World War II Database

Contributor: David Stubblebine

ww2dbaseOperation Vengeance is the name given in 1965 to a hastily planned and executed, but successful, American operation in 1943 to eliminate the commander-in-chief of the Japanese Navy's Combined Fleet, Admiral Isoroku Yamamoto. The operation started with a fortuitous intelligence operation.

ww2dbaseIntelligence

ww2dbaseIn the early morning hours of 14 Apr 1943 Hawaiian time, 15 Apr 1943 Rabaul time, a coded Japanese naval message originating from Rabaul in New Britain was intercepted by American listening stations in the Pacific. The message immediately stood out from other intercepts because of the number of addressees. The message was then repeated in an older Japanese Army code that was even less secure. Decryption efforts were begun at all of the United States Navy's codebreaking centers from Australia to Hawaii to Alaska and even Washington, DC. At Station Hypo, the Navy's interception and decryption center in Hawaii, Marine Major Alva B. "Red" Lasswell took the lead in decoding the message. Lasswell, one of the Navy's best cryptanalyst-linguists, worked through the night and by the following day, he was able to deliver a complete translation to the fleet intelligence officer, Commander Edwin Layton.

ww2dbaseThe message contained a down-to-the-minute timetable for a trip Admiral Yamamoto would be taking on 18 Apr 1943. The trip was scheduled to bring the Japanese admiral from Rabaul to the Shortland Islands just south of Bougainville in the Solomon Islands. These were the Japanese most forward areas and, therefore, the closest Yamamoto would ever be to American forces. The message indicated the trip would take place roughly 72 hours after the message was sent. By the time Layton saw it, only about 64 hours remained.

ww2dbaseDecision Making

ww2dbaseLayton immediately discussed the message with Admiral Chester Nimitz, commander of the United States Pacific Fleet. After reading the decrypt, Nimitz asked Layton, "Do we try to get him? Would the Japanese be able to replace him with someone better?" Layton, who had known Yamamoto personally while serving as a naval attaché in Tokyo, told Nimitz that no other Japanese admiral held the same stature among the Japanese people, had the naval experience, possessed the imaginative thought, or had the leadership charisma of Yamamoto; the Japanese Navy had no one as good. The loss of Yamamoto, Layton felt, would be a major blow to the Japanese ability to wage a naval war.

ww2dbaseNimitz checked with Washington, where the message had also been cracked and was being discussed at the highest levels. The discussion included a pause to reflect on whether a targeted strike against a specific individual such as a fleet commander constituted a legitimate military objective, with most believing that it absolutely did. Then the principal question became whether such a mission would jeopardize the secret that the Japanese codes had been broken, and opinions on this point were mixed. President Franklin Roosevelt was not in Washington when the matter came up and there is no surviving documentation that he was consulted, but he almost certainly was. Secretary of the Navy Frank Knox gave Nimitz authorization to proceed, but afterwards Knox always maintained that the final decision had been left up to Nimitz. Following his own careful deliberations, Nimitz gave the order to "Get Yamamoto."

ww2dbasePlanning

ww2dbaseThe task then fell to Admiral William Halsey, who was at the time commander of Allied South Pacific forces. The written orders from Nimitz had been drafted by Layton. They ended with "... provided all personnel concerned, particularly the pilots, are briefed that the information comes from Australian coast watchers near Rabaul." This was intended as a cover story to protect the strict secret that the Japanese codes had been compromised. Nimitz added the handwritten words "Best of luck and good hunting" to the bottom of the order and signed it.

ww2dbaseUpon receiving his orders, Halsey called in Admiral Marc Mitscher, commander of air operations in the Solomons, and his other aviation leaders to begin planning. Yamamoto's itinerary would not bring him within range of any of the Navy's fighters so Mitscher also consulted with the Army. The P-38 Lightning was the only American fighter in the region with the range needed for the nearly 1,000-mile round trip. The three P-38 squadrons on Guadalcanal had recently built up their compliment of Lightnings and with Mitscher's added "juice," they received in one day the external drop tanks they had been waiting for several weeks to arrive through channels. The 339th Fighter Squadron commander, Major John Mitchell, was assigned to lead the mission.

