During World War II, Isoroku Yamamoto was the Japanese Marshal Admiral and commander-in-chief of the Combined Fleet.  He served in the Imperial Japanese Navy from 1901 until his death in 1943.


Yamamoto graduated from the Imperial Japanese Naval Academy and throughout his service held a number of significant posts.  He was also involved in a number of the changes and reorganizations that occurred during his service and was instrumental in the development of the Japanese Naval aviation.


Early Naval Career

Yamamoto graduated from the Japanese Naval Academy in 1904.  He was first assigned to the armored cruiser – the Nisshin – during the Russo-Japanese War.  During the Battle of Tsushima, when the cruiser was repeatedly struck by the Russian battleline, Yamamoto was wounded and received injuries causing him to lose an index and middle finger.  In 1914, he entered the Naval Staff College where he graduated in 1916 as a Lieutenant Commander.


Yamamoto 1During the next two decades, Yamamoto would be involved in a number of areas.  He began plans for the Naval fleet to become more effectively used as gunboats as opposed to simply transportation for the land invasion forces.  Along with his opposition to invade China, Yamamoto was also against waging war with the United States.  His hesitance was due in part to his being educated at Harvard University from 1919-21.  He held two posts in Washington DC as an attaché, a position which provided him the opportunity to learn fluent English.


Below are some highlights from his early career:

  • 1923 – Promoted to Captain
  • 1924 – Visited the US Naval War College as part of a Japanese delegation
  • 1928 – Commander of the cruise – Isuzu (this was his first command)
  • 1930 – Attended the London Naval Conference – at which time he was a Rear Admiral
  • 1934 – Attended the London Naval Conference as a Vice Admiral


Yamamoto personally opposed the following:

  • 1931 – The invasion of Manchuria
  • 1937 – Land war with China
  • 1940 – Tripartite Pact with Germany and Fascist Italy


In 1938, a number of younger army and naval officers began to speak disapprovingly of Yamamoto and a number of other Japanese admirals for their strong stance against the Tripartite.  They felt they were going against ‘Japan’s natural interests’.  This created a lot of conflict and concern for Yamamoto’s safety.


1940 – 1941

On November 15, 1940, Isoroku Yamamoto was promoted to Navy General.  This came as a surprise due to the many military decisions he openly opposed.  However, he was well-liked and respected by the men and officers within the fleet he commanded and he had a close relationship with the imperial family.  Yamamoto was also accepted by Japan’s naval hierarchy.


Soon, Yamamoto realized involvement in the war was immanent and began planning for what he hoped to be a quick victory by destroying the U.S. fleet at Pearl Harbor.  In conjunction with this strike, he planned to thrust into Southeast Asia – focusing on the Dutch East Indies, Borneo and Malaya – as these areas were rich with both oil and rubber resources.


pearl harbor 1On December 7, 1941, Yamamoto’s plan was put into action.  Six carriers of the First Air Fleet launched 353 aircraft on Pearl Harbor.  The mission was considered a success based on its intent to sink a minimum of four American battleships and to prevent interference from the US Fleet for at least six months to allow Japan time to advance southward.  Their intention to also take out American aircraft carriers was thwarted as these were out to sea when Pearl Harbor was attacked.


The Pearl Harbor attack was initially devastating for the United States.  Five of their battleships had been sunk and another three were damaged.  An additional 11 cruisers, destroyers and ancillaries were either sunk or extensively damaged.  The Japanese, however, had only lost 29 aircraft with an additional 74 receiving damage as a result of anti-aircraft fire.  However, those damaged were predominantly dive and torpedo bombers which had a serious impact on the available firepower after the first two rounds of attacks.  This reflected in Japan’s decision to not seek and destroy the American carriers and is at the center of a number of controversies.  Auxiliary


The attack on Pearl Harbor for all practical purposes was a success.  However, strategically, it roused the passion of the American people who sought revenge for this ‘sneak attack’ which came prior to war even being declared.  The Japanese were able to move forward successfully for the next six months capturing a number of territories and islands.  However, the pendulum began swinging in a new direction when they were defeated at the Battle of Midway (June 4 – 7, 1942).

Pearl Harbor TN

The Armed Forces History Museum in Largo, FL has the scale models of the ships which were used in the filming of Tora! Tora! Tora!


