We Killed Yamamoto: a detailed description of the P-38 assassination of the man behind Pearl Harbor

Yamamoto’s plane was no longer in sight; dominating the horizon was a column of black smoke boiling from the dense jungle into the air.

Admiral Yamamoto was Japan’s mastermind behind Pearl Harbor, and he was a top target in the war that followed. In 1943, US codebreakers cracked the secret of Yamamoto’s flightplan for a forthcoming visit to Rabaul. But for the P-38 Lightning unit that was ordered to find, intercept, and shoot down his aircraft, at extreme range, it was still one of the toughest jobs of World War II.

The following is a detailed description of the interception and is based on Si Sheppard’s book We Killed Yamamoto.

On Apr. 18, 1943 the two Japanese Navy G4M (Betty) bombers carrying Admiral Isoruku Yamamoto (in G4M Betty bomber #1) and Chief of Staff Matome Ugaki (in Betty #2) took off at 0600hrs from Lakunai airfield, on New Britain’s east coast and were joined by six escorting Zero fighters from No. 204 Kaigun Kokutai. As a concession to security, and to permit the Combined Fleet commander to see something of his deployed forces, the flight path made its first landfall at the southern tip of New Ireland, then turned south along the east coast of Bougainville, past the Japanese bases at Buka and Kieta, then on to Buin.

The Zeros formed up in two flights of three, each in a “V” formation. The Japanese kept the mountains of Bougainville to their left on the assumption that if they were to encounter American fighters these would have to come from the seaward side. The bombers maintained an altitude of 6,500ft with the fighters at 8,200ft above and a mile behind on either side of them.

Ugaki’s Betty carried its regular armament of three 13mm guns and one 20mm gun, but because of the weight of the ammunition boxes, the squadron leader ordered only one belt for each weapon. There is no evidence Yamamoto’s Betty was armed at all. At every level, Japanese operational security was incredibly lax. A message was sent after takeoff by the chief pilot of the plane carrying Yamamoto, informing Ballale base that they were “due to arrive 0745.”

Before long, Ugaki, who was sitting in the captain’s seat immediately behind chief pilot Hayashi, nodded off. At 0730 the flight caught its first glimpse of Ballale and began a shallow descent in preparation for landing. Tanimoto, who was in the copilot’s seat, passed the still half-asleep Ugaki a note that read: “Expect to arrive at Ballale 0745.” The formation was flying along the west coast of Bougainville, with dense jungle visible below.

Suddenly, one of the escort fighters accelerated ahead of the second bomber. It dipped its wings, and the pilot could be seen pointing to something. Another of the escort Zeros approached the lead bomber, which promptly increased speed and pushed its nose down in a rapid descent. At the controls of the second bomber was Hiroshi Hayashi, a flight petty officer second class in the Japanese Navy assigned to the 705th Air Squadron, who had served for nearly a year at Rabaul. His immediate response was professional indignation; it was dangerous to drop altitude at such a rate. But his ordeal was just beginning.

In fact, a flight of 16 P-38 Lightning fighters from USAAF 374^th and 18^th Fighter Groups under Major John Mitchell, had spotted the Japanese bombers and was turning to intercept.

It was Doug Canning, flying No. 3 in the flight, who broke radio silence: “Bogeys! Eleven o’clock high!” At that moment, Mitchell spotted two Japanese bombers (not the lone Betty anticipated by the intelligence) crossing the western tip of Bougainville 5 miles away at about 4,500ft in a shallow descent toward Ballale with six Zeros behind them in two flights of three about a thousand feet higher. He replied “Roger,” and “I have ‘em.”

The P-38s were still at wave-top height and heading toward the Japanese aircraft at a 90-degree angle. Mitchell turned right, parallel with their track, and firewalled his engine to climb as fast as he could. He ordered his pilots to “skin off your tanks” and pulled his own belly tank release, watching as Julius Jacobson, Canning, and Delton Goerke dropped theirs.

Besby Holmes’ tanks wouldn’t detach: “I jigged the release, I checked the circuit breakers, nothing happened. I couldn’t drop them.” He radioed his flight leader Thomas Lanphier (who led the section tasked to attack Yamamoto’s bomber), “Wait a minute Tom, I’ll tear my tanks off, just give me a second.” Getting no response from Lanphier, Holmes pulled away from the formation back out over the water, turning seaward and nosing down to pick up speed, hoping the acceleration would help shake the tanks loose, “That was a mistake as far as I was concerned,” Mitchell later noted, while showing due deference to Raymond Hine, Holmes’ wingman, who “rightfully followed him to protect him.”

