Operation Vengeance

Operation Vengeance was the name given by the Americans to the military operation to kill Japanese Admiral Isoroku Yamamoto on April 18, 1943, during the Solomon Islands campaign in the Pacific Theater of World War II and exactly one year following the United States' most direct previous blow to Japan with the Doolittle Raid. Isoroku Yamamoto, commander of the Combined Fleet of the Imperial Japanese Navy, was killed on Bougainville Island when his transport bomber aircraft was shot down by U.S. Army fighter aircraft operating from Kukum Field on Guadalcanal.

The mission of the U.S. aircraft was specifically to kill Yamamoto and was based on United States Navy intelligence on Yamamoto's itinerary in the Solomon Islands area. The death of Yamamoto reportedly damaged the morale of Japanese naval personnel (described by Samuel Eliot Morison as being considered the equivalent of a major defeat in battle), raised the morale of the Allied forces, and was intended as revenge by U.S. leaders who blamed Yamamoto for the Pearl Harbor attack which initiated the formal state of war between Imperial Japan and the U.S.

After the war, acrimonious debate erupted over which of the U.S fighter pilots involved in the raid deserved the official credit for downing Yamamoto; in a manner similar to other internationally famous combatants killed in war (such as Manfred von Richthofen and Michael Wittmann), the debate persisted for years due to conflicting first-hand reports from the participants, and has never been entirely resolved.

Background
Admiral Isoroku Yamamoto, commander of the Imperial Japanese Navy, scheduled an inspection tour of the Solomon Islands and New Guinea. He planned to inspect Japanese air units participating in the I-Go operation that had begun April 7, 1943, and to boost Japanese morale following the disastrous evacuation of Guadalcanal. On April 14, the U.S. naval intelligence effort code-named "Magic" intercepted and decrypted orders alerting affected Japanese units of the tour.

The original message, NTF131755, addressed to the commanders of Base Unit No. 1, the 11th Air Flotilla, and the 26th Air Flotilla, was encoded in the Japanese Naval Cipher JN-25D (Naval Operations Code Book of the third version of RO), and was picked up by three stations of the "Magic" apparatus, including Fleet Radio Unit Pacific Fleet. The message was then deciphered by Navy cryptographers (among them future Supreme Court Justice John Paul Stevens ); it contained time and location details of Yamamoto's itinerary, as well as the number and types of planes that would transport and accompany him on the journey.

Yamamoto, the decryption revealed, would be flying from Rabaul to Balalae Airfield, on an island near Bougainville in the Solomon Islands, on April 18. He and his staff would be flying in two medium bombers (Mitsubishi G4M Bettys of the 205th Kokutai Naval Air Unit), escorted by six navy fighters (Mitsubishi A6M Zero fighters of the 204th Kokutai NAU), to depart Rabaul at 06:00 and arrive at Ballale at 08:00, Tokyo time.

President Franklin D. Roosevelt ordered Secretary of the Navy Frank Knox to "get Yamamoto." Knox instructed Admiral Chester W. Nimitz of Roosevelt's wishes. Nimitz first consulted Admiral William F. Halsey, Jr., Commander, South Pacific, and then authorized the mission on April 17.

Interception
To avoid detection by radar and Japanese personnel stationed in the Solomon Islands along a straight-line distance of about 400 mi between U.S. forces and Bougainville, the mission entailed an over-water flight south and west of the Solomons. This roundabout approach flight was plotted and measured to be about 600 mi. The fighters would therefore travel 600 miles out to the target and 400 miles back. The 1,000-mile flight, with extra fuel allotted for combat, was beyond the range of the F4F Wildcat and F4U Corsair fighters then available to Navy and Marine squadrons based on Guadalcanal. The mission was instead assigned to the 339th Fighter Squadron, 347th Fighter Group, whose P-38G aircraft, equipped with drop tanks, had the range to intercept and engage.