ww2dbaseAccording to the intelligence, Yamamoto's travel plans were to fly from Rabaul to Ballale Island (now Balalae) in the Shortland group south of Bougainville, then travel to Shortland Island by subchaser, return to Ballale by subchaser, fly to Buin on southern Bougainville, and then fly back to Rabaul all in a single day. Mitscher and his staff discussed with the Army pilots what their best option was for intercepting Yamamoto. The Navy men thought attacking the slow moving subchaser might offer them the best opportunity. They described their ideas in nautical terms such as attacking from the "port quarter" and similar jargon. This caused Army Major Mitchell to blurt out, "Port quarter? What does that mean? I don't know the difference between a subchaser and a sub. What if there are several boats, how do we tell them apart? What if the guy can swim? We're fighter pilots. We should take him in the air!" With that, Mitscher settled the matter saying, "He's right, we get him in the air." Before leaving the meeting, Mitchell also asked Mitscher to provide a naval ship's compass to be mounted in his airplane for better navigation over water. The mission would take place the following day.

ww2dbaseMitchell then had his own sleepless night as he and members of Mitscher's staff worked out every detail of the mission. Mitchell's P-38s were part of the "Cactus Air Force" based at Kukum Field on Guadalcanal, 350 miles southeast of their objective of Ballale Island. To achieve surprise, the plan was to fly the outbound leg at wave-top level well out to sea on a course southwest of the Solomon Islands. This route measured 540 miles one-way and, with a direct flight back to base, would make the total flying distance nearly 900 miles. The outbound leg at low altitude would also consume fuel at a faster rate so the fuel calculations became critical. Each P-38 was to be fitted with two drop tanks for extra fuel, one standard 165-gallon tank and one oversized 330-gallon tank, more than doubling the normal fuel load. The differing weights of the tanks coupled with the uneven drag they produced would impact the aircraft's handling characteristics, but the attachment points were so close to the airplane's center-line that the effects would be manageable. Even so, the fuel calculations indicated there would be no more than 10 minutes for loitering at the intercept point and the combat combined.

ww2dbaseMitchell gathered the best eighteen pilots from all three squadrons at Kukum Field and briefed them on the final plan. Mitchell separated the assignments into a four-airplane "hunter" group that would carry out the actual attack and a fourteen-airplane "cover" group. The cover group also had two "spares" factored in. The most experienced combat pilots from all three squadrons were selected as the "hunters." Mitchell would lead the mission and fly with the cover group.

ww2dbaseNone of the Army pilots were expressly told their target was Yamamoto, only that it was a Japanese "VIP." They may have been unofficially informed of the VIP's identity or a rumor may have popped up that it was Yamamoto, but they all seemed to understand who they were after. The cover story about the Australian coast watcher was fed to the pilot's as instructed, but there also seemed to be a fairly clear understanding among them that the news came from the codebreakers.

ww2dbaseHalsey and Mitscher started planning for more long-range P-38 raids to the Shortland Islands in the days immediately following the Yamamoto mission in order to sell the idea that the Yamamoto mission was just a lucky stroke among a series of routine raids. This too was designed to protect the codebreaking secret. Due to the haste required to plan and execute the primary mission, however, the pilots were never told all these nuances of the larger plan.

