Operation Vengeance: Mission to Kill Admiral Yamamoto

By Tom Laemlein

Posted in
#History

In the early days of the United States’ involvement in World War II, stateside motivational posters proclaimed, “Remember Pearl Harbor”, and “Avenge December 7^th”. And while the “date which will live in infamy” focused America’s rage on Imperial Japan, U.S. military planners in the Pacific Theater of Operations (PTO) dreamed of vengeance against the specific planner of the Pearl Harbor attack: Admiral Isoroku Yamamoto.

While the P-38 Lightning also served in Europe, it played an outsized role in the Pacific during World War II including being part of the daring mission to kill Yamamoto. Image: DVIDS

Yamamoto, the commander-in-chief of the Japanese Combined Fleet, had originally been opposed to war with America, and had made his feelings known privately and even publicly. He warned that he believed Japan could not defeat the United States, as Japanese production could never match up against American industrial might. Even so, political pressure and his sense of duty led him to plan the daring first strike against America’s prime naval base in the Pacific.

Black-and-white photograph of several Lockheed P-38 Lightning fighter planes flying in tight formation over the Southwest Pacific in April 1943. The aircraft are seen from above, their twin-boom design clearly visible against the backdrop of clouds and ocean. These long-range fighters had been recently introduced to the Pacific theater and were already proving decisive in air superiority battles. The formation flight demonstrates how U.S. Army Air Forces organized coordinated missions, often sending entire squadrons on interception or escort duty. By spring of 1943, the P-38 was one of the only Allied fighters capable of reaching deep into Japanese-controlled areas. The aircraft in this photo likely belonged to units later involved in Operation Vengeance. — A formation of P-38 Lightnings assemble in the southwest Pacific in April of 1943. Image: NARA

By April 1943, Yamamoto’s prediction was proving correct. Japan was locked in a deepening war of attrition with America, and the situation was turning against the Rising Sun. U.S. forces were advancing in the Solomon Islands, more and more Allied equipment was arriving every day, and the United States Army Air Forces (U.S.A.A.F.) and United States Navy were beginning to achieve air superiority in some areas. The Japanese Mitsubishi A6M “Zero” fighter, while still dangerous, was no longer dominant. The tide was clearly turning.

The Breakthrough

After the efforts of U.S. Navy code-breakers paved the way for the “Miracle at Midway” in early June 1942, the signals monitoring and cryptographic intelligence unit kept at their detective work. On April 14, 1943, the U.S. naval intelligence operation, codenamed “Magic”, picked up an important Japanese naval transmission.

A P-38 is shown here being fueled for a mission at Henderson Field in Guadalcanal. Image: NARA

Once deciphered by Tech Sergeant Harold Fudenna, the message yielded the precise itinerary of Admiral Yamamoto’s upcoming inspection tour of bases in the Solomon Islands.

On April 18^th, the Admiral and key members of his staff would fly from the massive Japanese naval base at Rabaul (at 06:00 Tokyo time) and arrive at Balalae Airfield near Bougainville (at 08:00 Tokyo time). Yamamoto and his entourage would travel in a pair of Mitsubishi G4M bombers while escorted by six Mitsubishi A6M Zero fighters.

Formal wartime portrait of Admiral Isoroku Yamamoto, one of Japan’s most influential naval leaders during the Second World War. He appears in dress uniform with decorations, reflecting his senior rank and service. Yamamoto had studied in the United States earlier in life and understood the scale of American industry, yet still led Japan’s fleet into conflict. His planning of the Pearl Harbor attack made him a primary target for U.S. forces. Operation Vengeance in April 1943 specifically sought to eliminate him after his travel schedule was decrypted. His loss deprived Japan of its most skilled strategist and boosted American morale. — The target of Operation Vengeance — Admiral Isoroku Yamamoto. Image: NARA

Known to the Allies under the code name “Betty”, the G4M that would be carrying Admiral Yamamoto was not a transport aircraft but rather a land-based medium bomber of the Imperial Japanese Naval Air Service.

