Operation Vengeance – Inside the Improbable U.S. Mission to Kill Japan’s Admiral Yamamoto

In April, 1943, American P-38s carried out one of the daring missions of the Second World War: the unlikely interception and killing of Japanese admiral Isoroku Yamamoto, mastermind of the Pearl Harbor raid. (Image source: WikiMedia Commons)

“While P-38s packed the firepower and had the range necessary to carry out the mission, the task itself bordered on suicidal.”

By Jim Stempel

AFTER A LONG day of decoding enemy intercepts, two U.S. military cryptanalysts rushed into the office of Pacific Fleet intelligence officer, Edwin Layton, and put a deciphered message in his hands. Layton’s eyes immediately lit-up. Grasping the implications of the message instantly, he leaped to his feet and darted down the hall to Admiral Chester Nimitz, Pacific Fleet Commander.

The message, received on April 14, 1943 as part of a series of radio-intercepts, was a Japanese naval communication encoded in the usual JN-25D cipher. Its contents were a potential bombshell for the U.S. war effort. Within the message were details of an upcoming flight by Admiral Isoroku Yamamoto to an airstrip on the island of Bougainville, New Guinea. Remarkably, the message contained a precise timetable of the flight, slated for April 18, indicating exactly when the admiral intended to land. It also revealed that Yamamoto and his staff would be traveling in two Betty bombers, that would be escorted by six Japanese Zero fighters. Since Bougainville was at the outer limit of the striking distance of the American airfield on Guadalcanal, the decoded report represented an intelligence jackpot.

Yamamoto was the commander-in-chief of the Japanese combined fleet. In 1941 had organized the surprise attack on Pearl Harbor. The raid had enraged the American people, and initiated war between the two countries. As a target, he was a high priority.

Isoroku Yamamoto addresses pilots of the Imperial Japanese Navy Air Service. (Image source: WikiMedia Commons)

Prior to the war, Yamamoto had studied at Harvard University (1919 – 1921), and worked in Washington, D.C. as a naval attaché. He was fluent in English and traveled widely across the United States, becoming familiar with the size and scope of the country, along with the attitudes of ordinary citizens. He was one of a handful of Japanese officers who understood that Americans, as a free people, would respond furiously if attacked.

In fact, Yamamoto was one of the few dissenting voices in Japan arguing against war, writing: “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 terms of peace in the White House.”

Yamamoto’s warning fell on deaf ears and the admiral ultimately bowed to the rapacious ambitions of the Japanese high command. He planned the successful Pearl Harbor strike, then took full command of the Imperial Navy. Once considered a friend by many Americans, by 1943 he had become a symbol of Japanese militarism, hence a target of great importance.

Nimitz signed off on an operation to shoot Yamamoto out of the sky; he asked Admiral William “Bull” Halsey to design and execute the mission. Admiral Marc Mitscher was then tasked by Halsey to orchestrate the strike.

Lockheed’s P-38 Lighting was a pre-war, twin-engine heavy fighter. In 1943, it the only warplane in the U.S. arsenal that could carry out this particular mission. (Image source: WikiMedia Commons)

The only fighter plane in the theatre capable of reaching Bougainville was the P-38 G Lightnings of the 339th Fighter Squadron, then stationed at Henderson Field on Guadalcanal.

The P-38, developed by Lockheed in 1938, was a long-range, twin-engine fighter that packed a wallop. Capable of reaching speeds of 400 mph and with the ability to climb 20,000 feet in six minutes, it was faster and more powerful than any other fighter in service. With four M2 Browning machine guns, and an auto cannon armed with 150 rounds, all mounted in the nose of the aircraft, it could destroy tanks, bunkers, pillboxes, even ships. The P-38’s unique, twin boom, centre nacelle design gave the Lightning a sleek futuristic look, and while not as nimble as some other fighters in a dogfight, at long distances it was a superb fighting aircraft, much feared by the enemy. As such, it was the perfect instrument for what had been code named Operation Vengeance.