ww2dbaseMission

ww2dbaseThe mission was set for Palm Sunday, 18 Apr 1943, one year to the day after the Doolittle Raid and 168 years to the day following Paul Revere's midnight ride. Admiral Yamamoto's twin-engine Mitsubishi G4M1 "Betty" bomber took off from Rabaul on time at 8:10 AM local time. His chief of staff, Admiral Matome Ugaki, flew in a separate G4M bomber. For the flight, both men wore the khaki-green uniforms of the Japanese Army. The two bombers were escorted by six Mitsubishi A6M Zero fighters. There was nothing remarkable about their departure from Rabaul, unless it was that they took off precisely on schedule; Yamamoto's fastidious punctuality would work against him this day.

ww2dbaseThe decrypted Japanese message indicated Yamamoto was due to arrive at Ballale at 9:45 AM. In order to intercept Yamamoto ten minutes before his scheduled landing time as his bomber was descending, Major Mitchell's calculations determined his P-38s should take off from Guadalcanal at 7:25 AM. With 3,000 pounds of extra fuel aboard each plane, the fighters lumbered down nearly the full 2,000 feet of the Kukum runway before being able to lift off. Admiral Mitscher stood at the end of the runway watching each plane depart. One fighter had a tire blow out during take-off and had to abort. Once the remaining P-38s were airborne, another airplane had trouble drawing fuel from its external tanks and had to turn back. Both pilots who aborted were part of the "hunter" group so two pilots from the cover group were reassigned.

ww2dbaseMajor Mitchell now led sixteen fighters out to sea at low level to avoid Japanese coast watchers and radar. Mitchell relied on his new Navy compass to maintain the group's course according to his very detailed plan. After the last scheduled course change, the group started climbing to their assigned attack altitudes.

ww2dbaseMitchell had led his planes to the intercept point one minute ahead of schedule at 9:34 AM. Within a minute, Lieutenant Douglas Canning, generally considered to have the best eyesight of any pilot in the squadron, broke radio silence announcing, "Bogeys, eleven o'clock high." Mitchell had delivered the fighters to precisely the intended location and at precisely the intended moment. He ordered pilots to drop their tanks and for the hunter group to engage. Lieutenant Besby Holmes of the hunter group was delayed, however, because his tanks did not immediately separate from his plane. Holmes' wingman, Lieutenant Raymond Hine, stayed with him as Holmes made several radical maneuvers to try to shake the tanks loose. Meanwhile, the other two hunter planes piloted by Captain Thomas Lanphier and Lieutenant Rex Barber attacked immediately.

ww2dbaseUpon seeing the attacking Americans, both Japanese bombers dove sharply while the higher flying fighter escort dove in an attempt to drive off the fork-tailed fighters. Lanphier flew straight at the Zeros, guns blazing, and broke up their formation. Barber veered off sharply to avoid colliding head-on with a Zero and in so doing, found himself behind one of the diving Betty bombers. Barber followed the bomber to tree-top level over southern Bougainville and began firing. He was able to "walk" his stream of machine gun bullets across the bomber's right wing and engine, down the fuselage, and across its tail. The right engine began to smoke and the bomber lurched downward toward the trees. Barber's greater speed caused him to close to almost 100 feet, requiring him to snap-roll out and disengage. When he looked back, all he saw was black smoke rising from the jungle.

ww2dbaseMeanwhile, Holmes had finally shed his drop tanks and he was on the tail of the other bomber. This bomber had turned out to sea and was skimming the wave-tops. Holmes fired his guns at the bomber followed by his wingman, Hine, and the bomber's engines began trailing smoke. As Barber rolled out from the pursuit of his bomber, several Zero fighters swooped in behind him. Barber's plane was hit several times but remained flyable and maneuverable. After some evasive actions, he found himself closing on the bomber that Holmes and Hine had been chasing. Barber's guns scored some more hits before the bomber plunged into the sea. Holmes and Hine then drove the Zeros off of Barber's tail. The engagement was over.