In preparation for the mission, Marine Corps Lt. Col. Luther S. Moore had the P-38s fitted with a Navy ship's compass to aid in navigation at the request of Major John W. Mitchell, commanding the 339th. The fighters each mounted a standard armament of a 20 mm cannon and four 50-caliber (12.7 mm) machine guns, and were equipped to carry two 165 gal drop tanks under their wings. A limited supply of 330 gal tanks was flown up from New Guinea, sufficient to provide each Lightning with one large tank to replace one of the small tanks. Despite the difference in size, the tanks were located close enough to the aircraft's center of gravity to avoid any performance problems.

Eighteen P-38s were tasked for the mission. One flight of four was designated as the "killer" flight while the remainder, which included two spares, would climb to 18000 ft to act as "top cover" for the expected reaction by Japanese fighters based at Kahili. A flight plan was prepared by the Command Operations Officer, Marine Major John Condon, but was discarded for one prepared by Mitchell. He calculated an intercept time of 09:35, based on the itinerary, to catch the bombers descending over Bougainville, ten minutes before landing at Balalae. He worked backwards from that time and drew four precisely-calculated legs, with a fifth leg added if Yamamoto did not take the most direct route. In addition to heading out over the Coral Sea, the 339th would "wave-hop" all the way to Bougainville at altitudes no greater than 50 feet (15 m), maintaining radio silence en route.

Although the 339th Fighter Squadron officially carried out the mission, ten of the eighteen pilots were drawn from the other two squadrons of the 347th Group. The Commander AirSols, Rear Admiral Marc A. Mitscher, selected four pilots to be designated as the "killer" flight:
 * Capt. Thomas G. Lanphier, Jr.
 * Lt. Rex T. Barber
 * Lt. Besby F. Holmes
 * Lt. Raymond K. Hine

The remaining pilots would act as reserves and provide air cover against any retaliatory attacks by local Japanese fighters:


 * Maj. John Mitchell
 * Lt. William Smith
 * Lt. Gordon Whittiker
 * Lt. Roger Ames


 * Capt. Louis Kittel
 * Lt. Lawrence Graebner
 * Lt. Doug Canning
 * Lt. Delton Goerke


 * Lt. Julius Jacobson
 * Lt. Eldon Stratton
 * Lt. Albert Long
 * Lt. Everett Anglin

A thorough, detailed briefing included a cover story for the source of the intelligence stating that a coastwatcher had spotted an important high-ranking officer boarding an aircraft at Rabaul, but the pilots were not specifically briefed that their target was Admiral Yamamoto. The specially-fitted P-38s took off from Kukum Field on Guadalcanal beginning at 07:25. The date, April 18, was the first anniversary of the Doolittle Raid. Two of the Lightnings assigned to the killer flight dropped out of the mission at the start, one with a tire flattened during takeoff (McLanahan) and the second when its drop tanks would not feed fuel to the engines (Moore).

In Rabaul, despite urgings by local commanders to cancel the trip for fear of ambush, Yamamoto's airplanes took off as scheduled for the trip of 315 mi. They climbed to 6500 ft, with their fighter escort at their 4 o'clock position and 1500 ft higher, split into two V-formations of three planes.

Mitchell's flight of four led the squadron at low altitude, with the killer flight, now consisting of Lanphier, Barber, and spares 1st Lt. Besby F. Holmes and 1st Lt. Raymond K. Hine, immediately behind. Mitchell, fighting off drowsiness, navigated by flight plan and dead reckoning. This proved to be the longest fighter-intercept mission of the war and was so skillfully executed by Mitchell that his force arrived at the intercept point one minute early, at 09:34, just as Yamamoto's aircraft descended into view in a light haze. The P-38s jettisoned the auxiliary tanks, turned to the right to parallel the bombers, and began a full power climb to intercept them.