While P-38s packed the firepower and had the range necessary to carry out the mission, the task itself bordered on suicidal. The intercept point, just west of Bougainville, was 400 miles away from the Lightnings’ airfield. Plus, an additional 200 miles would have to be added to the journey – a wide swing westward was essential to avoid Japanese radar and observation posts in the Solomon Islands. Even with a direct flight path home, the total roundtrip distance of 1,000 miles would cut dangerously close to the P-38’s maximum range, even with drop-tanks. Time for maneuver and fighting over Bougainville – the most vital aspect of the entire mission – would have to be no more than 10 minutes, a fact that greatly reduced the chances of success. In fact, Major John Mitchell, commander of the 339th, figured the odds of merely spotting Yamamoto’s flight (better yet, shooting it down) at a thousand-to-one. Nevertheless, the decoded intelligence had to be acted upon, and the flyers of the 339th were eager to supply that action.

The outward leg of the mission took the American formation from Guadalcanal in the south, out over the Solomon Sea, and then on to the target area over Bougainville. (Image source: Google Maps)

Eighteen pilots were selected for the mission: four specifically assigned to attack the two bombers, while the others would provide cover and drive off the Japanese escorts. Two additional P-38s were added as backups should any of the first 18 planes develop mechanical problems en route. The four pilots selected for the killer group were Captain Thomas Lanphier, Jr., Lt. Rex Barber, Lt. Jim McLanahan, and Lt. Joe Moore.

The Lightnings departed Guadalcanal at 7:10 a.m. April 18, Major Mitchel leading them out over the Coral Sea. Mitchell had meticulously calculated each leg of the flight. If everything went as planned, the pilots hoped to spot Yamamoto’s flight 10 miles west of Bougainville at precisely 9:35 that morning. To avoid any detection by Japanese radar, the planes flew dangerously low, just 50 feet above the waves.

Mitchell took the lead, the four “killer craft” directly behind him, the remainder fanning-out still further behind them. Mitchell recently had a navy compass installed in his cockpit, and between the compass, his watch, and his plane’s speedometer, he carefully checked-off each leg of the flight, hoping to arrive at the estimated kill point at exactly 9:35 a.m. In a world long before computers, it was brains, skill, and guts that would guide the mission.

Unfortunately, both Mclanahan and Moore of the strike group immediately developed mechanical problems and had to drop out of the formation. They were replaced at once by the two spares, these piloted by Lt. Raymond Hine and Lt. Besby Holmes.

Then, some 20 miles west of Bougainville, Group Leader Mitchell dipped his wings, signalling for the final turn, and the entire flight banked toward the northeast. The Lightnings, still obscured in a low, morning mist, climbed to attack altitude. Minutes later, the flight emerged from the mist into a clear blue sky with the green mountains of Bougainville now plainly in view.

But it was 9:34 – the American planes had arrived one minute early. The sky in all directions appeared empty of enemy aircraft. Then, one of the pilots in the covering group called out over the radio, “Bogeys! Eleven o’clock high!”

A Japanese Betty bomber.

All heads snapped in that direction. And there they were: two Japanese bombers accompanied by a protecting flight of six Mitsubishi Zeros. All the enemy planes were descending toward the airstrip, exactly as scheduled. Operation Vengeance had located its needle in a haystack.

Mitchell immediately radioed Tom Lanphier to take on the Zeros. “All right, Tom,” he cried, “Go get him.”

Lanphier barrelled straight for the Zeros, but Holmes had trouble dropping his wing-tanks, and had to veer-off. Hine likewise peeling-off behind Holmes. This left Lanphier momentarily alone; it didn’t matter. Ignoring the odds against him, Lanphier went straight at the Zeros. He attacked the fighters head-on, spraying them with the full weight of his machine guns and cannon, instantly scattering their dive.

Meanwhile, Rex Barber zeroed-in on one of the bombers, which, having spotted the American fighters, was desperately diving to escape. It crossed in front of him, but Barber was able to turn, then bank out of a roll, coming-up directly behind the descending target – in perfect attack position. Then he cut loose with everything he had.