ww2dbaseThe American intelligence had led Mitchell to believe the Japanese formation would have only one Betty bomber but they encountered two. Had Mitchell known this, he would have doubled the size of the "hunter" group. But once the engagement was over with all Japanese bombers shot down and the Zeros scattered, the American P-38s regrouped and departed on a direct course for Guadalcanal. As they regrouped, Hine did not join them. His airplane had been last seen heading out to sea with one engine smoking. No one knew what happened to him but a tangle with the Zeros seemed likely. Hine was not seen again.

ww2dbaseAftermath

ww2dbaseMajor Mitchell's plan for a quick getaway back down the "Slot" immediately after the engagement was primarily out of fuel concerns. It was also known the Japanese had many fighters based at Buin on Bougainville and Mitchell had expected those Zeros would scramble to intercept his planes. These Zeros did not launch but another consequence of the planned getaway was that there was no time to search for Hine or to loiter over him if they were to find him.

ww2dbaseThe direct return flight brought fourteen of the fifteen remaining fighters back to Kukum Field safely. Holmes was so low on fuel that he had to land on an advance airstrip in the Russell Islands. So precise had the fuel calculations been that as one fighter was taxiing off the Kukum runway, its engines sputtered to a stop due to fuel exhaustion. Captain Lanphier, however, had enough fuel that upon his arrival he buzzed Kukum field with a victory roll. More significantly, he broke radio silence with an air-to-ground message in plain English that was an unmistakable reference to having shot down Yamamoto. This was directly contrary to orders on a couple of levels, breaking radio silence generally and identifying Yamamoto in particular.

ww2dbaseRex Barber had been flying the Lightning normally flown by another pilot. When Barber returned the borrowed airplane to base, the ground crews counted and patched 104 bullet holes. Owing to Barber's custom of flying very close to his targets, he also returned the fighter with a prominent dent in the underside from aircraft parts flying off the second bomber as he was shooting at it.

ww2dbaseThe Americans assumed there had been no survivors aboard either Japanese bomber, but that turned out to be incorrect. There were no survivors in the airplane that crashed into the jungle but three people survived in the bomber that crashed into the sea. Chief of Staff Matome Ugaki survived the water landing but Admiral Yamamoto's body lay in the jungle with the wreckage of his airplane. Japanese forces did not reach the jungle crash site until the following day where they found Yamamoto's white gloved hand still clutching his sword. He had been killed by one (perhaps two) of Barber's .50 caliber bullets and not from the crash. The Japanese did not release word of Yamamoto's death, even to their own public, until 21 May 1943. It was not until this release that the Americans had absolute confirmation of the mission's results. Yamamoto's ashes were returned to Japan with great pageantry and he was given an elaborate state funeral. A portion of his ashes were buried in the Tama Cemetery in Tokyo and a portion buried at his ancestral home in Nagaoka. Yamamoto was posthumously promoted to Marshal Admiral of the Imperial Japanese Navy and was awarded Japan's highest honor, the Supreme Order of the Chrysanthemum.

ww2dbaseWhen the original radio message was intercepted by the Americans, it was also intercepted by the British and similarly decoded and translated. And, just as the news went straight to the top of the American hierarchy, it also went straight to British Prime Minister Winston Churchill. Churchill thought the correct course of action was obvious, do nothing. He thought that acting on the intelligence would explode the secret of the codebreaking. Churchill felt this would likely not only cause the Japanese to change their own code but also prompt them to urge their allies, the Germans, to change their code as well. This would have been disastrous for the war the British were fighting in Europe. Churchill sent messages to Roosevelt urging him to take no action on the Yamamoto intelligence but it is unclear whether Roosevelt saw the messages before the events unfolded. When Churchill was told that the Americans had not only acted on the intelligence but had shot down Yamamoto, he was furious. All sharing of British intelligence with the Americans ceased immediately and remained blacked out for several weeks.