The Mitsubishi G4M (Type 1) attack bomber had been in service for two years at the time of the Yamamoto mission and was much prized for its long range — 1,500 miles when carrying a bomb load, and up to 2,700 miles on a ferry mission. But the great range came at a price, and throughout its career the G4M was dogged by its light construction that allowed it to be easily damaged and ignited by gunfire.

Archival image of the Japanese Mitsubishi G4M bomber, known by the Allied reporting name “Betty.” The aircraft is shown on the ground with its full wingspan and narrow fuselage clearly visible. Designed for long-distance missions, it was heavily used by the Imperial Japanese Navy Air Service throughout the Pacific War. Its light construction meant that it could fly farther than most bombers of its time, but at the cost of crew protection and survivability. Pilots and crews were vulnerable to Allied fighters, which frequently set these planes ablaze during combat. The G4M that carried Admiral Yamamoto was ambushed and destroyed during Operation Vengeance in 1943, cementing the aircraft’s role in history. — Shown is the Mitsubishi G4M “Betty,” the type of aircraft carrying Yamamoto during the interception by the Lightnings. Image: Author’s Collection

Early models lacked self-sealing fuel tanks, and Allied pilots called the Betty the “Type 1 Lighter” or “The Flying Zippo”. There was little or no armor protection for the crew, the fuel tanks or the engines.

Even so, the G4M squadrons had their share of success in the first year of the war, including the participation in the destruction of the battleship HMS Prince of Wales and the battlecruiser HMS Repulse in December 1941, along with the heavy cruiser USS Chicago in January 1943.

Seizing the Moment

At first, American intelligence officers had a hard time believing that the Japanese would be so cavalier as to transmit such a message, even if it was encoded. But additional code-breakers stationed in Alaska and Hawaii also intercepted that message, deciphering it to reveal the same details.

Black-and-white photograph of a Lockheed P-38 Lightning, highlighting its distinctive twin-boom tail and central nacelle cockpit design. The plane was unlike any other Allied fighter of the era, built for long-range missions and capable of carrying heavy firepower. Four .50 caliber machine guns and a 20mm cannon were mounted in the nose, giving it concentrated striking power. The twin-engine layout provided both speed and endurance, allowing it to escort bombers and intercept enemy aircraft far from base. Pilots praised its ruggedness, even though the engines were sometimes vulnerable. Its unique silhouette made it easy to identify in the air. The P-38 became famous for its role in Operation Vengeance and other Pacific missions. — The P-38 was a uniquely designed plane with twin tails, impressive range and incredible firepower. Image: NARA

The significance of this intelligence windfall would have been hard to overstate. U.S. armed forces had ample motivation to remove one of Japanese most important chess pieces from the board, and Admiral Nimitz made the call. He judged that the opportunity to terminate Yamamoto and seriously damage the Japanese navy, as well as Japan’s overall morale, was worth the risk of tipping off the enemy that their codes had been broken.

As a code name, “Operation Vengeance” seemed fitting for the mission. Vengeance was clearly on everyone’s mind among America’s military and political leaders. The pain of Pearl Harbor was still fresh, and Admiral Nimitz received permission to proceed from Secretary of the Navy Frank Knox.

Once cleared on the mission, Admiral Nimitz reached out to Vice Admiral William “Bull” Halsey, commander of the South Pacific Area. It was soon determined that there was only one American interceptor that was truly capable of performing this mission, and it was relatively new to the Pacific theater. That plane was the Lockheed P-38 Lightning.

Halsey immediately called upon the U.S.A.A.F. 339^th Fighter Squadron based at Henderson Field, Guadalcanal, to handle the interception. Detailed plans for the mission were calculated and mapped out immediately. Vengeance was soon to come, and the Lightning would play an integral part in the mission.