Just then, Lanphier – also turning and spotting the same bomber himself – fired from long distance, scoring a hit. Simultaneously, as Lanphier was firing, Barber closed in and riddled the enemy aircraft at close range until pieces of metal flew everywhere. Smoke and flames engulfed the bomber, and Barber watched as the flaming plane turned, then crashed into the jungle canopy below in an enormous ball of fire. One down, one to go.

Unknown to the pilots at the time, the bomber they had just downed was the one carrying Yamamoto. He would later be found in the jungle by a Japanese search party, still strapped into his seat with two bullets holes in his body. He was killed instantly before his plane had exploded upon impact. A debate would rage for some time as to whether it had been Barber, Laphier, or both who deserved credit for the kill.

The crash site of Yamamoto’s downed Betty bomber. (Image source: WikiMedia Commons)

Barber then had to turn, fleeing pursuing Zeros that were suddenly on his tail, but spotted the other Japanese Betty bomber, also frantically trying to evade pursuit. As the covering Lightnings took on the Zeros, Barber, Holmes (who had shaken loose his wings tanks), and Hine banked and accelerated, chasing the bogey out over the ocean. Closing-in, all three opened fire, tearing the plane to shreds in seconds. They all watched as it disappeared into the waves below, consumed in flames.

The second Betty carried Yamamoto’s chief of staff, Vice-Admiral Martome Ugaki. He, along with two others, survived both the attack and crash, and would later be picked-up by a Japanese rescue party. But for the Americans, the downing of both bombers meant success. With their fuel running low, it was time to turn for home.

“Mission accomplished,” Mitchell called out, watching as the second bomber went into the sea. “Everybody, get your ass home!”

With that, all the Lightnings banked and headed toward Guadalcanal, 400 miles away. Their tanks were nearing empty, but all the pilots were ecstatic over what they had accomplished. One plane, running dangerously low on fuel, was forced to land at a forward airbase in the Russel Islands, while Hine, possibly shot by a Zero and trailing smoke, was never heard from again.

All the remaining American fighters made it safely back to Guadalcanal’s Henderson Field before noon, Barber’s P-38 sporting over 100 machine gun holes throughout its airframe. So ended one of the most remarkable and daring military missions of World War II.

The Japanese high command, staggered by the loss of their most talented admiral, withheld information about Yamamoto’s death for more than a month. Officials feared how citizens, who for years had been fed a steady diet of upbeat propaganda, would take the news.

Although the 1942 Battle of Midway had crippled the Japanese fleet, after Yamamoto’s death, the Japanese high command would preside over an ever-worsening war effort. Yet despite this, they remained undeterred. Nurtured on the code of bushido, the high command would fight on blindly for two more ghastly years until – as one historian wrote – “Japan would lay in ruins, and two million of her sons and daughters would be dead.”

Jim Stempel is a speaker and author of nine books and numerous articles on American history, spirituality, and warfare. His newest book regarding the American Revolution – Valley Forge to Monmouth: Six Transformative Months of the American Revolution – will be released in November and is currently available for pre-order on virtually all online sites. This serves as a follow-up to his critically acclaimed book American Hannibal, an examination American General Daniel Morgan at the Battle of Cowpens. Visit his website JimTemple.com for all his books, reviews, articles, biography and interviews.

4 thoughts on “Operation Vengeance – Inside the Improbable U.S. Mission to Kill Japan’s Admiral Yamamoto

  1. Vengeance is sweet.
    Yamamoto knew that if the Americans would not sue for peace shortly after Japan attacked Pearl Harbor it would just be a matter time for Japan to loose the war.

  2. I may have missed it, but I did not see in this article what I read some place else: that one of the problems the U.S. faced was trying to make sure that the Japanese did not infer from the mission that we had broken their military encryptian code.

    As an inspiring story of amazng complexity it is perhaps at the same level as Operation Black Buck in the Falklands War to neutralize the Port Stanley Airport.

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