Admiral Isoroku Yamamoto: His Life, the Attack on Pearl Harbor, and the U.S. Operation to Assassinate Him

Image: Admiral Yamamoto circa 1940.

Admiral Isoroku Yamamoto (1884-1943) was the Marshal Admiral of the Imperial Japanese Navy (IJN) leading up to World War II until his death in 1943 as the result of an operation by the United States to assassinate him. However, it was less-so his position as the leader of the IJN that put him in the U.S.'s crosshairs. Rather, he was the mastermind of the surprise attack on Pearl Harbor on December 7th, 1941 that resulted in 2,403 American deaths, the crippling of the U.S. Navy's Pacific Fleet, and forcing the United States to enter World War II.

This post follows roughly three separate parts which I think are important to understand the full context here, they are as follows:
1. Who was Admiral Yamamoto? (Begins here)
2. The Attack on Pearl Harbor and Guadalcanal Campaign (Begins at #6)
3. Operation Vengeance and Yamamoto's Death (Begins at #11)

Image: Yamamoto (left) circa 1916

First, some background on who Yamamoto was to give context. Yamamoto's career in the IJN began in 1904 began when he graduated from the Imperial Japanese Naval Academy and he was quickly given his first command, the cruiser Nisshin, which he lead through the Russo-Japanese War of 1904-1905. He choose to continue his education following this, attending Japan's Naval Staff College and reaching the rank of commander by 1919.

Image: (from left to right) Yamamoto, U.S. Secretary of the Navy Curtis Wilbur, Japanese Captain Kiyoshi Hasegawa, U.S. Admiral Edward Eberle in 1926.

Here's where things start to get interesting. Yamamoto would attend Harvard University from 1919-1921 (yes, that Harvard), serve as a naval attaché in Washington, D.C., and travel all across the U.S. during his time there committing himself to learning all about American culture. He was also part of a delegation that visited the U.S. Naval War College. Here, Yamamoto discovered the potential of naval aviation, which was largely looked down upon by others until WWII.

Image: Yamamoto (second from left) circa 1924.

It's important to note that Yamamoto's time in the U.S. was spent because he genuinely felt like he had a lot to learn from the them, not because he wanted to "study up on future opponents." He adamantly opposed any suggestions of war between the U.S. and Japan and supported expanding relations with them. He had a large role in both of the London Naval Conferences, advocating for limitations on the size and number of ships for all major naval powers. Yamamoto opposed the invasion of China in 1931, opposed the alliance between Japan, Nazi Germany, and Italy, and even apologized to the U.S. Ambassador for the 1937 bombing of the USS Panay in China.

Image: Admiral Yamamoto in 1939.

His unwavering opposition the above lead to him being targeted by pro-war militarists that filled the Japanese government/military (there was no separating the two by the 1930s). The Imperial Japanese Army even went as far as to spy on him by sending him "guards". A friend, Admiral Mitsumasa Yonai, ended up as the acting Navy Minister and assigned Yamamoto as the commander of the Combined Fleet. Yonai saw Yamamoto as the most fit for the role, and he was also sure that Yamamoto would be dead by 1940 had he remained ashore in Japan. His performance and massive popularity as a naval officer, as well as his close ties to the imperial family, kept his career afloat even as Hideki Tojo, commander of the Imperial Japanese Army, became Japan's Prime Minister in 1941. Tojo and Yamamoto were diametrically opposed: Tojo was the main proponent of the Invasion of China, of the alliance with the Nazis and Italians, and of going to war with the United States.

Image: Japanese planes attack Pearl Harbor, December 7th, 1941. The large plume of water in the dead center of the photo is a torpedo hitting the USS West Virginia (BB-48)

So how did we get here? Yamamoto was staunchly opposed to war with the U.S. yet masterminded the plan to bomb Pearl Harbor? Well, despite how he felt about the U.S. prior, at the end of the day, he still had a duty to fulfill. With Hideki Tojo and other pro-war advocates now fully at the helm of Japan's government, Yamamoto recognized that there was no preventing it at this point. His time in the U.S. had taught him the reality of what war with the U.S. would mean:

"Should hostilities once break out between Japan and the United States, it would not be enough that we take Guam and the Philippines, nor even Hawaii and San Francisco. To make victory certain, we would have to march into Washington and dictate the terms of peace in the White House. I wonder if our politicians [who speak so lightly of a Japanese-American war] have confidence as to the final outcome and are prepared to make the necessary sacrifices." - Admiral Yamamoto, circa. 1941.

