Operation Vengeance

Death of Isoroku Yamamoto
Part of the Pacific Theater of World War II
Japanese Admiral Isoroku Yamamoto
Date April 18, 1943 Location Bougainville in the South Pacific Result Allied victory
Belligerents
United States	Empire of Japan
Commanders and leaders
William F. Halsey, Jr. John W. Mitchell	Isoroku Yamamoto†
Strength
16 fighter aircraft	2 bombers, 6 fighter aircraft
Casualties and losses
1 P-38G destroyed, 1 pilot killed	2 bombers destroyed, 19 killed

The Death of Isoroku Yamamoto occurred on April 18, 1943 during the Solomon Islands campaign in the Pacific Theater of World War II. Japanese admiral 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 fighter aircraft of the United States of America (U.S.) operating from Henderson Field on Guadalcanal.

The mission of the U.S. aircraft was specifically to kill Yamamoto, and was based on U.S. Navy intelligence on Yamamoto's travel plans 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), aided the morale of members of the Allied forces, and, controversially, been intended as an act of revenge by U.S. President Franklin D. Roosevelt who blamed Yamamoto for the Pearl Harbor attack which initiated the formal state of war between Japan and the U.S.

Background

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, Admiral Isoroku Yamamoto, commander of the Imperial Japanese Navy, decided to make an inspection tour of the Solomons and New Guinea. On April 14, the US 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 contained specific details regarding Yamamoto's arrival and departure times and locations, as well as the number and types of planes that would transport and accompany him on the journey.

Map of southwest Pacific area where the mission took place. Yamamoto flew from Rabaul on New Britain (upper left) to Bougainville (center) where his aircraft was attacked by U.S. fighters from Guadalcanal (lower right)

Yamamoto, the itinerary revealed, would be flying from Rabaul to Ballale 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 fighters Mitsubishi A6M Zeros of the 204th Kokutai NAU), to depart Rabaul at 0600 and arrive at Ballale at 0800, Tokyo time.

Secretary of the Navy Frank Knox instructed by President Roosevelt to communicate his wishes, "Get Yamamoto" to Admiral Chester W. Nimitz consulted Adm. William F. Halsey, Jr., Commander, South Pacific, then authorized the mission on April 17.

Interception mission

To avoid detection by radar and Japanese coast-watchers, the mission entailed an over-water flight south of the Solomons, a distance of 430 miles. This was beyond the range of the F4F Wildcat and F4U Corsair fighters then available to Navy and Marine squadrons of Guadalcanal's Cactus Air Force. The mission was then given to the 339th Fighter Squadron of the 347th Fighter Group, Thirteenth Air Force, whose P-38G aircraft, equipped with drop tanks, would have the range to intercept and engage.

Planning for this mission was begun by Fighter Command's deputy, Marine Lt. Col. Luther S. Moore, who had the P-38s fitted with a navy ship's compass at the request of Major John W. Mitchell, commanding officer of the 339th, to aid in navigation. These fighters each carried a 20 mm cannon and 4 × 50-calibre (12.7 mm) machine guns and normally carried two 165-gallon (625 L) drop tanks under their wings. For this raid a limited supply of 310-gallon (1136 L) tanks were flown up from New Guinea, sufficient to provide each Lightning with one of the larger tanks. Despite the differences in size, the tanks were located close enough to the aircraft's center of gravity to negate any performance problems.

P-38G Lightning

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 18,000 feet 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 0935, based on the itinerary, to catch the bombers descending over Bougainville, ten minutes before landing at Ballale airfield. He worked backwards from that time and drew four precisely-calculated legs, with a fifth leg added if Yamamoto took other than the directmost 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 flew the mission, ten of the eighteen pilots were drawn from the other two squadrons of the 347th Group. A thorough, detailed briefing included a cover story for the source of the intelligence stating that a coast-watcher had spotted an important high 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 Guadalcanal's Fighter Two airstrip beginning at 0725. The date, April 18, had the significance of being the one-year anniversary of the Doolittle Raid as well as being Easter Sunday. Two of the Lightnings assigned to the killer flight dropped out of the mission at the start, one with a tire flattened during takeoff, and the second when its drop tanks would not feed fuel to the engines.

In Rabaul, despite urgings by local commanders to cancel the trip for fear of ambush, Yamamoto's planes took off as scheduled for the 315-mile trip. They climbed to 6,500 feet, with their fighter escort behind and 1,500 feet higher, split into two V-formations of three planes.

