V-J Day: Remembering the 509th Composite Group missions that hastened the end of World War II

  • Published
  • By Dee Gullickson
  • 509th Bomb Wing Historian

On July 17, 1945, the fate of the world was in the hands of three men.

U.S. President Harry S. Truman met with British Prime Minister Winston Churchill and Soviet Premier Joseph Stalin during the meetings now known as the Potsdam Conference. The leaders of the three countries (Clement Attlee succeeded Churchill as Prime Minister on July 26th) spent the next two weeks discussing the state of post-war Europe following the German surrender on May 8 and the ongoing war in the Pacific theater.

Stalin’s Soviet Union had not yet declared war on Japan and the lack of a common enemy in Europe led to difficulties reaching consensus – but the meeting ultimately paved the way for victory in the Pacific. Signed by Truman, Churchill, and Chaing Kai-shek of China, the Potsdam Declaration called for the unconditional surrender of Japan.

The declaration opened with the statement,

“We - the President of the United States, the president of the National Government of the Republic of China, and the Prime Minister of Great Britain, representing the hundreds of millions of our countrymen, have conferred and agree that Japan shall be given an opportunity to end this war.”

Among the stipulations for surrender were assurances that the people of Japan would not be enslaved and once disarmed, the military would be free to return to their homes in peace. The last line of the declaration, however, made clear the Allies’ intent should Japan not agree to the terms:

“The alternative for Japan is prompt and utter destruction.”


A “group” effort to end the war

Meanwhile, on the remote Pacific island of Tinian members of the 509th Composite Group, the precursor to today’s 509th Bomb Wing, continued preparing for the mission they had been training for since the group’s activation at Wendover Field, Utah, in December of the previous year.

Organized to be self-sufficient, the group was composed of the 393rd Bombardment Squadron, with the tactical role of flying the unit’s B-29 Superfortresses, and the 1st Ordnance Squadron, which held the key to operations as the unit overseeing the special weapons. The 390th Air Service Group, “a group within a group,” with its 603rd Air Engineering and 1027th Air Materiel Squadrons covered housing and other logistical matters while overseas and the 1395th Military Police Company provided security for the project. Additionally, the 320th Troop Carrier Squadron was charged with rapidly transporting men and supplies to and from various locations, including the group’s move from Utah to Tinian.

Atomic Might

When Japan refused to accept the terms outlined at Potsdam, it was time for the 509th Composite Group to step into action. The Group conducted four missions to mainland Japan using pumpkin-shaped conventional weapons, with varying degrees of success.

Delivering the first of two historic strikes, Col. Paul Tibbetts piloted the B-29 Enola Gay over the city of Hiroshima, headed for a point just below the Japanese Army Division Headquarters. On Aug. 6, 1945, his crew dropped the atomic bomb “Little Boy,” which detonated approximately 1,900 feet above the city with the force of 15,000 tons of TNT and destroyed almost five square miles of the city.

Truman addressed the American public in a radio broadcast later that day announcing the bombing and once again calling on the Japanese to surrender.

Aviators with the 509th returned to the skies Aug. 8 and carried out another non-atomic mission over mainland Japan, striking five targets. When no surrender was offered, Maj. Charles Sweeney piloted the crew of the B-29 named Bockscar to Nagasaki, where they dropped the second atomic weapon, “Fat Man,” Aug. 9.

The mission originally planned to attack the arsenal at Kokura and diverted an alternate target due to poor weather. In Nagasaki, the bomb hit an industrial area that included the Mitsubishi Steel and Arms Works and the Mitsubishi-Urakami Torpedo Works – the same location that manufactured the torpedoes used in the attack against Pearl Harbor.

Although the force of the bomb was greater than that of Little Boy, the destructive power equivalent to 21,000 tons of TNT was contained to a smaller area because of the hilly terrain of the city. The next day, Japan sent a message to the United States discussing the terms of surrender.

Even following the second bombing, some leaders within the Japanese military wanted to fight on – but their emperor knew the war was lost. On Aug. 15, Emperor Hirohito addressed his nation in a radio broadcast informing them of his decision to end the war. To this day, Great Britain and South Korea commemorate the end of the war against Japan on this day.

The United States instead designated Sept. 2 as V-J Day, commemorating the day the Japanese delegation signed the formal surrender agreement aboard the USS Missouri anchored in Tokyo Bay - finally ending World War II once and for all.

In the end, the tragic estimates range from 50 to 80 million uniformed combatants and civilians killed worldwide during the conflict.

Following the atomic missions, a member of the Composite Group penned a poem titled “Atomic Might.” One line in particular sums up the moment the men of the 509th fulfilled their mission and dealt the final blow to the Empire of Japan, thereby ending the war:

"From out of the air the secret fell
And created below a scene of hell,
Never before in times fast flight
Has there been displayed such a sight,
As the thunderous blast, the blinding light,
Of the 509th’s atomic might."