Image: Americans attempt to rescue sailors from the USS West Virginia (BB-48), while its leaking oil burns. Its sinking in shallow waters allowed it to be raised and repaired, but it would not be ready for service again until late 1944.

Yamamoto was well aware that a war between the United States and Japan would result in them being outproduced and outnumbered by the Americans. With no way to avoid war now, he devised a plan that would give Japan the best chance they had of coming out on top: a surprise attack on the U.S. Pacific Fleet at Pearl Harbor, crippling any military capability for the U.S. to respond immediately and giving the Japanese time to capture outlying U.S. territories and attack the continental U.S. before they could rebuild a fleet capable of matching the IJN. It is also worth noting that Yamamoto had intended for Japan's declaration of war to be delivered shortly before the attack, but other circumstances meant it was actually delivered the day after. This almost certainly would not have changed the outcome of Pearl Harbor, but hoo-boy did it (justifiably) piss Americans off.

However, the plan didn't exactly go off without a hitch, and a massive one at that: a portion of the Pacific Fleet, including the three U.S. fleet carriers, had recently left for training exercises and their whereabouts were unknown to Yamamoto. In the end, the attack resulted in 4 U.S. battleships sunk, 4 more heavily damaged, many more ships damaged, and thousands dead, all at the cost of just over 100 Japanese planes and pilots. An undeniable victory for the Japanese, even if the U.S. carriers remained.

Image: U.S. Marines land on Guadalcanal, August 7th, 1942.

Fast forward several months to August of 1942. The attack on Pearl Harbor had left the U.S. Navy weakened, but not crippled as Yamamoto intended, primarily because of the survival of all fleet carriers, as well as the timing of new American warships entering service due to a 1939 plan that turbocharged American military shipbuilding. This enabled a hastily (poorly) planned invasion to counter the IJA and IJN on Guadalcanal, a part of the Solomon Islands just east of Papua New Guinea and northeast of Australia. From August 1942 to February 1943, both the Japanese and American forces were locked in an absolutely brutal fight that left extremely heavy casualties on both sides and saw some of the most horrifying combat conditions of the war.

Both sides were far overstretched and neither could get enough supplies through to even keep their men fed, let alone in combat, as the naval and aerial combat surrounding the island was so intense that it was too dangerous to regularly resupply the island by ship. The Americans outnumbered the Japanese but all that meant was more men were starving while sitting on the island; it was not uncommon for either side to attack the other in order to scavenge what little supplies they had, to the point that they'd often use captured weapons in order to use all of what little ammunition was left. Major ground offensives by either side were few and far between as a consequence. Of the nearly 30,000 men that died during the six month campaign, almost half died of starvation or disease.

Image: the carrier USS Wasp (CV-7) burns off Guadalcanal after being torpedoed by Japanese submarine I-19, September 15th, 1942. Wasp was so heavily damaged that she was abandoned and sunk by the USS Lansdowne (DD-486). Over a third of Wasp's aircraft were in the air at the time, which were forced to make emergency landings on the nearby USS Hornet.

Image: The blast of a Japanese bomb on the USS Enterprise (CV-6), August 24th, 1942. She was operating off Guadalcanal at the time and continued to do so after makeshift repairs.

The savage fighting on air, land, and sea had left both sides battered and bruised, but eventually the attrition of men and equipment began to catch up to the Japanese forces. The USN had finally begun to push the IJN back from Guadalcanal, and fearing their men would be cut off and encircled on Guadalcanal, the Yamamoto and the IJN organized a hasty evacuation of around 10,000 IJA soldiers, though they weren't able to evacuate all forces before being cut off. Their defeat on Guadalcanal marked the first time that the Japanese conquest over the Pacific was not only halted, but pushed back. It was a massive psychological victory for the Americans and important psychological defeat for the Japanese, though Guadalcanal's overall importance as a strategic asset was relatively minor.

I've already mentioned the costs of this campaign quite a bit, but I just want to emphasize how bad it was really was:

On the American side, the U.S. Navy kept the actual death toll and number of ships lost hidden until after the war. They believed that releasing them to the public would dampen support for the war effort.

On the Japanese side, Major General Kiyotake Kawaguchi, commander of IJA forces on Guadalcanal, said this: "Guadalcanal is no longer merely a name of an island in Japanese military history. It is the name of the graveyard of the Japanese army." Japan no longer had the men and equipment to effectively fight the United States military.

