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 18, 1943, a flight of 16 Army Air Forces twin-engine Lock­heed P‑38 Light­ning fighters from Kukum Field on Guadal­canal am­bushed Yama­moto’s green-striped Mitsu­bishi G4M Betty medium bomber as it approached Balalae Air­field on an island near 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. The next day a Japa­nese search-and-rescue party hacked its way to the jungle crash site and Yama­moto’s body, which had received two 0.50-caliber bullet wounds, one through the head. The admiral’s 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