From that moment, the entire operation seemed to be falling to pieces. Mitchell (whose section was tasked to provide high cover to the other Lightnings) felt his heart sink; his fighters had now to face twice as many bombers as anticipated. Worse, he could not order his pilots to concentrate on one of the Bettys as he had no idea which one Was Yamamoto’s.

With icy resolve Mitchell led his flight in its climb to the predetermined CAP altitude as he radioed to Lanphier: “He’s your meat, Tom.” Lanphier acknowledged, and the two remaining planes of the killer flight turned toward the eight enemy aircraft on a rising intercept course.

The covering flight continued climbing, parallel to the Japanese planes. Mitchell was very tempted to level off and join in the pursuit. “If I had known they weren’t going to send any fighters up to greet the admiral, I would have made the attack. I would have taken over, Lanphier or anyone else be damned. I would have gone in first.” He had opted for the high cover role because he anticipated mixing it up with the Zeros scrambling from Buin. But none of these so much as got off the ground while the interception was in progress — “a big disappointment to me and the rest of the cover flight.”

The action would therefore focus on the killer flight. All subsequent accounts agree that Lanphier (on the left side of the attacking element) made a climbing turn to the left (north by northwest). In so doing, he had gone nose to nose with the three escort Zeros on the seaward side of the formation. Rex Barber (Lanphier’s wingman), again by all subsequent accounts, banked hard right. Mitchell, watching from above radioed, “Get the bombers … damn it all, the bombers!” Neither Barber nor Lanphier would later recall hearing this radio transmission. They were too mission-focused.

At this point, the accounts diverge. Exactly what happened over the next few minutes has been the source of bitter contention for more than three-quarters of a century. The participants all went to their graves each swearing their perspective was the legitimate one, and no version of the story is compatible with any of the others.

From the Japanese point of view, the events of that day were perfectly straightforward. They were ambushed and defeated. The pilots in the escorting Zeros were caught completely by surprise and reacted fatally late to the threat. They were flying above the bombers and scanning the horizon ahead of them to the south; they never suspected American fighters would approach from behind them at a lower altitude. One of their number, Kenji Yanagiya, only realized they were under attack when the flight leader suddenly rocked his wings and went immediately into a full-throttle dive.

The immediate thought that went through his mind was not to try and shoot down the P-38s, but rather to deflect them from their attack path. All six of the Zeros made a straight dive from their higher altitude to position themselves between the bombers and the oncoming P-38s. Rather than firing at the American fighters, they kept shooting in front of the P-38s, trying to prevent them from closing on the Bettys. The enemy was relentless, however: “They were all firing at the bomber and they were just going in rows, so to speak. They were all firing … Shoot, flip, go down — just like that.”

Aboard the bombers, confusion was total. “What happened?” Ugaki called out to his plane’s captain, who replied “It must be some mistake.” The crew onboard took up battle stations, cleared their guns, and prepared for firing. “For a moment, the wind blowing in and the handling of machine guns and all caused one mixed, disturbing noise,” Ugaki recalled. His bomber made a sudden evasive turn of more than 90 degrees. Having spotted the American fighters, the bomber’s captain, “seeing an enemy plane about to make a dive at us, tapped the shoulder of the chief pilot, directing him to turn left or right.” Yamamoto’s and Ugaki’s aircraft separated as they accelerated into their dives, the distance between them increasing as the No. 1 plane banked to the right, south-southwest toward the shoreline while the No. 2 plane banked east to the left.

As Ugaki’s plane separated from the lead bomber he lost track of Yamamoto before finally locating the C-in-C’s Betty. He was horrified to see the airplane, now skimming the jungle top, belching smoke and losing speed as it headed south. Ugaki ordered air staff officer Muroi, who was standing in the gangway diagonally behind him, to keep an eye on the C-in-C’s plane, then turned to the pilot, shouting, “Follow plane No. 1! Follow plane No. 1!”

Hayashi, who was performing desperate escape maneuvers, sometimes using only his feet and sometimes only his hands as he banked the plane and put it into sharp turns, had also lost sight of the other bomber. “Tracers flashed by our wings, and the pilot frantically maneuvered to evade the pursuing fighter plane,” Ugaki recalled. “I waited impatiently for the airplane to return to horizontal position, so that I could observe the admiral’s bomber. Although I hoped for the best, I knew only too well what the fate of the airplane would be.” His premonition was correct. Yamamoto’s plane was no longer in sight; dominating the horizon was a column of black smoke boiling from the dense jungle into the air. His despair in that moment suffuses his diary entry: “Alas! It is all over!”

We Killed Yamamoto is published by Osprey Publishing and is available to order here.

Photo credit: Adam Tooby via Osprey, U.S. Navy