What was the codename for Japan’s Pearl Harbor attack plan?

Operation Z was the codename for Japan’s Pearl Harbor attack plan.

Japanese naval planners used “Operation Z” for the carrier strike against the U.S. Pacific Fleet. The plan developed from Admiral Isoroku Yamamoto’s belief that Japan needed to cripple American naval power in the Pacific before pursuing its wider wartime objectives.

Minoru Genda helped refine the operational details, including the use of torpedo aircraft in the shallow waters of Pearl Harbor. The plan required a long, secret voyage across the North Pacific and depended on surprise.

Operation Z is not the same as the broader Japanese strategy for the opening of the Pacific War. It specifically referred to the Pearl Harbor strike plan. The name is also distinct from Operation K, a later Japanese mission involving long-range flying boats that attacked Oahu in March 1942.