December 1941 Up To the Battle of Midway (June, 1942)

Once the American Fleet was devastated and considered neutralized at Pearl Harbor, Yamamoto began to implement the larger war plan of Japan.  They began striking installations throughout the Pacific belonging, not only to the Americans, but also the British, Dutch and Australians.  Just hours after the bombing of Pearl Harbor, Japan’s 11th Air Fleet took the Americans of the 5th Air Force by surprise with a ground assault in the Phillippines.  Japan went on to sink the British battleship HMS Prince of Wales and the HMS Repulse a British battle cruiser.  They continued sweeping the Pacific and by March of 1942, they had been managed to achieve their initial objectives with considerable speed and minor loss.

Yamamoto and some of the other Japanese military leaders waited in hopes the United States and/or Great Britain would request negotiations for a cease-fire or even better - a peace treaty.  Once they realized neither country was interested in any negotiations, the Japanese began to take measures to secure their newly acquired territory and plans to acquire additional ones in an attempt to force at least one – if not more – of the Allies out of the war.


New GuineaTheir initial plans to invade India or Australia and to seize Hawaii had to be set aside.  Instead support was given for the army to thrust into Burma and to attack both New Guinea and the Solomon Islands.  In Burma, the Japanese were hoping to link up with Indian Nationalists in Burma who were currently involved in revolting the British rule.  The strikes in New Guinea and the Solomon Islands were planned in hopes of disrupting the Australian’s sea line of communication with the U.S.  Yamamoto was agitated as he was hoping for an offensive battle in the east, which he felt would finish the American fleet.  However, Naval General Staff officers were not willing to take that risk.


On April 18, 1942, Tokyo and the area around it were attacked by the “Doolittle Raid”.  As a result, the Naval General Staff gave Yamamoto permission to implement his Midway Operation.  He began to plan a rush for both Midway and the Aleutians.  He also planned to take the islands of Tulagi and Guadalcanal so the Japanese could benefit from their seaplane and airplane bases.


Over the next few weeks, the Japanese would suffer a number of setbacks including the sidelining of two of their ships – Shokaku and Zuikaku.


Battle of Midway

For Yamamoto, Midway Island was to enhance his plans to disable the US pacific Fleet long enough for the Japanese to fortify their defensive perimeter in the Pacific island chains.  He believed it was crucial for Japan to initially implement an offensive decisive battle.


Aleutian IslandsThe plan was for the Fifth Fleet to attack the Aleutian Islands while the First Mobile Force (which consisted of four carriers, two battleships, ten cruisers, 21 destroyers and 11 transports) would land an estimated 5,000 troops whose goal was to seize the island from the US Marines.


It was anticipated that seizing Midway would draw the US carriers west and right into a trap which where they would be engaged and destroyed by the First Mobile Force.  Afterwards, the First Fleet would be joined by the Second Fleet to take care of any remaining US surface forces by destroying any remaining ships in their Pacific Fleet.


Included in Yamamoto’s plans were two security measures.

1)      An aerial recon mission above Pearl Harbor (Operation K) to determine whether there were any American carriers there.

2)      Have a line of subs set so any movement by the American carriers towards Midway could be detected, giving the Japanese time to prepare to confront them.


Admiral Nimitz

Admiral Nimitz

The plan appeared to be well thought out, organized and well-timed from the Japanese standpoint.  Yamamoto appeared to have the upper hand and a crushing defeat seemed inevitable.  However, American cryptographers managed to decipher the Japanese code giving them insight on Yamamoto’s battle plans and making it possible for Admiral Nimitz, the Pacific Fleet Commander, to evade not only the security measures Yamamoto had put into place, but also position his forces (though outnumbered) in a way that would result in a devastating ambush.


In May, after an initial raid by Japanese flying boats, Admiral Nimitz sent a minesweeper to safeguard the refueling point that was assigned for Operation K.  This caused Yamamoto’s Recon plan to be aborted and left him unaware as to what – if any – Pacific Fleet carriers remained in Pearl Harbor.  His tactics were questioned as the recon was pertinent to the mission.   Also questioned was why Yamamoto’s subs did not maneuver sooner.


Yamamoto also dispatched his carriers earlier than anticipated.  On their way to Midway, they passed by the submarines that were an intended picket line force.  This also negated his back-up security.   Admiral Nimitz set a strike in motion on June 4, 1942.  The American carrier-based aircraft were able to catch the Japanese carriers at a particularly vulnerable time and managed to destroy four carriers of the Kido Butai.


Despite the destruction of his air power and the fact his forces were not in position for fleet battle, Yamamoto tried to use the remaining forces to trap the American forces.  The plan looked good on paper, but with his combatants too far from Midway, in addition to a number of other factors which would weigh against him, Yamamoto eventually withdrew his plans to invade Midway.


