Fleet Admiral Isoroku Yamamoto, 4 April 1884 – 18 April 1943, was the planner behind the attack on Pearl Harbor. He knew Japan could not beat the US in an all out war, but he figured his plan could hurt us enough to allow Japan time to cement its hold in key areas that the US could not do enough to weaken Japan and would eventually work out a peace treaty.

Yamamoto was born Isoroku Takano. Isoroku is a reference to his father’s age when he was born, 56. Takano is taken from his father’s name, Sadayoshi Takano. His father was an intermediate samurai of the Nagaoka Domain. In 1916 he was adopted by the Yamamoto family and he took their name. It is said he was adopted by the family in order to carry on the Yamamoto name. The Yamamoto family was descendents from Yamamoto Tatewaki a samurai of the late Edo Period in Japan.

Yamamoto joined the Navy in 1904. He severed on the cruiser Nisshin during the Russo-Japanese War. During the war he was wounded at the Battle of Tsushima, losing his index and middle fingers on his left hand. He returned to the Naval Staff College in 1914, emerging as a lieutenant commander in 1916.

During the 1920’s and 30’s he was opposed to war with the US. He served as naval attaché twice, spent time studying at Harvard and was an Admirals aide. He knew the US had the industry to out produce Japan and the natural resources to support it as well. He had various commands when he returned to Japan including the famous IJN Akagi.

He was at the forefront of Japan’s
Naval air arm during the 1930’s. He served as head of the Aeronautics Department before accepting a post as commander of the First Carrier Division. His importance to Japan’s Navy was such that Japan included him on the negation team to both of the London Naval Conference of 1930 and 1934.
He continued to lead Japan’s navy and shape its future right up until the beginning of the war. Although Hideki Tojo became prime minister and shifted resources toward the Army Yamamoto was able to arm the Navy and make it one of the most formidable in the world.

Planning for the attack on Pearl Harbor was only meant to delay any US response to Japan’s expanding their sphere into the Dutch East Indies. Yamamoto knew it was only a matter of time after the US was provoked before it was able to rebuild its power. He never envisioned Japan being able to defeat the US. The attack on Pearl Harbor was planned to inflict the most damage possible to the US. Given a total success of the attack Yamamoto knew he had limited time to make his defensive perimeter as strong as possible.

After the attack was over Yamamoto set into motion his Naval strategy to strengthen Japan’s position in the Pacific. Repeated success after success made it appear Japan would be able to hold onto its newly captured territory. Japan’s Navy was finally put into check after the battle of Coral Sea and Midway.

Yamamoto continued to oversee Japan’s Navy right up until he was targeted by US warplanes out of Guadalcanal. His plane was intercepted and shot down on April 18, 1943. In a single stroke, Japan lost one its greatest military minds.

One of the wars most famous quotes has been attributed to Yamamoto, "I fear all we have done is to awaken a sleeping giant and fill him with a terrible resolve." Although portrayed in film it is debated if he actually said it. This will be covered later.