ww2dbaseChurchill's worst fears were nearly realized, too. After the mission, Barber and Lanphier were granted ten days' leave in New Zealand. While on a golf course with chief of the Solomon fighter command Brigadier General Dean Strother, they were approached by Associated Press war correspondent J. Norman Lodge. Lodge had already heard much about the Yamamoto mission and asked the pilots to just help him with a few details. Foolishly, Lanphier and Barber talked quite freely about the mission, as did Strother. Strother finished by advising Lodge to forget about the story since it would undoubtedly never clear the censors. Nevertheless, on 11 May 1943, days before the Japanese released word of Yamamoto's death, Lodge filed his story and it was a bombshell. Although he did not mention the codebreaking successes, he did include several details that were troubling to the censors. He wrote that American intelligence had been tracking Yamamoto for days before the mission, that the pilots knew specifically they were going after Yamamoto, he included details of the attack that echoed Lanphier's account, and he quoted Strother as saying they had known Yamamoto's itinerary. Lodge's story was blocked by the censors and sent straight up to Halsey who called for Barber, Lanphier, and Strother to immediately return to his headquarters. Barber described what happened next as "a tirade of profanity the like of which I had never heard before. He accused us of everything he could think of from being traitors to our country to being so stupid that we had no right to wear the American uniform. That we should be court-martialed, reduced to privates, and jailed for talking to Lodge." Mitscher had recommended Barber, Lanphier, Mitchell, Holmes, and Hine (posthumously) for the Medal of Honor. Halsey downgraded the recommendation to the Navy Cross across the board, apparently because of these security blunders (the incident apparently did not hamper Strother's prospects, however, as he eventually rose to four-star general in the Air Force in charge of NORAD).

ww2dbaseOn a strategic level, the removal of Yamamoto from the Japanese leadership largely had the effect the Americans had hoped for. Japanese morale, both civilian and military, was shattered. Admiral Mineichi Koga was selected as the new Commander in Chief of the Combined Fleet. Koga was an able commander but unimaginative compared to Yamamoto. Whether the result of this leadership change or other fortunes of war, the Japanese did not win another significant naval battle after this point.

ww2dbaseDebate

ww2dbaseThe Yamamoto mission has been debated on several levels ever since it happened. The topics of debate generally fall into two categories: Was it appropriate to have targeted Yamamoto in the first place? and; What really happened in the air over Bougainville?

ww2dbaseThe earliest conversation around the propriety of the mission itself repeats Churchill's concern about risking the secret that the Japanese and German codes had been broken. This was a hot topic for the rest of the war but has been cooling down ever since, largely because of the way things turned out. The other conversation surrounding the decision to intercept Yamamoto questions whether it was proper to deliberately target a specific foreign military leader. This question was raised at the time, before the mission was authorized, and was quickly settled that a leader in Yamamoto's position was without much doubt a legitimate military target. On an ethical level, the Yamamoto mission was little different from what snipers had been doing in all armies for a long time. Since World War II as the rules of war have come into a much sharper focus, the Yamamoto case has been looked at in retrospect with a different layer of scrutiny. A leader such as Yamamoto would generally still be considered a legal and legitimate target during wartime but with a more extensive body of legal authority behind it. As recently as 2020, when a United States drone strike killed Iranian Major General Qasem Soleimani, the Yamamoto case was cited as a precedent in support of that mission.

ww2dbaseThe question of advisability also comes up from those who speculate that Yamamoto's stature in Japan and his knowledge of the United States put him in a unique position to have exerted some influence as a moderate in the War Cabinet, perhaps persuading a negotiated peace that might have shortened the war. This remains highly conjectural and would have also required several other planets to align.