The tanks on Holmes's P-38 did not detach and his element turned back toward the sea. Mitchell radioed Lanphier and Barber to engage, and they climbed toward the eight aircraft. The nearest escort fighters dropped their own tanks and dived toward the pair of P-38s. Lanphier, in a sound tactical move, immediately turned head-on and climbed towards the escorts while Barber chased the diving bomber transports. Barber banked steeply to turn in behind the bombers and momentarily lost sight of them, but when he regained contact, he was immediately behind one and began firing into its right engine, rear fuselage, and empennage. When Barber hit its left engine, the bomber began to trail heavy black smoke. The Betty rolled violently to the left and Barber narrowly avoided a mid-air collision. Looking back, he saw a column of black smoke and assumed the Betty had crashed into the jungle. Barber headed towards the coast at treetop level, searching for the second bomber, not knowing which one carried the targeted high-ranking officer.

Barber spotted the second bomber, carrying Chief of Staff Vice Admiral Matome Ugaki and part of Yamamoto's staff, low over the water off Moila Point, trying to evade an attack by Holmes, whose wing tanks had finally come off. Holmes damaged the right engine of the Betty, which emitted a white vapor trail, but his closure speed carried him and his wingman Hine past the damaged bomber. Barber attacked the crippled bomber and his bullet strikes caused it to shed metal debris that damaged his own aircraft. The bomber descended and crash-landed in the water. Ugaki and two others survived the crash and were later rescued. Barber, Holmes and Hine were attacked by Zeros, Barber's P-38 receiving 140 hits. Holmes and Barber each claimed a Zero shot down during this melee, although Japanese records show that no Zeros were lost. The top cover briefly engaged reacting Zeros without making any kills. Mitchell observed the column of smoke from Yamamoto's crashed bomber. Hine's P-38 had disappeared by this point, presumably crashed into the water. Running close to minimum fuel levels for return to base, the P-38s broke off contact, with Holmes so short of fuel that he was forced to land in the Russell Islands. Hine was the only pilot who did not return.

As he approached Henderson Field, Lanphier radioed the fighter director on Guadalcanal that "That son of a bitch will not be dictating any peace terms in the White House", breaching security. Immediately on landing (his plane was so short on fuel that one engine quit during landing rollout) he put in a claim for shooting down Yamamoto.

Aftermath
The crash site and body of Admiral Yamamoto were found the next day in the jungle north of the coastal site of the former Australian patrol post and Catholic mission of Buin (which was re-established, after the war, several kilometres inland) by a Japanese search and rescue party, led by Army engineer Lieutenant Hamasuna. According to Hamasuna, Yamamoto had been thrown clear of the plane's wreckage, his white-gloved hand grasping the hilt of his katana, still upright in his seat under a tree. Hamasuna said Yamamoto was instantly recognizable, head dipped down as if deep in thought. A post-mortem of the body disclosed that Yamamoto received two wounds, one to the back of his left shoulder and one to his left lower jaw that exited above his right eye. The Japanese navy doctor examining the body determined that the head wound killed Yamamoto. The more violent details of Yamamoto's death were hidden from the Japanese public; the medical report was whitewashed, changed "on orders from above", according to biographer Hiroyuki Agawa.

In Japan this became known as the "Navy kō incident"(ja:海軍甲事件). It raised morale in the United States and shocked the Japanese, who were officially told about the incident only on May 21, 1943. To cover up the fact that the Allies were reading Japanese code, American news agencies were given the same cover story used to brief the 339th Fighter Squadron, that civilian coastwatchers in the Solomons observed Yamamoto boarding a bomber and relayed the information by radio to American naval forces in the immediate area.

The tail number of Yamamoto's aircraft was T1-323. The wreckage and crash site are now tourist attractions near Buin, Bougainville Island. The left wing of this aircraft was subsequently removed intact and taken to the Isoroku Yamamoto Family Museum in Nagaoka, Japan.

