Yamamoto was Japan’s greatest naval strategist and Commander. As Minister of Navy from 1938 and Commander in Chief of the 1st Fleet from 1939 he was responsible for the great build up and improvement of the Japanese Imperial Navy and naval air forces before the war. Although opposed to war with the United States on the grounds that Japan must inevitably lose a protracted war against such a powerful opponent, Yamamoto saw that Japan’s only chance lay in a preemptive strike to cripple the US Navy from the start. Thus he began planning the operation against Pearl Harbor in early 1940, which succeeded in crippling the US Pacific Fleet on 7 December 1941.
Despite this success the US carriers were still operational, having been sent out on maneuvers on the weekend of the Pearl Harbor attack. After the Battle of Coral Sea, in which the US lost the Lexington, and shocked by the DOOLITTLE raid on Tokyo, Yamamoto decided to try to wipe out what was left of the US Pacific Fleet in a decisive battle. The next stage of Japanese High Command strategy was to take Midway Island, which was a US base and could be used to attack Hawaii. Yamamoto devised an extremely complex plan which involved the movement of eight separate task forces, including a diversionary attack on the Aleutian Islands. However the US had the key to the Japanese Fleet code and knew of the attack on Midway on 4 June 1942. NAGUMO, the overconfident Japanese Carrier Fleet Commander, was totally out-maneuvered and lost four carriers, so the Japanese, deprived of air cover, had to withdraw.
Yamamoto never fully recovered from the shock of this defeat but continued to command fleet movements in the Solomons campaign. The Japanese Fleet suffered from huge losses of aircraft and pilots which it could never make good although several victories were scored in the waters off Guadalcanal. His last plan was for a massive naval air counterstrike, I-Go, designed to smash Allied advances, in the spring of 1943.
In April 1943 the US intercepted advance reports of Yamamoto’s tour of inspection in the Western Solomons. His aircraft and escort were shot down by aircraft from Guadalcanal on 18 April 1943 and there was a suspicion that the flight information was deliberately leaked, so that Yamamoto could die ‘in battle.’ However Yamamoto’s death was a considerable blow to Japanese morale and he received the full honor of a hero’s funeral.
Yamamoto’s great contribution to naval strategy was his early recognition of air power and the development of long- range aircraft.