ww2dbaseThe debate over what happened in the air is more complicated and has a different tone. Captain Lanphier, the leader of the four-plane "hunter" group, claimed from the start that he had shot down the bomber carrying Yamamoto. This would have been mildly puzzling at the time since no one among the Americans knew which bomber carried Yamamoto until the Japanese released the news a month later. But Lanphier claimed to have taken a shot at a bomber from nearly 90-degrees off the bomber's right resulting in the bomber losing a wing before the bomber crashed into the jungle. He also claimed to have shot down at least one Zero fighter. Lieutenant Barber claimed he shot at one bomber from behind that also crashed in the jungle. Lieutenants Holmes and Barber claimed to have each taken shots at another bomber that crashed into the sea. Initially, credit was given for destroying three bombers and three fighters, but there was still no assessment of which bomber carried Yamamoto. Largely because of Lanphier's consistent and forceful claims to have shot down Yamamoto, he was generally acknowledged to have done it for a long time, even though the Army split the credit early on with half-credit going to Lanphier and half-credit to Barber. Barber also got a half-credit for the second bomber that crashed into the sea. The disagreement between Lanphier and Barber over credit lasted for years and resulted in two official Air Force reviews, one pleading in the United States Court of Appeals, and finally one unofficial independent investigation that, for most observers, effectively settled the matter.

ww2dbaseJapanese sources confirmed that there had only been two bombers and that both were lost, one in the Bougainville jungle and the other in the sea. No Zeros were lost but one landed with heavy damage. Yamamoto's body was recovered from the crash site in the jungle. Yamamoto's bomber had its right wing torn off by the crash and did not separate while in flight, as Lanphier had reported. All bullet holes in the bomber had come from the rear, including those that went through Yamamoto's body. The only Japanese pilot from this engagement to survive the war was Warrant Officer Kenji Yanagiya who was not thoroughly interviewed about these events until the mid-1970s. As the pilot of one of the escorting Zeros, he said he watched as Yamamoto's airplane was shot down by a fighter attacking from directly behind. All of this fully supported Barber's claims and discounted Lanphier's.

ww2dbaseWhile opinions still differ among experts to this day, a reasonable assessment is that Lieutenant Rex Barber, alone, shot down Yamamoto's plane that crashed in the jungle of Bougainville; Lieutenants Besby Holmes and Raymond Hine inflicted the fatal damage to Ugaki's bomber that crashed into the sea (with Barber perhaps adding more damage just before the crash); and Captain Thomas Lanphier, after effectively diverting the Zero fighters from the other Lightning fighters, inflicted the damage to the Zero that limped back to the airfield on Bougainville.

ww2dbaseOperation Vengeance

ww2dbaseThe mission to shoot down Yamamoto's airplane has often been referred to as Operation Vengeance but this name was never applied to the mission during the war; no name was applied to this mission during the war. According to the United States Air Force historical archives, there has never been an operation named Vengeance. The name seems to have first appeared in John Deane Potter's 1965 book Yamamoto. No pre-1965 references to Operation Vengeance could be found. It would seem the name derives from a sense of avenging the Pearl Harbor Attack, which was something very much on the minds of everyone involved in planning and executing this mission, whether they called it by this name or not.

ww2dbaseDates and Times

ww2dbaseIt may be important to take note of the inconsistencies in dates and times listed here as compared to other sources. Two different factors must be considered to make sense of this.

ww2dbaseAs to the dates, the International Date Line makes for events in the Solomon Islands versus the Hawaiian Islands being recorded on different dates even though they occurred at the same time. For consistency's sake, all dates used here, unless otherwise noted, conform to the dates used in Rabaul and the Solomon Islands. Thus, when the Japanese radio message was intercepted in Hawaii on 14 Apr 1943, it was actually broadcast from Rabaul on 15 Apr 1943, three days before the flight described in the message.

ww2dbaseAs to the times, the Japanese military used Tokyo time for all times listed in logs and written orders no matter where on the planet the events were taking place. Thus, when Japanese records indicate Yamamoto's airplane took off from Rabaul at 6:10 AM, that corresponds to 8:10 AM local Solomon time since the Solomon Islands are two hours east of the Tokyo time zone. Again for consistency's sake, all times are reported here according to the local Solomon time.

Operation Vengeance Interactive Map

Photographs

Operation Vengeance Timeline