The Right Tool

The P-38 became operational with the 5^th Air Force in early March 1943. In that same month, the U.S.A.A.F. prepared a report titled “Tactical Suitability of the P-38F Airplane”, which contained the following information that would be of critical importance during the mission to intercept Yamamoto.

Black-and-white photograph of a Lockheed P-38 Lightning parked on an airstrip at Guadalcanal during World War II. The fighter’s distinctive twin-boom design is visible against the rough, improvised runway surface common to Pacific bases. Ground crew and equipment can be seen nearby, reflecting the constant maintenance needed in tropical conditions. Guadalcanal served as a forward operating base for the U.S. Army Air Forces, allowing P-38s to fly long-range interception and escort missions. It was from this island that the fighters launched the April 1943 Operation Vengeance mission against Admiral Yamamoto. The image highlights both the rugged conditions and the strategic role of Guadalcanal in the Pacific campaign. — A P-38 Lightning sits on an airstrip at Guadalcanal, one of the key Allied bases in the Pacific. From here, long-range missions like Operation Vengeance were launched. Image: U.S. Marine Corps

“The visibility over the nose is satisfactory for deflection shooting, but the armor plate window and gunsight obstruct the forward vision for search. To the sides, the view downward is limited by the position of wings and engines, and searching below will have to be accomplished by banking the airplane from side to side. The search view on both sides is greatly obstructed by metal strips where the canopy joins the window. The view to the rear is limited by the boom and rudders, and rear armor plate.”

One of the men who would play a prominent role in the mission, Captain Thomas Lanphier, was interviewed after the mission for a confidential article in a Bureau of Aeronautics publication. The following excerpts provide some insight into how the P-38s were used in their early deployment, and what the combat pilots thought of them:

“P-38s are rugged, they take a lot of punishment. Apparently, they’re vulnerable only in the engine. The pilot is pretty well protected. The Japs thought the P-38s were the best planes they were running into.

Archival wartime image of the nose and wing of a Lockheed P-38 Lightning, focusing on its weapons and additional fuel capacity. The aircraft’s five-gun armament, with machine guns and a 20mm cannon clustered tightly in the nose, provided devastating forward firepower. An external drop tank is mounted under the wing, a common addition for missions that required extreme range. The design eliminated the need for wing-mounted guns, giving the Lightning superior accuracy at long distances. This loadout was crucial in the Pacific, where fighters often flew hundreds of miles over open water. The image illustrates both the offensive and endurance-oriented features of the aircraft. — The twin-boom Lockheed P-38 Lightning showing its five-gun nose armament. Image: NARA

“The firepower, four .50-cal. Machine guns and a 20mm cannon, is quite satisfactory. The cannon uses all explosive ammo. The four .50s flying right straight up made a splendid concentration of firepower.

“When … (new pilots) … have flown the planes and learned how stable they are, how well the pilot is protected, what a lot of damage can be dealt out with them — in other words, once they get on a flight — they’re okay. It doesn’t take very long for the ordinary American kid to catch on.”

Regarding Japanese fighter tactics, he had the following to say:

“The Japanese continue to fly as they always have, react the same way to an attack, and do the same fundamental things. I’ve never run into one who, when attacked from behind, would cut his throttle. Their planes, I should think, would stop abruptly if they’d cut the throttle and we’d overshoot them. Some of them are smart enough to pull off to the side, but that is usually taken care of by our wingman. Generally speaking, they still pull right up in the air, or roll upside down and go straight down, which puts them out of the fight. The Japanese pilots coming over are not so smart as they used to be; they are probably running into the dregs now.”

