In April 1940, obsolescent British Swordfish biplanes, nicknamed "stringbags" for their flimsy construction, struck the Italian fleet at Taranto. Within minutes significant damage was done to Italy’s Mediterranean Fleet. To get around the inability to operate torpedoes in the shallow waters of the harbor, the British attached fins to the tail.
Admiral Isoroku Yamamoto and his staff studied the attack on Taranto, even constructing models of the harbor to study it. Yamamoto was in need of a way to radically change the predominant doctrine that was the hallmark of both the Japanese and Allied Navies — a mainforce engagement somewhere near the Philippines. Under various war plans, both sides sought a major engagement where the guns of the battleships would be bought to bear on the enemy fleet in a decisive engagement. Togo had done this at Tsushima, and his junior officers, now running the Imperial Japanese Navy, wanted to do the same thing to the United States Fleet.
But two new weapons were available in 1941 that Togo did not have in 1905. The aircraft and the submarine changed everything, and only a few officers in both navies knew it. Yamamoto recognized the importance of the aircraft, but not the submarine. His navy possessed more carriers than any other, and his aircraft were the finest shipboard military planes anywhere. The man who led this First Air Fleet, as it was designated, was not equal to the task, but Chuichi Nagumo would carry out his orders and reap the short glory. Yamamoto himself had served as captain of some of the larger ships, and he held those men close to his heart.