File:G4MBetty.jpg

"Betty" bomber similar to the one carrying Yamamoto

Mitchell's flight of four led the squadron "on the deck" with the killer flight, consisting of Capt. Thomas G. Lanphier, Jr., 1st Lt. Rex T. Barber, and the spares, Lt. Besby F. Holmes and Lt. Raymond K. Hine, immediately behind, fighting off drowsiness, navigating by flight plan and dead reckoning. This proved to be the longest fighter-intercept mission of the war, and was so skillfully executed by Major Mitchell that his force arrived at the intercept point one minute early, at 0934, just as the ever-punctual Yamamoto's aircraft descended into view in a light haze. Mitchell ordered his planes to drop tanks, turned to the right to parallel the bombers, and began a full power climb.

Lt. Holmes was unable to drop his tanks and turned back to sea, followed by his wingman, Lt. Hine. Mitchell radioed Lanphier and Barber to engage and they turned to climb toward the eight aircraft. The closest escort fighters dropped their own tanks and began to dive 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. Barber hit its left engine, it began to trail heavy black smoke, and the Betty rolled violently to the left, Barber narrowly avoiding a collision. Looking back he saw a column of black smoke and assumed it had crashed into the jungle. Barber headed towards the coast at treetop level, searching for the second bomber, not knowing which bomber carried Yamamoto.

Barber spotted the second bomber low over the water off Moila Point just as Holmes (whose wing tanks had finally come off) and Hine attacked it. Holmes damaged the right engine of the Betty, which began emitting a white vapor trail, then he and Hine flew over the damaged bomber, carrying Chief of Staff Vice Admiral Matome Ugaki and part of Yamamoto's staff. Barber next attacked the stricken bomber, pieces of it damaging his own aircraft, and it crash-landed in the water. Ugaki survived the crash as did two others and all were later rescued. Barber, Holmes and Hine were attacked by Zeroes, Barber's P-38 receiving 140 hits, and Holmes and Barber each claimed a Zero shot down during this meleé. The top cover briefly engaged reacting Zeroes without making any kills and Major Mitchell observed the column of smoke from Yamamoto's crashed bomber. The P-38s broke off contact and returned to base, with Lt. Holmes so short of fuel that he was forced to land in the Russell Islands. Lt. Hine's Lightning was the only one missing and was never found. He is listed on the Tablets of the Missing at Manila American Cemetery along with awards: Navy Cross; Distinguished Flying Cross; Air Medal; Purple Heart.

Aftermath

As he approached Henderson Field, Lanphier radioed the Guadalcanal fighter director that "I got Yamamoto", breaching security on the mission. Immediately on landing (his plane was so short on fuel that one engine quit during landing rollout) he again put in a claim for shooting down the bomber, relating that when he turned to engage the escort Zeroes he shot the wing off one, flipped upside down as he circled back towards the bombers, and saw the lead bomber turning a circle below him. He stated he came out of his turn at a right angle to the circling bomber and fired, blowing off its right wing. He stated that he witnessed Barber shoot down another bomber which also crashed in the jungle. Holmes put in a claim for the Betty that crashed into the water, so it was assumed that three bombers had been downed. The fifteen surviving pilots were not "debriefed" after the mission because this formal interrogation did not exist in the procedures on Guadalcanal at that time, and thus it was never formally established that no one else witnessed Lanphier's claim.

The crash site and body of Admiral Yamamoto were found the next day in the jungle north of the then-coastal site of the former Australian patrol post and Catholic mission of Buin (after the war re-established 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. Whether or not the admiral initially survived the crash has also been a matter of controversy in Japan.

In Japan this became known as the "Navy kō incident"(海軍甲事件). It raised morale in the States, and shocked the Japanese who were officially told about the incident only on 21 May 1943. To cover up the fact that the Allies were reading Japanese code, American news agencies were told the cover story originally created for briefing the 339th, that civilian coast-watchers in the Solomons saw Yamamoto boarding a bomber in the area.

Controversy

File:Barber cross.jpg

Rex Barber is awarded the Navy Cross for his actions during the mission that killed Yamamoto.

Lanphier initially received credit for the kill of Yamamoto's bomber but the other pilots on the mission were immediately skeptical. Although one of the most expertly-executed missions in history, the interception was subsequently marred by controversy over who actually shot down Yamamoto, and by Navy outrage over unauthorized releases of operational details to the press, including an October 1943 issue of Time Magazine which featured articles on both the shootdown and Lanphier by name. Mitchell had been nominated for the Medal of Honor for the mission, but as a result of the security issues this was downgraded to the Navy Cross, which he and all the pilots of the killer flight were subsequently awarded.

