's lightly escorted six-carrier opening move as excessively exposed. That assumption projected American risk standards onto an opponent following a different strategic logic. The mismatch helped a familiar tactical possibility look implausible in the actual circumstances of December 1941.
Chapter · 54:15-56:13
Why American planners discounted the Japanese strike
American exercises assumed an ongoing campaign or amphibious assault, making Japan's exposed opening strike seem too risky for the first move of a war.