Isoruku Yamamoto - Planning Pearl Harbor

In November 1941, nothing appeared amiss at the major Japanese seaports. Hundreds of Japanese sailors could be seen frequenting the usual bars and hangouts. At least they looked like sailors; actually, they were soldiers wearing naval uni-forms. It was essential for foreign observers to see sailors walking around. Otherwise, they might wonder where all the sailors were, where their ships were,and what they were doing. In reality, Japan was getting ready to launch massive strikes by land, sea, and air throughout the Pacific.

Many of the sailors were already on ships in a task force in the Kurile Islands, north of Japan. That fleet was under the command of Vice Admiral Chuichi Nagumo, who waited anxiously for the signal to sail. His force consisted of two battleships, two cruisers, several destroyers and tankers, and, most importantly, six of Japan’s largest aircraft carriers.

On November 26, 1941, the word came from Admiral Isoruku Yamamoto to proceed. Under strict radio silence, the task force sailed eastward. Its destination was Pearl Harbor.

Isoruku Yamamoto, the man who planned Pearl Harbor, had many misgivings about warring on the United States. But once assigned the task, he carefully mapped every detail of the daring and dangerous mission.

Yamamoto’s Rise in the Japanese Navy

Yamamoto was born in Nagaoka, Japan, in 1884. Seeking a naval career, he attended the Naval Academy, graduating in 1904. He was commissioned an ensign and saw action in the Russo-Japanese War.

By the time World War I began, Yamamoto was a commander on duty at the Japanese Imperial Naval Headquarters in Tokyo. His superiors had high expectations for him, and he was sent to the United States to study at Harvard University. In his two years there, he acquired tastes for many American pastimes, from baseball to poker. He also became intrigued by the potential of aviation. After a stint back in Japan, he became naval attaché in Washington, D.C., a post he held from 1925 to 1927. During his tour of duty in America, Yamamoto became deeply impressed with America’s industrial potential. It was, he believed, a vital element in any future war.

By the early 1930s, he was a rear admiral and a firm advocate for strengthening Japan’s naval aviation. He had become a naval pilot. In the mid-1930s, the major powers, including Great Britain, France, Germany, Japan, and the United States, were attempting to set limits on armaments. Yamamoto, as head of the Japanese delegation attending these international meetings, announced that Japan could not accept unfair limitations on its military strength.

As Yamamoto rose through the ranks in the navy, he fought for more planes and carriers. In August 1939, he became commander of the entire Japanese fleet.

Planning the Attack on Pearl Harbor

When the Japanese government decided to conduct offensive operations through-out the Pacific, Yamamoto was assigned the task of taking on the American Pacific fleet. Although he personally felt that Japan would eventually be beaten in any war with the United States, Yamamoto dutifully prepared for the attack on Pearl Harbor.

Without any formal declaration of war, more than 350 Japanese planes would take off from carriers and attack specific ships at anchor in the naval base. Hickam Air Force Base and the Pearl Harbor Naval Air Station would also be bombed. In addition, a fleet of submarines would lie in wait off Oahu in case some ships tried to escape the trap.

The sneak attack on Pearl Harbor was successful beyond the dreams of the Japanese militarists: 19 American warships were sunk or damaged, and many American planes destroyed on the ground; 150 of the 200 naval aircraft were damaged. More than 2,500 men were killed. The Japanese losses totaled just 29 planes and l00 men.

After Pearl Harbor, Yamamoto would experience both successes and failures. He paved the way for Japan to overwhelm Malaysia and the Dutch East Indies. His troops would be turned back, however, at the Battle of the Coral Sea and decisively beaten at Midway. 

Nevertheless, the United States was well aware of his skill and his potential for inflicting damage on Allied forces. The decision was made to assassinate him. Through official messages intercepted by American monitors, it was learned when and where Yamamoto would be inspecting Japanese installations in the South Pacific. On April 18, 1943, American planes shot down the Japanese bomber carrying Yamamoto. It was not until late May that Japan announced that he had been killed in action against the enemy.

The Legacy of Pearl Harbor

The Japanese attack on Pearl Harbor was crucial for three reasons:

1. It was one of the greatest victories (from the Japanese perspective) and one of the most humiliating defeats (from the American point of view) in the history of naval warfare.
2. It forced the United States into World War II, uniting people throughout the country behind the war effort.
3. It forced Adolf Hitler’s (Number l) hand. Under his pact with Japan, he was obligated to declare war on the United States, and he did so. The isolationists who had opposed getting into war with Hitler now had no other option. The declaration of war against Germany simply recognized the fait accompli. After President Roosevelt (Number 2) had signed off on it, he told the American people, “Now we are all in it, all the way.”