Image: Admiral Yamamoto (left, in white) addresses IJN pilots, Rabaul, Papua New Guinea, April 18th, 1943. This was taken mere hours before his death.

Alright, enough about the background, let's get to the meat and potatoes: Operation Vengeance. Following their defeat at Guadalcanal, morale in the IJN was at an all-time low. Recognizing this, and him being a sailor's sailor, Admiral Yamamoto decided to visit many of the major IJN units and installations still around the Solomon Islands and Papua New Guinea in order to help boost morale. Pretty standard military stuff, especially when you're as well-liked by your men as Yamamoto was. Problem was, the Allies had deciphered Japan's communications coding months earlier, so when Admiral Yamamoto's itinerary was transmitted, it was intercepted and deciphered by the U.S. Navy's intelligence branch. This gave them the when and the where, but now the how.

Image: U.S. P-38 Lightning's flying in formation.

This gave them the when and the where, but now the how: the Lockheed P-38G Lightning. The U.S. Navy and Marine Corps had no aircraft that would be able to fly 600 miles to intercept Yamamoto's plane and make it back without running out of fuel. Enter the P-38G: a long-range, heavily armed interceptor that was the antithesis of everything the Army wanted out of a plane pre-war, but was so successful that it was the ONLY U.S. design that was in full-scale production throughout the entire war.

My next post will be about the P-38 itself, so stay tuned!

Image: A restored P-38 in 2021, showing its unique design. Also hee-hee funny name.

So with no other choice, Naval Intelligence decided to approach the U.S. Army Air Force (USAAF) with what they'd uncovered about Yamamoto's future whereabouts. Despite British objections to the plan as the operation could easily expose that the Japanese code was broken, U.S. officials decided to move ahead with it using USAAF pilots and their P-38Gs to intercept Yamamoto's plane. They weren't going to pass up the chance to kill the mastermind behind the Pearl Harbor attack and ultimately the man responsible for the devastating U.S. Navy losses since then.

Image: the P-38 pilots who participated shortly after their return. Note that there are 17 pilots pictured, because one of the original 18 did not make it back.

A total of 18 pilots were hand-selected from multiple different P-38 squadrons to create an "A-team" of the best P-38 pilots they could find to carry out such an important mission. Four were designated to be the men who would attack Yamamoto's planes while the remaining 14 would provide cover from Japanese fighters and fill in should any of the first four not be able to carry out the mission.

On the morning of the April 18th, 1943, the men took flight from an airfield on Guadalcanal. Two of the four lead P-38's experienced mechanical failures and were replaced, leaving 16 P-38s to carry on the mission. In order to remain undetected, they flew below 50ft and maintained radio silence throughout the whole 600 mile flight, taking over two hours despite the P-38's high speed. The P-38s would not have the fuel to loiter for more than a few minutes at most, so were going to need a lot of skill to plot out where Yamamoto's planes would be and a lot of luck that they would be exactly on time. To make things even more difficult, the squadron had to fly that 600 miles with no navigation aids except compasses, meaning even a slight error in heading would have resulted in them being miles off target.

Image: A G4M1 "Betty" bomber, same type as the one used to transport Admiral Yamamoto.

At approximately 9:34am, the P-38 squadron reached the point they had calculated they would intercept Yamamoto, just one minute before they calculated they would be there. No sooner had they arrived at the intercept point had they spotted Yamamoto's planes: a pair of G4M1 "Betty" medium-bombers carried Yamamoto and his staff, while half a dozen A6M3 "Zero" fighters escorted them. Climbing from sea level to intercept them, the Americans had to rely on the P-38G's obscene climb rate. The four planes of the "kill team" immediately engaged the Japanese planes. The "kill team" consisted of Captain Thomas Lanphier, Lieutenant Rex Barber, Lieutenant Besby Holmes, and Lieutenant Raymond Hine.

Captain Lanphier turned to engage the escorts head-on while Lieutenant Barber opened fire on one of the Betty bombers. Holmes and Hine were stuck at sea level when Holmes' drop tanks failed to detach. Barber's second pass on the bomber, now behind it, resulted in a prolonged burst across the aircraft, starting from the right engine, moving across the fuselage, and ending at the left engine. The four .50 caliber machine guns and 20mm cannon on the P-38G had shredded the Betty, and its left wing snapped off just as Barber attempted to pass it, narrowly being hit. Unbeknownst to the men at the time, this was the plane that carried Admiral Yamamoto. Missing a wing, it spiraled into the ground and crashed into the jungles on the island of Bougainville in Papua New Guinea.

