at rough parity, Japanese naval units with superior speed and capable of hitting at ranges beyond the reach of the Americans and crewed by expertly trained personnel, would win the day. Yamamoto's revised plan The naval war that Japan fought in the Pacific during 1941-45 reflected quite a very different strategy from the one in which the Imperial Japanese Navy had been planning and training for throughout the interwar period. This was due to the views and actions of Admiral Isoroku Yamamoto who had assumed command of the Combined Fleet in August 1939. Yamamoto, virtually overnight, changed the passive wartime strategy of seizing the Philippines and waiting for an American naval advance to the western Pacific to a much more aggressive forward strategy. Yamamoto had first discussed an attack on Pearl Harbor in March or April 1940. After the completion of the Combined Fleet's annual maneuvers in the fall of 1940, Yamamoto had directed that a study of an attack on Pearl Harbor be performed under the utmost secrecy. By December of that year, Yamamoto had decided to conduct the Pearl Harbor operation. Yamamoto was convinced that war with the United States was inevitable, once the Japanese began any hostilities. He also believed that since a traditional victory against the United States was not possible, he had to shatter American morale and force a negotiated peace. For this reason he scrapped the traditional passive strategy of creating a decisive battle in the western Pacific in favor of an initial blow so crippling that it would undermine American will to fight. The operation was risky as it exposed the IJN's most powerful striking force to early destruction and consequently Yamamoto had great difficulty getting his plan to attack Pearl Harbor approved by a skeptical Naval General Staff, as the Naval General Staff was responsible for directing operations and exercised supreme command over the navy but this is not how Yamamoto viewed the situation. In a series of meetings on October 17–18, 1941, Yamamoto threatened to resign unless his plan was approved, with this threat brought the final approval of the plan as Yamamoto was viewed as too valuable to lose. What made the whole operation possible was the formidable Kido Butai with six carriers and over 400 embarked aircraft. The Japanese strategy for the coming conflict would be to fight a limited war, in which Japan would seize key objectives and