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A biography of isoroku yamamoto the japanese man who planned pearl harbor

Thus, increasingly, war became the only remaining option. An Imperial Conference on July 2, 1941, confirmed the decision to attack the Western powers. In early September, the Emperor declined to overrule the decision to go to war and the final authorization for war was given a biography of isoroku yamamoto the japanese man who planned pearl harbor December 1.

Yamamoto on his flagship Nagato before the war. Naval History and Heritage Command. It says much for his influence and powers of persuasion that the event even occurred. Yamamoto was not the first person to think of attacking the American naval base at Pearl Harbor. As early as 1927, war games at the Japanese Navy War College included an examination of a carrier raid against Pearl Harbor. The following year, a certain Captain Yamamoto lectured on the same topic. This clearly indicates that Yamamoto did not copy the idea of attacking a fleet in its base after observing the British carrier raid on the Italian base at Taranto in November 1940.

After the Taranto attack, Yamamoto wrote to a fellow admiral and friend stating that he had decided to launch the Pearl Harbor attack in December 1940. If it is to be believed that Yamamoto decided on his daring attack as early as December 1940, several issues are brought into focus. First and foremost, it can be established that Yamamoto had decided on this risky course of action even before the advantages and disadvantages of such an action could be fully weighed.

Also, in late 1940, Yamamoto did not even possess the technical means to mount such an operation. Another question that needs to be asked is why Yamamoto thought it was his job to formulate grand naval strategy, which was the responsibility of the Naval General Staff. The planning for the attack was a confused and often haphazard process. Gradually, and against almost universal opposition, Yamamoto made his vision become reality.

In a letter dated January 7, 1941, Yamamoto ordered Onishi to study his proposal. This was followed by a meeting between Yamamoto and Onishi on January 26 or 27 during which Yamamoto explained his ideas. Onishi was selected by Yamamoto to develop the idea since he was the chief of staff of the land-based 11th Air Fleet and was a fellow air advocate and a noted tactical expert and planner.

Onishi pulled Commander Genda Minoru into the planning in February. With Yamamoto providing the driving vision and political top-cover, Genda became the driving force in actually turning the vision into a viable plan. Genda was charged with completing a study of the proposed operation in seven to ten days. The subsequent report was a landmark event in the planning process since most of his ideas were reflected in the final plan.

On November 15, 1940, Yamamoto had been promoted to full admiral and, as the planning for war increased in intensity, he began to wonder about his future.

It was customary for the Commander-in-Chief of the Combined Fleet to serve for two years. In early 1941, Yamamoto was thinking of his impending change of duty and was pondering retirement. During this time, he told one of his friends: In spite of his desires, Yamamoto did not leave his post in mid-1941 after his two years were up.

Since the Naval General Staff had responsibility for the overall formulation of naval strategy, any questions about whether, and how, to attack the United States in the initial phase of the war clearly fell under its jurisdiction.

However, in another indication of the muddled Japanese planning process, Yamamoto wanted to seize this prerogative for himself.

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In late April, Yamamoto entrusted one of his principal Combined Fleet staff officers to begin the process of convincing the skeptical Naval General Staff. The initial meeting did not go well for Yamamoto since the Naval General Staff did not believe his contention that the attack would be so devastating that it would undermine American morale. Their biggest concern was that the Pearl Harbor attack was simply too risky.

Though the Naval General Staff remained opposed to the idea, it did agree that the annual war games would include an examination of the Pearl Harbor plan. These began on September 11 with the first phase focusing on the conduct of the southern operation. On September 16, a group of officers selected by Yamamoto, including representatives of the Naval General Staff, began a review of the Hawaii operation. The results of this controlled tabletop maneuver seemed to confirm that the operation was feasible, but also served to confirm that it was risky and that success depended heavily on surprise.