After the war it was found that none of the escorting Japanese fighters were even damaged, much less shot down, and Lanphier was stripped of his claim for a Zero shot down. Since other Zero fighters were taking off from nearby Kahili airfield, both Barber and Holmes were allowed their claims during the second combat. Also records confirmed that only two bombers had been shot down, not three, and subsequently the Air Force officially awarded "half kills" to Lanphier and Barber for the Yamamoto shootdown. A video-taped interview in 1985 with one of the escorting Zero pilots, Kenji Yanagiya, appeared to corroborate Barber's claim, but the Air Force declined to reopen the issue.

Rex Barber then sued in Federal Court 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 the May, 2006 issue of AIR FORCE Magazine, Douglas S. Canning, a former member of the 347th Fighter Group who flew the Yamamoto mission (Canning escorted Lt. Holmes back to the Russells) and was friends with both Lanphier and Barber, published a letter in which he stated that Lanphier, in addition to writing the official report, medal citations, and several magazine articles, had also written a detailed manuscript, never published, claiming he alone shot down Yamamoto. Until reading that manuscript, Barber had been willing to share half credit for the kill. Canning cites the testimony of the Japanese Zero pilot, Yanagiya, that Yamamoto's Betty crashed 20 to 30 seconds after being hit by fire from a P-38, and from Admiral Ugaki on the second Betty that Yamamoto's plane crashed 20 seconds after being struck. Canning stated categorically that the P-38Gs flown that day did not have aileron boost to assist in turning (as did later models) and that it was physically impossible for Lanphier's aircraft to have made the 180 degree turn he claimed in order to shoot down Yamamoto.

Recent examination of the crash site and damage to the Betty confirms the claim of Barber and disproves the account from Lanphier, hence feeling among historians that Barber alone deserves credit.

References

Books

• Davis, Burke (1969). Get Yamamoto. New York: Random House. ASIN B0006BZ2OC. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help)
• Davis, Donald A. (2005). Lightning Strike : The Secret Mission to Kill Admiral Yamamoto and Avenge Pearl Harbor. New York: St. Martin's Press. ISBN 0-312-30906-6. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help)-Uses Burke Davis' and Glines' books as well as new research. Online views of selections of the book: [1]
• Glines, Carroll V. (1990). Attack on Yamamoto. New York: Crown (1st edition). ISBN 0-517-57728-3. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help)-Documents both the mission to shoot down Yamamoto and the subsequent controversies with thorough research, including personal interviews with all surviving participants and researchers who examined the crash site.
• Hammel, Eric (1992 (2000 reissue)). Aces Against Japan: The American Aces Speak. Pacifica Press. ISBN 0-935553-43-6. {{cite book}}: Check date values in: |year= (help); Cite has empty unknown parameter: |coauthors= (help)CS1 maint: year (link)- Contains interview with Besby Frank Holmes.
• Hammel, Eric (1996). Aces Against Japan II: The American Aces Speak. Pacifica Press. ISBN 0-935553-14-2. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help)- Contains another interview with Besby Frank Holmes.

Other media

• Canning, Douglas S. (May, 2006, Volume 89, Number 5, pp 7-8). "Who Shot Down Yamamoto?, letter,". Air Force Magazine. Arlington, VA, USA: Air Force Association. {{cite book}}: Check date values in: |year= (help); Cite has empty unknown parameter: |coauthors= (help)CS1 maint: year (link)
• Grant, Rebecca (March, 2006, Volume 89, Number 3, p. 62). "Magic and Lightning". Air Force Magazine. Arlington, VA, USA: Air Force Association. {{cite book}}: Check date values in: |year= (help); Cite has empty unknown parameter: |coauthors= (help)CS1 maint: year (link)
• Holley, Joe (July 27, 2006, page B7 (Obituaries)). "Besby Frank Holmes; WWII Fighter Pilot". The Washington Post. Washington, DC, USA. {{cite book}}: Check date values in: |year= (help); Cite has empty unknown parameter: |coauthors= (help)CS1 maint: year (link)- Obituary on the death of Lt. Col. Frank Holmes.

Fiction

• In the novel Cryptonomicon, Neal Stephenson wrote a particularly amusing account of the assassination events from Yamamoto's viewpoint.

See also

T1-323- Tail number of Yamamoto's aircraft. The wreckage and crash site are now tourist attractions near Buin, Bougainville. The left wing of this aircraft was subsequently removed intact and then placed in the Isoroku Yamamoto Family Museum located in Nagaoka, Japan (Niigata Prefecture) because of the scavenging of this site.