Black-and-white close-up photograph of a U.S. Army Air Forces soldier loading film into the gun camera of a P-38 Lightning fighter. The camera is mounted near the aircraft’s nose guns to capture combat footage during aerial engagements. The serviceman carefully threads the film, ensuring it will function during the next mission. Gun cameras were vital for confirming air-to-air victories, reviewing tactics, and providing training material. The image highlights the behind-the-scenes work of ground crews, whose efforts ensured accurate combat records. Such preparations were crucial during missions like Operation Vengeance. — Loading the P-38’s gun camera with film. The fighter’s 20mm cannon is mounted in the lower center, with four .50 caliber MGs arrayed above. Image: NARA

On P-38 tactics against Japanese fighters, he stated the following:

“I had a four-plane section which had flown together for about a year, which is unusual for the Army. Each of us felt very responsible for the others; I was responsible for my wingman, and he was for me. We never had occasion to use any evasive maneuvers; we were never surprised from behind. We had planned that if we were completely surprised and had to get out in a hurry, we would pull off in a dive and scissor the way naval aviators do in the dive, except we would endeavor to pull off sideways and back. We try to stay in a ball within a mile area, each keeping his wingman in sight.

“The leader, being the ranking man, has the first chance to shoot. The wingman, although he also wants to shoot down enemy planes, suppresses that desire until the leader has taken care of his target. Then it is the wingman’s chance, with the leader protecting him. We operate that way — just two fellows working together. It is the leader’s responsibility, however, to keep the two pairs of planes in proximity to each other.”

When asked if he goes head-on against Zeros:

“I only got two head-on passes. If the Zeros saw there was a chance of us getting around them, they’d turn and go off. We couldn’t seem to get them to tangle with us. The P-38 is a very maneuverable plane despite its size.”

Black-and-white wartime photo of a Mitsubishi G4M bomber in flight, known by its Allied code name “Betty.” The aircraft has a long, narrow fuselage and twin engines, optimized for range but lacking protective armor. Its light structure and unprotected fuel tanks made it extremely vulnerable in combat, often bursting into flames when hit. Japanese crews nicknamed it “Hamaki,” meaning cigar, while Allied airmen referred to it as “the flying lighter.” Despite its flaws, the G4M was heavily used in the Pacific theater for bombing and transport roles. The aircraft’s reputation for catching fire overshadowed its otherwise impressive range and speed. — The Mitsubishi G4M was prone to catching fire. The Japanese called it “Hamaki” (cigar), and Allied pilots nicknamed it “the flying lighter”. Image: NARA

Regarding new pilots, he had this to say:

“New pilots are very cocky and independent when they first arrive. For instance, a big ex-All-American football star looks at the combat pilot to whom he has been assigned for training and asks: ‘That little bird, what does he know? Am I supposed to follow that little weasel?’ Some of the most experienced pilots have ‘baby faces’ and quiet manners, which seem incompatible with their exploits.”

When asked about the P-38’s maneuverability in combat, Lanphier stated:

“We had some trouble fighting Zeros. We can’t turn and approach as fast as they can. Some of us used our flaps and slowed up, staying behind the Zeros when they turned and then turning underneath them. That was frequently effective. If we had planned an attack on bombers, I think I would have my people dive with the flaps (making an overhead approach and using the flaps to keep slow until making a run), then fold the flaps and dive. We can turn inside the Grumman with the flaps.”

Lightning Strikes

So, it was determined what plane would perform this mission, and the men who would fly them. However, distances and hurdles involved in pulling off such a daring mission were extremely daunting.

In a straight line, the range from Guadalcanal to Bougainville was 400 miles. However, there were several Japanese radar stations in the area, plus plenty of coast watchers ready to identify inbound American aircraft and sound the warning. Postwar investigation showed that several Japanese officers at Rabaul strongly advised the admiral to call off his inspection tour — fearing an American attack. Regardless, Yamamoto kept to his schedule.