At the end of the two-day exercise, the Naval General Staff remained unconvinced. Basic concerns, such as whether refueling was possible to get the entire force to Hawaii and how many carriers were to be allocated to the operation, also remained unresolved. Yamamoto became enraged when he learned that once again the Naval General Staff had rejected his plan.

The Legacy Of The Man Who Planned The Pearl Harbor Attack

For the first time, fleet and midget submarines were included in the planning for the Pearl Harbor attack. The next day, there was a conference to review the plan, and where all admirals present were invited to speak. All but one was opposed to the Pearl Harbor attack. When they were done, Yamamoto addressed the assembled group and stated that as long as he was in charge, Pearl Harbor would be attacked.

With the support of his own commanders assured, Yamamoto was determined to bring the issue to a head with the still skeptical Naval General Staff. In a series of meetings on October 17—18, Yamamoto played his ace card. His staff representatives revealed that unless the plan was approved in its entirety Yamamoto and the entire staff of the Combined Fleet would resign. Since to Nagano the notion of going to war without Yamamoto at the helm of the Combined Fleet was simply unthinkable, this threat served to bring the Pearl Harbor debate to a close.

In the end, it was not logic that carried the day for Yamamoto, but the threat of resignation and it was not to be the last time that he would use this tactic.

Yamamoto and the Planning for Pearl Harbor

The staff of the First Air Fleet conducted the actual planning for the operation. On April 10, 1941, Yamamoto had given the go-ahead to form the First Air Fleet by combining Divisions 1 and 2 into a single formation.

This was a revolutionary step which had been considered for some time, and in April Yamamoto judged that the time was right to take that step.

As an air power advocate, he felt it was necessary to maximize the striking power of the carrier force. By concentrating the carriers into a single force, Yamamoto had created the most powerful naval force in the Pacific and gained the means by which to conduct his Pearl Harbor operation.

By late April, the staff of the new First Air Fleet, led by Genda, who had been assigned as staff air officer, was engaged in fleshing out the details of the operation.

Gradually, the problems associated with refueling, executing torpedo attacks in the shallow waters of Pearl Harbor, and making level bombing against heavily armored battleships a viable tactic, were solved. Battleships were so deeply entrenched in the minds of the American public as a symbol of naval power that by shattering their battle fleet Yamamoto believed American morale would be crushed.

He even considered giving up the entire operation when it appeared that the problem of using torpedoes in the shallow harbor could not be solved — torpedoes were required to sink the heavily armored battleships, whereas dive-bombing would have sufficed to sink the lightly armored carriers. The final plan was completed by Genda and reflected the difference in opinion between Genda and Yamamoto.

Genda, the air power zealot, devoted more weight to sinking carriers, and less to sinking battleships. The first wave of the attack included 40 torpedo planes which were broken down into 16 against the two carriers that might be present, and the other 24 against as many as six battleships, which were vulnerable to torpedo attack. Level attack was the only way to strike inboard areas of the battleships when two ships were moored together.

Fifty-four dive-bombers and the escorting fighters were ordered to attack the many airfields on Oahu. In all, the six carriers in the attack force planned to use 189 aircraft in the first wave. The second wave was planned to comprise 171 aircraft.

Isoroku Yamamoto

The relatively small bombs carried by the dive-bombers were insufficient to penetrate battleship armor, so the first wave had the job of inflicting maximum damage on the heavy ships. The remainder of the second wave aircraft, which included 54 level bombers, was to complete the destruction of American air power on Oahu in order to prevent any return strikes on the Japanese carriers.

Despite the fact that the strikeforce the Kido Butai embarked at least 411 aircraft for the operation, making it the most powerful naval force in the Pacific, the attack remained a risky undertaking.

If the Americans detected the raiders in time to prepare their air defenses, the attack could be catastrophic for the Japanese, a fact they had ascertained in their pre-attack gaming.

If exposed to counterattack, the Japanese carriers were vulnerable. The transit was undetected and by the morning of December 7, from a position some 200 miles north of Oahu, six Japanese carriers had begun to launch the first attack wave.