Imperial Japanese Navy After Midway

Despite the Japanese losing some of their momentum after Midway, they were still considered a very powerful force that was more than capable of regaining their advantage.   Operation FS was a plan implemented to gain control of Samoa and Fiji, which would cut the Americans off from Australia.  The Japanese felt this would diminish the threat of General MacArthur and the American and Australian forces which were in New Guinea.


Fleet Admiral Ernest King

Fleet Admiral Ernest King

Progress continued on the battlefield being developed on Guadalcanal, which did not go unnoticed.  Admiral Ernest King took note and recommended – via the Joint Chiefs of Staff - an immediate counterattack by the Americans.   This hastened the American’s invasion of Guadalcanal and Marines landed on the island in August of 1942.  Though they beat the Japanese to the punch, a bitter battle still ensued, lasting until February of 1943.


Yamamoto still continued as Commander-in-Chief so as not to diminish the morale of the Combined Fleet.  The Naval General Staff, however, had lost confidence in Yamamoto after the defeat at Midway.  They were no longer willing to further engage in any of his risky tactics.


Problems continued for the Japanese.  Due to their involvement in New Guinea and Central pacific, their troops were spread thin.  This caused a number of setbacks.  Yamamoto began a small series of attacks throughout the south and central Pacific, but it did nothing more than serve as a slight sting to the Americans and created losses he could not afford.   In September and October, three major carrier battles were planned which Yamamoto personally commanded.  He added two surface battles in November, which were set up to coincide with pushes by the Japanese army.  The army, however, was unable to hold up its portion of the operation on both and thus, the battles were derailed.


In several naval battles around Guadalcanal, the Japanese naval forces managed to inflict significant losses and damage to the US Fleets, but was unable to lure them into any decisive action.  What resulted was the waning of Japan’s Naval strength.  Their air groups continued to experience severe losses of both their dive-bomber and torpedo-bomber crews.   Japan had no hopes of matching the US in the large number of well-trained pilots to , thus their land-based and naval aviation started to decline.

Japan continued to suffer the loss of a number of destroyers, which were already in short supply.  In February of 1943, Japan lost Guadalcanal and made no additional attempt to seek any major battle in the Solomon Islands, though smaller battles continued for a while.  At this point, Yamamoto reduced the load from air battle (as a result of the depleted carriers) and began focusing on land-based naval air forces.


After Guadalcanal

Following his defeat at Guadalcanal, Yamamoto went on an inspection tour of the South Pacific.  U.S. Naval intelligence intercepted and decrypted messages regarding his tour which gave them very specific details such as location, arrival and departure times and the number of plans involved in transporting and accompanying Yamamoto.


President Roosevelt ordered Frank Knox - the Secretary of the Navy - to ‘Get Yamamoto’, who would be flying from Rabaul to Balalae Airfield on the morning of April 18, 1943.  In turn, Knox relayed President Roosevelt’s wishes to Admiral Nimitz who spoke with Admiral Halsey, Jr. – the commander of the South Pacific.  Following their discussion, authorization was issued for a mission to intercept Yamamoto’s flight on April 17th.  The orders were to intercept the flight en route and ‘shoot it down’.  Pilots were selected from three different units for the mission, but were only told they’d be intercepting an ‘important high officer’.  They were not provided with a specific name.  They would be flying the Lockheed P-38 Lightning as this was the only aircraft which had the range necessary to intercept and engage.


Photo of crash site

Photo of crash site

The morning of the trip, Yamamoto was being urged by the local commanders to cancel his plans as they feared he would be ambushed.  He did not heed their warnings and continued as originally scheduled.  They were intercepted by 16 P38’s which engaged in dog fights with the six A6M Zeroes which were escorting Yamamoto.  One of the first two Japanese planes engaged by 1st Lt Rex Barber turned out to be Yamamoto’s.  Barber riddled the first plane with gunfire until its engine began to spew smoke and then began to attack the second transporter.  The first aircraft, Yamamoto’s plane, lost control and crashed in the jungle.


The next day, a search Japanese search party located the crash site and Yamamoto’s body.  It was later determined that a head wound as a result of gunshot was the actual cause of death.  Yamamoto’s remains were cremated.  Some of the ashes were interned in Tama Cemetery, a public burial ground in Tokyo.  The rest of the ashes were interned at the temple of Chuko-ji, his ancestral burial grounds in Nagaoka City.


World War II Japanese Admiral Isoroku Yamamoto would posthumously receive the title “Marshal”, be awarded the ‘Order of the Chrysanthemums (1st Class) and eventually the Nazi Germany’s Knight’s Cross of the Iron Cross with Oak Leaves and Swords.