U.S. military diagram detailing the flight patterns of Operation Vengeance, the mission to kill Admiral Isoroku Yamamoto. The chart shows the route of the Japanese bombers and escorting Zero fighters alongside the American P-38 intercept course. Complex arrows and path markers outline how the P-38s flew low over the ocean to avoid detection before climbing into attack position. The point of interception near Bougainville is clearly marked, where Yamamoto’s G4M was destroyed. This type of visual planning tool was used to brief pilots on exact timing, positioning, and engagement strategies. The diagram is both a tactical record and a historical document of one of World War II’s most famous aerial ambushes. — This USAAF diagram of the Yamamoto interception illustrates the interception of the Japanese aircraft by the P-38 Lightnings. Image: NARA

Major John Mitchell, leader of the mission, plotted an interception course that would take the 339^th Squadron P-38 fighters out to sea and then back again, to emerge over Bougainville as the admiral arrived at 9:35am. The circuitous route would total 1,000 miles: 600 miles on the outward leg (at about 50 feet over the water), and 400 miles for the return flight. Extra fuel was allocated for the expected dogfights.

To make sure the P-38s had enough avgas, one of the two standard 165-gallon external fuel tanks was replaced with a 330-gallon tank. Despite the unbalanced weight in the P-38’s midsection, the fighters flew without problems.

A total of eighteen P-38s would carry out the mission, with four of them designated as the “Killer Flight”. Major Mitchell and the other 13 Lightnings would fly top cover, prepared to fight off the expected Japanese escort fighters. The plan called for the killer flight to consist of Lieutenants Thomas Lanphier, Rex T. Barber, Jim McLanahan and Joe Moore.

Black-and-white photograph of First Lady Eleanor Roosevelt examining the wreckage of a Japanese Mitsubishi A6M Zero fighter shot down on Guadalcanal. She is dressed in civilian attire, standing beside damaged aircraft parts as U.S. personnel look on. The image captures her historic wartime visit to the South Pacific, where she met with troops and inspected battlefields. The destroyed Zero symbolizes the fierce aerial combat that took place during the Guadalcanal campaign. Roosevelt’s presence on the island was both symbolic and morale-boosting, demonstrating the home front’s connection to the front lines. The photo highlights her unique role as an active First Lady during World War II. — First Lady Eleanor Roosevelt inspects the wreckage of a Japanese Zero shot down on Guadalcanal. Zero fighters were a formidable aircraft that guarded Yamamoto. Image: NARA

Troubled brewed early, as McLanahan did not make the flight with a flat tire, and Moore dropped out with a fuel line problem. Lieutenants Besby Holmes and Ray Hine moved in to take their places. After this initial complication, everything went completely to plan.

On April 18, the P-38s took off from Kukum Field at 07:25, Guadalcanal time. Major Mitchell’s dead reckoning navigation was outstanding. The Lightnings reached the interception point about a minute early (at 09:34) and immediately saw the two G4M bomber/transports descending through a light haze. The P-38s jettisoned their tanks, turning and climbing into the bombers.

Thomas Lanphier and Rex Barber turned in behind the diving G4M bombers. The four Browning .50-cal. AN/M2 machine guns and 20mm M2 cannons in the Lightnings’ central nacelles tore apart the first Betty’s right engine and sent shells crashing the length of the bomber’s fuselage. The plane suddenly flipped over and, when Barber looked over his shoulder, he saw a smoke trail that terminated in the Bougainville jungle. This Betty turned out to be Yamamoto’s plane.

At that moment, the second bomber was low over the water near Moila Point, under the guns of Besby Holmes and Ray Hine. Both pilots scored some hits on the Betty, but their speed carried them past the target. Rex Barber dove and picked up the chase, and he also scored some hits on the second bomber, which soon bellied into the water at high speed. Remarkably, Yamamoto’s Chief of Staff, Vice Admiral Matome Ugaki and two other passengers survived the violent crash and were rescued.