Image: unrelated footage of the P-38 in combat. I think you get the image though.

Back in the skies, Holmes and Hines had entered the fight after finally shaking his drop tanks lose, engaging the second Betty along with Barber. After taking a beating from the pursuing P-38s, the Betty crash-landed into the sea just off Bougainville. This Betty carried IJN Chief of Staff Vice Admiral Matome Ugaki and many of Yamamoto's staff members, but because it had managed to descend before being shot down, the crash-landing into the sea was relatively gentle and many of those onboard survived, Ugaki included. None of the escorting Zeros were shot down as the total engagement lasted just a few minutes before the P-38 squadron was forced to return or run out of fuel, and the Zeroes did not give chase as they were greatly outnumbered. All but one American pilot managed to land safely: Lieutenant Raymond Hine was missing after the scuffle, presumably either shot down or suffered a mechanical failure. With no fuel remaining, having no way to rescue him if he was found alive, and the threat of additional IJN fighters intercepting them, the squadron was forced to return to base before they could search for him. His exact fate is still unknown, he was listed as missing in action but given that he did not turn up (even after the war), it's presumed he was killed in action.

Image: What was left of the G4M1 Betty carrying Yamamoto, circa April 1943.

The aftermath: an Imperial Japanese Army search and rescue party located Yamamoto's Betty the next day and found no survivors among the wreckage. What's known is that Yamamoto was killed by two .50 caliber bullets: one hit him in the left shoulder and the other in the head, killing him instantly. It's impossible to say with complete certainty which American pilot was responsible, but it's by far most likely Lieutenant Rex Barber's attacks that killed him, based on the trajectory of the bullets and the location of where Yamamoto was determined to be sitting. Captain Lanphier was largely credited with the kill as his account was heavily embellished (he even claimed to have shot down a Zero, which he did not), but these findings definitely go against his claims and support Barber's account. This account is a little suspicious to me, but I'll let you decide: the IJA search team leader claims to have found Yamamoto thrown clear from the wreckage but still in his seat, sitting upright under a tree, with his white-gloved hand still on his katana's hilt, with his head tilted down "as if in deep thought". Sounds embellished to me, but who knows, I wasn't there and he was.

Image: Admiral Yamamoto's state funeral precession on June 5th, 1943.

Given the exact details of his death, especially the very gory details I spared you about the autopsy's exact findings of his injuries, both Japan and the U.S. were tight-lipped about the incident. The U.S. didn't want to codebreaking operation exposed, going so far as to completely shutdown Associated Press stories that contained more details than what the wider public (and Japan) knew. The Japanese also didn't want to admit that a man as important and popular as Admiral Yamamoto had been killed when his transport plane was shot down. They sealed the autopsy findings (again they were pretty gory) and tweaked the story so that the official report read that Yamamoto was "directing strategy from the frontlines" and he had "engaged with the enemy and met gallant death on a war plane." Still it was a major psychological boon for the Americans and a massive blow to the Japanese war effort. The American and Japanese public did not learn the whole story until after the war had ended and the U.S. eased up on the censorship.

That's the end of Admiral Isoroku Yamamoto's story. His wife, Reiko Mihashi (married in 1918) and four children survived the war. For additional context, I, keebs63, am an American, but if you read the first part of this post, you should hopefully understand what I'm about to say: I believe that Admiral Yamamoto, despite being on the wrong side of history, was a good man. He did not want war, but war was inevitable. This left him with two terrible options: fight in the war he so adamantly opposed or abandon his countrymen knowing they would be annihilated under anyone else's leadership. He chose to stay and give his country the best chance it had at coming out on top, which I think most people can understand and respect. I still think that the attack on Pearl Harbor was a disgusting act while also understanding and accepting why Yamamoto did it. I also understand and accept why he was killed in retribution for Pearl Harbor.

Though I'm personally fascinated by military history, I would not describe myself as being pro-war nor anti-war. War only leaves death in its wake, but sometimes you're left with little choice to avoid it. Hideki Tojo and his ilk made the choice for Japan and the United States. With a collision course set for the U.S., Admiral Yamamoto did what he could to try and soften the impact for those in his boat at the cost of those Americans in the other boat (figure of speech if you couldn't tell). Yamamoto is one of the only figures in World War II Japan that I think deserves a little respect. Unlike Yamamoto, those men who advocated for the war deserve to rot in hell.

I don't really know how else to end this long-ass train of thought so here it is: The End.