Who shot down Yamamoto?
Although Operation Vengeance was one of the most expertly-executed missions in American air force history, the whole episode has subsequently been overshadowed by controversy over who actually shot down the admiral's aircraft. The issue began immediately after the mission when the US military quickly credited Thomas Lanphier with the kill. The captain claimed in his report back at Guadalcanal that after turning to engage the escort Zeroes and shooting the wings off one, he had flipped upside down as he circled back towards the two bombers. On seeing the lead bomber turning in a circle below him, he came out of his turn at a right angle to the circling bomber and fired blowing off its right wing. The plane then crashed into the jungle. Lanphier also reported that he witnessed Lt. Rex Barber shoot down another bomber which also crashed into the jungle.

From the report, US intelligence assumed that three bombers had been downed because Lt. Besby F. Holmes claimed the "Betty" that crashed into the sea. None of the remaining pilots were debriefed after the mission because no formal interrogation procedures existed on Guadalcanal at that time. Likewise Lanphier's claim of the kill was never officially witnessed. Many of the other mission's pilots soon became skeptical with the official US Air Forces' version.

Six months later unauthorized details about the operation leaked into the press. In October 1943 an issue of Time Magazine featured an article about Vengeance and mentioned Lanphier by name. An outraged US Navy considered it a serious breach of security. As a result, Maj. John Mitchell, who had been nominated for the Medal of Honor, was downgraded to the Navy Cross; this was the same award subsequently presented to all the pilots of the killer flight.



The controversy did little to subside after the war because of the testimony of the surviving Japanese escort pilot who witnessed the mission. Zero pilot Kenji Yanagiya, who had been in Yamamoto's fighter escort, told John Mitchell he might have been responsible for the loss of Lt. Raymond Hine because he had heavily damaged a P-38 (escorting another Lightning that had not dropped its fuel tanks), although neither he nor any of the other Zero pilots had claimed a P-38 that day. The cause of Hine's disappearance is still officially undetermined. Yanagiya also claimed none of the escorting Japanese fighters were shot down, only one was damaged enough that it required a day of repair at Buin. These details contradicted Lanphier's claim for a Zero. Likewise Japanese military records confirmed that only two Mitsubishi G4M bombers had been shot down on the day. Eventually Lanphier and Barber were officially awarded half credits for the destruction of the bomber that crashed into the jungle, and half credits to Barber and Holmes for the bomber that crashed at sea. Several ground inspections of Yamamoto's crash site have determined that the path of the bullet impacts validated Barber's account because "all visible gunfire and shrapnel damage was caused by bullets entering from immediately behind the bomber" not from the right.

Subsequently Barber petitioned the Air Force Board for Correction of Military Records to have his half credit on the bomber shared with Lanphier changed to a whole credit. In September 1991 The Air Force History Office advised the board that "enough uncertainty" existed in both Lanphier’s and Barber’s claims for them both to be accepted; the board's decision was split on Barber’s petition. Secretary of the Air Force Donald B. Rice ruled to retain the shared credit. Barber then applied to the U.S. 9th Circuit Court of Appeals to have the ruling of the Secretary of the Air Force overturned and the opposing claims re-investigated, but the court refused to intervene.

In May 2006, Air Force Magazine published a letter by Doug Canning, a former pilot of the 347th Fighter Group who flew on Operation Vengeance (he escorted Lieutenant Holmes back to Russell Island). Canning, who was friends with both Lanphier and Barber, stated that Lanphier had written the official report, medal citations, and several magazine articles about the mission. He also claimed Barber had been willing to share the half credit for shooting down Yamamoto until Lanphier had given him an unpublished manuscript he had written claiming he alone had shot down the admiral. Canning agreed that Barber had a strong case for his claim citing the testimony of another pilot from Yamamoto's Zero escort, Kenji Yanagiya, who saw Yamamoto's "Betty" crash 20 to 30 seconds after being hit from behind by fire from a P-38. Likewise the second Betty carrying Admiral Ugaki crashed 20 seconds after being struck by aircraft fire. Canning stated categorically that the P-38Gs flown that day did not have aileron boost to assist in turning (as did later models) making it physically impossible for Lanphier's aircraft to have made the 180 degree turn he claimed in order to shoot down Yamamoto's plane.