U.S. Army Air Force reconnaissance photograph showing the wreckage of Admiral Yamamoto’s Mitsubishi G4M bomber on Bougainville in April 1943. The aircraft lies broken in the jungle, with debris scattered among the trees. This reconnaissance image confirmed that the mission to intercept and destroy Yamamoto’s transport had succeeded. The bomber’s remains are barely distinguishable against the dense vegetation. U.S. intelligence used photos like this to verify claims from pilots and to record significant operations. The crash site became both a battlefield relic and a symbol of Operation Vengeance’s success. — U.S. Army Air Force reconnaissance photo of Yamamoto’s G4M crash site on Bougainville. Image: NARA

By this point, the Japanese escort fighters were on the scene and Rex Barber’s and Ray Hine’s P-38s received damage — but all the Lightnings exited the interception area. A Navy PBY Catalina patrol plane encountered Ray Hine on his trip home. The PBY noted his damaged P-38 (one engine feathered) and offered to pick up the pilot if he preferred to ditch. Hine asked for a compass bearing and headed towards Guadalcanal. Unfortunately, he never arrived, and no trace of his aircraft was ever found. He was the only American lost on the mission.

As for Admiral Yamamoto, a Japanese search party found his body near the crash site of the first Betty downed — thrown clear from the wreck but still in his aircraft seat, his hand on the hilt of his katana. He had been hit twice, once in the back of the shoulder and once in the head. The Japanese coroner on the scene concluded that Admiral was probably dead before the Betty hit the ground. Japanese media reported that he “met a gallant death aboard a warplane”.

The Kill Controversy

When Thomas Lanphier returned to Guadalcanal, he announced over a clear-channel radio frequency “I got Yamamoto!” as he entered the landing pattern. This was a major breach of communications security and in violation of standard procedures. Many of the other interception flight pilots reported that they heard him make the claim over an open line.

photograph showing Captain Thomas G. Lanphier, Jr. receiving the Distinguished Flying Cross and Silver Star after Operation Vengeance in 1943. Lanphier stands in uniform as he is presented with decorations recognizing his role in the interception of Admiral Yamamoto’s aircraft. The ceremony underscores how important the mission was to U.S. military leadership, both strategically and symbolically. Lanphier was one of the P-38 Lightning pilots who participated in the ambush over Bougainville. Although later historical reviews questioned his exact role in Yamamoto’s shootdown, he was publicly honored at the time. The photo captures the official recognition of one of World War II’s most famous aerial missions. — The Distinguished Flying Cross and Silver Star being awarded to Captain Thomas G. Lanphier, Jr. after the successful completion of Operation Vengeance. Image: NARA

It was Lanphier who wrote the Fighter Interception Report, which described his own actions in glowing terms as being involved in the shootdown. It however did make specific mention that Rex Barber was involved in shooting down a Betty bomber. While the report mentioned the downing of three of the Zeros (one claimed by Lanphier as well), Japanese records show no losses among their escort fighters — just the two G4M bombers downed.

Color World War II propaganda poster showing a caricature of Admiral Isoroku Yamamoto dictating peace terms to the Americans. The exaggerated illustration portrays Yamamoto as overconfident and threatening, designed to stir anger and determination among the U.S. public. Wartime posters frequently used enemy leaders as symbols of tyranny and aggression. Yamamoto was singled out as the mastermind of the Pearl Harbor attack, making him a natural target for propaganda. The poster reflects how the U.S. government framed Japan’s leadership as dangerous and ruthless. Later, his death in Operation Vengeance was celebrated as a direct rebuttal to this image of dominance. — U.S. propaganda posters depicted Admiral Yamamoto as a looming threat to American freedom. As the architect of Pearl Harbor, he was an easy target of such messaging. Image: NARA

Kill claims have been frequently disputed since the beginning of air-to-air combat. The Yamamoto interception has been reviewed in detail several times since the war, and most of the evidence points to Rex Barber as the pilot who was responsible for taking down Yamamoto. All the pilots in the killer flight received the Navy Cross.

Thomas Lanphier was a skilled and experienced combat pilot, and whether he actually did or simply believed he shot down Yamamoto makes no difference in the final equation. The architect of the Pearl Harbor surprise attack, the day that would live in infamy, was dead. Operation Vengeance was a success.

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