How the American Women Codebreakers of WWII Helped Win the War

 Thousands of women tirelessly worked in close quarters throughout the war breaking codes for the Army and Navy. Vowed to secrecy, they have long gone unrecognized for their wartime achievements. (National Archives and Records Administration)

Thousands of women tirelessly worked in close quarters throughout the war breaking codes for the Army and Navy. Vowed to secrecy, they have long gone unrecognized for their wartime achievements. (National Archives and Records Administration)

The first American to learn that World War II had officially ended was a woman.

The Army and Navy's code breakers had avidly followed messages leading up to that fateful day. Nazi Germany had already surrendered to the Allies, and tantalizing hints from the Japanese suggested that this bloody chapter of history might soon come to an end. But when U.S. Army intelligence intercepted the Japanese transmission to the neutral Swiss agreeing to an unconditional surrender, the task fell to Virginia D. Aderholt to decipher and translate it.

Head of one of the Army's language units, Aderholt was a master at the cipher the Japanese used to transmit the message—teams crowded around her as she worked. After the Swiss confirmed Japanese intent, the statement was hurried into the hands of President Harry S. Truman. And on the warm summer evening of August 14, 1945, he made a much-anticipated announcement: World War II was finally over.

Throngs of Americans took to the streets to celebrate, cheering, dancing, crying, tossing newspaper confetti into the air. Since that day, many of the men and women who helped hasten its arrival have been celebrated in books, movies and documentaries. But Aderholt is among a group that has largely gone unnoticed for their wartime achievements.

She is just one in upwards of 10,000 American women codebreakers who worked behind the scenes of WWII, keeping up with the conveyor belt of wartime communications and intercepts. These women continually broke the ever-changing and increasingly complex systems used by the Axis Powers to shroud their messages in secrecy, providing vital intelligence to the U.S. Army and Navy that allowed them to not only keep many American troops out of harm's way but ensure the country emerged from war victorious.

The information they provided allowed the Allied forces to sink enemy supply ships, gun down the plane of Isoroku Yamamoto, the architect of Pearl Harbor, and even help orchestrate the invasion of Normandy. During the later years of war, the intelligence community was supplying more information on the location of enemy ships than American servicemen could keep up with.

"The recruitment of these American women—and the fact that women were behind some of the most significant individual code-breaking triumphs of the war—was one of the best-kept secrets of the conflict," writes Liza Mundy in her new book Code Girls, which finally gives due to the courageous women who worked in the wartime intelligence community.

Some of these women went on to hold high-ranking positions—several even outranking their military husbands. Yet to this day, many of their families and friends never knew the instrumental role they played in protecting American lives.

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Mundy happened upon the story while her husband was reading Robert Louis Benson and Michael Warner's book on the Venona project, a U.S. code-breaking unit focused on Russian intelligence during WWII and the Cold War. One particular detail of Venona surprised Mundy: the project was mostly women.

Curiosity piqued, she began digging into the topic, heading to the National Cryptologic Museum and the National Archives. "I didn't realize at that point that the Russian codebreaking women were just a tiny part of a much larger story," she says. "I thought I would spend a week in the archives. Instead, I spent months."

Mundy, a New York Times bestselling author and journalist with bylines in The AtlanticThe Washington Post and elsewhere, dug through thousands of boxes of records, scouring countless rosters, memos and other paper ephemera. She filed declassification reviews, which turned up even more materials. "It turned out that there was a wonderful record out there, it just had to be pieced together," she says.

Mundy even tracked down and interviewed 20 of the codebreakers themselves, but for some it required a bit of cajoling. During the war, it was continually drilled into them that "loose lips sink ships," she says. And to this day, the women took their vows of secrecy seriously—never expecting to receive public credit for their achievements. Though many of the men's tales have leaked out over the years, "the women kept mum and sat tight," she says.

"I would have to say to them, 'Look, here are all these books that have been written about it,'" Mundy recalls. "The NSA says it's okay to talk; the NSA would like you to talk," she would tell them. Eventually they opened up, and stories flooded out.

Read the full story at Smithsonian.com