Strike force of Aichi D3A "Vals" aboard the aircraft carrier Soryu

Picture from Dull, Paul S., A Battle HIstory of the Imperial Japanese Navy(1941-1945), pg 12

    While he was Navy Vice Minister, Yamamoto made a consistent effort in keeping his country out of a war with the U.S. However, when Japan was set on an irrevocable course toward conflict he had been promoted to Commander in Chief of the Combined Fleet and as such he planned to focus all his effort on making a series of swift and decisive victories at the outset. Still, Yamamoto remained opposed to war. From his years as a student at Harvard and Naval attaché in Washington, Yamamoto understood that Japan could not fight a sustained war with America. When asked directly by the Prime Minister whether he thought Japan could achieve victory "Yamamoto replied prophetically, ‘I can raise havoc with them for one year, but after that I can give no guarantee’" (Ito 19). Yamamoto’s inspiration for the attack on Pearl Harbor had come the preceding year during spring fleet maneuvers of 1940. "It was during these maneuvers that Admiral Yamamoto, after witnessing demonstrations by carrier based planes, first conceived the idea of a surprise air attack on Hawaii. In January of 1941 Admiral Yamamoto summoned the Eleventh Air Fleet Chief of Staff, Rear Admiral Takijiro Ohnishi, and instructed him to study the feasibility of an aerial attack on the island of Oahu. Ohnishi’s report, which was completed in three months, convinced Yamamoto that it was possible to make a successful attack on the great fleet base at Pearl Harbor. Yamamoto presented the idea to his staff in May as a subject for further study. They voiced much skepticism, and Ohnishi himself cautioned that there was only a fifty-fifty chance for success. Yamamoto had become obdurate, however, and in July he ordered special training procedures for all the air fleets of his command" (Ito 33-34). Yamamoto became further convinced of the probable success of a surprise air attack by the British victory at Italian port of Taranto. "Yamamoto called for urgent reports from the Japanese naval attaches in Rome and London. He closely studied the details of the successful attack on the Italian battleships in the enclosed harbour of Taranto" (Potter 53). To better understand what such an attack would entail at Pearl Harbor, Yamamoto had his fleet train accordingly. "It was customary for the Naval General Staff to set up a war game objective each year and for Combined Fleet to develop plans to achieve that objective. For more than twenty years the objective had been ‘the annihilation of the United States Fleet.’ The only difference in the summer of 1941 was that the means and area for achieving this goal had been changed from surface battle in the Marshalls to air attack on Hawaii" (Ito 34). By this point Yamamoto was convinced that if hostilities broke out, an attack on Pearl Harbor with a simultaneous offensive into the South Pacific was Japan’s only course of action, but he was strenuously resisted by other senior naval officers. "Vice admiral Kondo Nobutake, for example, maintained that Japan should attack Malaya and the Dutch East Indies only, and numerous high-ranking officers opposed the Pearl Harbor plan. The traditional navy strategy had been defensive: forcing the American fleet to cross the Pacific; attriting the fleet through submarine attacks during its voyages, and attempting to win what was expected to be the decisive battle near Japan (Sagan 913). By the time negotiations with the U.S. had all but failed and war was imminent, Yamamoto was only able to gain the support of the Navy by threatening to resign if the attack was not approved. On November 3^rd, 1941 Yamamoto received the permission of Admiral Nagano, the Chief of Staff to proceed with the operation. "When Yamamoto set December 7, 1941 as X-Day he formally appointed Vice-Admiral Chuichi Nagumo as commander of the Pearl Harbor striking force. He had a task force of twenty-three warships including six aircraft carriers, Akagi, Kaga, Soryu, Hiryu, Zuikaku, and Shokaku" (Potter 71). Distributed among each carrier’s complement of aircraft was an ordinance load of specially modified wooden-finned torpedoes designed to run in the shallow waters of Pearl Harbor. Since war had not been declared Yamamoto order the strike force to approach the Hawaiian Islands from the north where they would hopefully avoid the shipping lanes and remain undetected until it was too late. Initially, the fleet had been staged in Tankan Bay among the Kurile Islands. From there Yamamoto ordered that they proceed on the 26^th of November through the Northern Pacific to arrive in Hawaiian waters on the morning of the 7^th of December and deal the U.S. fleet "a mortal blow" (Potter 79). As is now a well-known fact of history, Yamamoto’s plan was an overwhelming success. Four U.S. battleships were sunk and four more were heavily damaged. However, much to the disappointment of the Japanese, no U.S. carriers were present at Pearl Harbor and Admiral Nagumo did not seek them out. Additionally, the oil tank farms and dockyards at Pearl Harbor were left intact as Nagumo rapidly withdrew after launching a single two-wave strike. Though Japan "went wild" over her early victories, Yamamoto, true to his nature remained "sober and reflexive" (Ito 55).

Map of Pearl Harbor