Rabaul, New Britain Island, Papua New Guinea April 13, 1943

On this date in 1943 the headquarters of Adm. Isoroku Yama­moto on Rabaul, the impor­tant Japa­nese garri­son on New Britain Island in the Bis­marck Archi­pel­ago, sent a coded mili­tary radio signal to various Jap­anese com­mands in the Western South Pacific. The mes­sage listed the dates and schedule of the admiral’s upcoming inspec­tion tour of the Solo­mon Islands and New Guinea as well as the num­ber of trans­port planes and fighter escorts in his party. The widely revered Yama­moto was the com­mander in chief of the Com­bined Fleet of the Impe­rial Japa­nese Navy and the planner of the Decem­ber 7, 1941, sur­prise attack on the U.S. Pacific Fleet anchored in Pearl Harbor, Hawaii. By spring 1943, how­ever, the for­tunes of Japa­nese armed forces in the Western South Pacific were sinking. U.S. Marines and Army soldiers had recently captured the island of Guadal­canal in the Solo­mon Islands chain after a six-month cam­paign (August 1942 to Febru­ary 1943) despite the terri­ble sac­rifice of 38 Japa­nese ships, 638 air­craft, and 19,200 dead. Stung by criti­cism that senior com­man­ders were not visiting the front to as­certain the situ­a­tion and turn things around, Yama­moto resolved to pay the first of his visits to naval air units on Bougain­ville, the largest island in the Northern Solomons (see map below).

The Yamamoto radio message was sent in the new JN-25D naval code variant, but that didn’t stop Amer­i­can crypt­an­alysts from deciphering it in less than a day. Adm. Chester Nimitz, the U.S. com­man­der in the Pacific, autho­rized the oper­a­tion to shoot down Yama­motos’s air­plane; he con­sid­ered killing an enemy officer, even the highest-ranking offi­cer in the Impe­rial Japa­nese Navy, purely a milit­ary matter. (There is no official record of U.S. President Franklin D. Roose­velt authorizing the Navy Depart­ment to kill Yama­moto.) The fiery U.S. Pacific Fleet com­man­der William “Bull” Halsey issued his own com­mu­niqué to con­vey to the designated assassins: “TALLY HO X LET’S GET THE BASTARD.”

The end came for Yamamoto exactly a year after the famous Doo­little Raid on Tokyo. On April 8, 1943, a flight of 16 Army Air Forces long-range, twin-engine, twin-boom Lock­heed P‑38 Light­ning fighters from Kukum Field on Guadal­canal am­bushed Yama­moto’s green-striped Mitsu­bishi G4M Betty medium bomber as it, along with its fighter cover and a second Betty, approached Balalae Air­field on Shortl­and Island just south of Bou­gain­ville. The air­men had managed to do this with­out the aid of radar, instead inter­cepting their prey by cal­cu­lating the speed of the Betty bomber trans­ports (there were two), pro­bable wind speed, the enemy’s pro­bable flight path, and Yama­moto’s repu­ta­tion for arriving on the dot. One Betty bomber trailing heavy black smoke crashed in Bou­gain­ville’s dense jungle, the other crash-landed in the ocean, where three survived. The next day a Japa­nese search-and-rescue party hacked its way to the jungle crash site and Yama­moto’s body, belted upright in his seat and still holding his jeweled samurai sword. The admiral had received two 0.50‑caliber bullet wounds, one in the back of his neck. His staff cremated his remains and for­warded the ashes to Tokyo aboard his last flagship, the super battleship Musashi.

On June 5, 1943, Yamamoto was given a full state funeral. Amid the mil­lion mourners Showa Emperor Hiro­hito pro­moted the fallen admiral to Marshal Admiral (admiral of the fleet) and awarded him the Order of the Chry­san­the­mum (1st Class). The German govern­ment, Japan’s Axis ally, post­hu­mously awarded Yama­moto the Knight’s Cross of the Iron Cross with Oak Leaves and Swords, the only foreign recip­i­ent to receive that honor. Con­versely, Amer­i­cans greeted Yama­moto’s death, when it was publicly announced on May 21, 1943, as sweet pay­back for his role in ini­ti­a­ting the war between America and Japan. The U.S. Navy awarded the Navy Cross to pilots of the “killer flight.”

Adm. Isoroku Yamamoto (1884–1943): Japan’s Naval War Leader

Map of Papua New Guinea, the Bismarck Archipelago and the Solomon Islands

Above: This map shows the route of Adm. Isoroku Yama­moto’s planned two-hour flight on April 18, 1943, from the major Japa­nese base at Rabaul on New Britain to a Japa­nese naval base on the small island of Balalae near Bou­gain­ville. The U.S. Army Air Forces’ daring top-secret kill mis­sion, Oper­a­tion Ven­geance, succeeded in shooting down both of Yama­moto’s trans­port bomber air­craft as he and his party were en route to visit naval air bases in the Solo­mom Islands and New Guinea. The death of the “Archi­tect of the Pacific War” raised the morale of Allied forces and the Amer­i­can people and damaged the morale of the Japa­nese (“an insupport­able blow”), especially those serving in the Imperial Japanese Navy.

Yamamoto at naval planning meeting, 1940Yamamoto saluting naval pilots on Rabaul, April 18, 1943

Left: In 1939 Yamamoto was promoted to admiral and sent to sea as com­mander in chief of the Japa­nese Com­bined Fleet. He is shown here aboard his flagship, the battle­ship Nagato in 1940. Yama­moto had vig­or­ously warned against war with the United States, where he had served his country as a naval attaché in Wash­ing­ton from Janu­ary 1926 to March 1928. Yet, patriot to the core, when he was ordered to fight, he waged war with a ven­geance beginning with an attack on the U.S. Pacific Fleet at Pearl Harbor, Hawaii, that he and his staff had been plan­ning since early 1940. In the first half of 1942 power­ful Japa­nese naval for­ma­tions sup­ported thrusts against poorly defended Amer­i­can, British, Aus­tra­lian, and Dutch in­ter­ests in the Pacific. The naval Battles of the Coral Sea (May 4–8, 1942) and Midway (June 4–7, 1942) ended six months of Japa­nese ascen­dancy. The U.S. cam­paign on Guadal­canal (August 1942 to Febru­ary 1943) forced Japan into a war of attri­tion, and Yama­moto sensed this before his death on April 18, 1943. The island-hopping cam­paign by the U.S. and its allies that began with invading Guadal­canal took Allied forces to the shores of Japan itself.

Right: Yamamoto saluting aviators just before en­planing on his ill-fated flight to Bou­gain­ville, where he had planned face time with offi­cers, the sick and wounded and salu­ting his warriors. Yama­moto had given him­self a year to deprive the U.S. of the naval capa­city to oppose Japa­nese expan­sion in South­east Asia and the Pacific. But time had definitely run out for him and his emperor after Amer­i­can crypt­an­a­lysts had broken Japa­nese naval codes and used the decrypts to pene­trate IJN’s plans and those of Yama­moto’s April 18 visit. After the four pilots assigned to the “killer flight” had dis­patched Yama­moto’s trans­port bomber to a jungle grave and the other bomber to a watery grave, the leader of the 339th Fighter Group that flew the avenging P‑38 Light­nings radioed Guadal­canal that the “son of a bitch” would never again threaten America.

Contemporary U.S. and Japanese News Footage of the Shoot-Down of Adm. Isoroku Yamamoto, April 18, 1943