Code Girls: The Untold Story of the American Women Code Breakers of World War II

by Liza Mundy

Nearly half of the men who died were on the Arizona, among them twenty-three pairs of brothers.

Congress declared war on Japan the next day. Germany—Japan’s ally—declared war on the United States three days later.

Emerging from two decades of disarmament and isolationism, America had a clubby Navy with a disorganized intelligence apparatus; a small skeleton Army; no freestanding Air Force; and—as hard as this may be to believe, in this era of proliferating and overlapping spy agencies—barely any spies abroad. Building an overseas spy network would take time.

German U-boats had attacked shipping up and down the Atlantic coast. On the New Jersey shore, where her family spent summers, bits of shipwreck would wash up and they could hear guns booming. It did not seem out of the question that Japan would invade the U.S. mainland—Alaska, even California—or that America would come under fascist domination.

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. The military and strategic importance of their work was enormous.

After the war, the U.S. Army and Navy code-breaking operations merged to become what is now the National Security Agency. It was women who helped found the field of clandestine eavesdropping—much bigger and more controversial now than it was then—and it was women in many cases who shaped the early culture of the NSA.

“In the event of total war,” Noyes told her, “women will be needed for this work, and they can do it probably better than men.”

The instructors would be given a few texts to jump-start their own education, including a work called Treatise on Cryptography, another titled Notes on Communications Security, and a pamphlet called The Contributions of the Cryptographic Bureaus in the World War—meaning World War I, the so-called war to end all wars.

Disparate as their backgrounds were, the women who answered these summonses—that of the Navy and that of the Army—had a handful of qualities in common. They were smart and resourceful, and they had strived to acquire as much schooling as circumstances would permit, at a time when women received little encouragement or reward for doing so. They were adept at math or science or foreign languages, often all three. They were dutiful and patriotic. They were adventurous and willing. And they did not expect any public credit for the clandestine work they were entering into.

During the most violent global conflict that humanity has ever known—a war that cost more money, damaged more property, and took more lives than any war before or since—these women formed the backbone of one of the most successful intelligence efforts in history, an effort that began before the Pearl Harbor attack and lasted until the Second World War’s very end.

There had not yet been put in place elaborate systems of regulating and credentialing—professional associations, graduate degrees, licenses, clubs, learned societies, accreditation—the kinds of barriers long used in other fields, like law and medicine, to keep women out.

They were trying to protect the very men whose lives their arrival put in danger.

That women were considered better suited for code-breaking work—as the letter that Rear Admiral Noyes sent to Ada Comstock suggested—wasn’t a compliment. To the contrary. What this meant was that women were considered better equipped for boring work that required close attention to detail rather than leaps of genius.

This was seen as women’s rightful domain: the careful repetitive work that got things started, so that the men could take over when things got interesting and hard. Men were seen as more brilliant than women, but more impatient and erratic.

One of the best code-breaking assets is a good memory, and the only thing better than one person with a good memory is a lot of people with good memories.

In 1942, only about 4 percent of American women had completed four years of college.

It was not easy being a smart girl in the 1940s. People thought you were annoying.

One electrical company asked for twenty female engineers from Goucher, with the added request, “Select beautiful ones for we don’t want them on our hands after the war.”

The Axis powers never mobilized their women to the extent that the Allies did. Japan and Germany were highly traditional cultures, and women were not pressed into wartime service in the same way, not for code breaking or other high-level purposes.

Randolph-Macon was one of a number of private colleges established in the nineteenth century to educate young women in Virginia, a state in which no public university had been willing to fully admit them until 1918. Of the state’s many well-regarded private women’s colleges—including Sweet Briar, Hollins, Westhampton, and Mary Baldwin—Randolph-Macon was said to be the most rigorous and demanding.

Code breaking required literacy, numeracy, care, creativity, painstaking attention to detail, a good memory, and a willingness to hazard guesses. It required a tolerance for drudgery and a boundless reserve of energy and optimism. A reliable aptitude test had yet to be developed.

a “jackpot effect,” where a male scientist hires women in his lab early in the development of a certain field, and these women hire other talented women, and, as a result, the field ends up with an unusually high number of women.

Inquisitor of Malta,

one message Elizebeth worked hard on turned out to be a Czechoslovakian love letter—and produced a series of books called the Riverbank Publications.

black chambers, as Europe’s clandestine government code-breaking shops were called in their Renaissance heyday.

It was in fact a message the British decoded—the Zimmermann telegram—that (along with Germany’s declaration of unrestricted submarine warfare) helped bring the United States into World War I. German foreign minister Arthur Zimmermann sent an internal coded message to Germany’s minister to Mexico, instructing him to offer the president of Mexico the territories of Texas, Arizona, and New Mexico if Mexico would ally with the German cause and invade its northern neighbor. The British broke the message in January 1917; the United States was appalled; America, as George Fabyan had foreseen, went to war.

the Signal Corps recruited U.S. switchboard operators who were bilingual in English and French and loaded them into ships bound for Europe. Known as the “Hello Girls,” these were the first American women other than nurses to be sent by the U.S. military into harm’s way.

cryptography, which is the term for code making, and cryptanalysis, the term he coined for code breaking. (The word “cryptology” embraces both.)

the 1921–1922 Washington naval conference. During this uneasy interwar period, major governments were negotiating how much naval tonnage certain countries would be accorded.

Yardley, outraged and out of a job, in 1931 published a tell-all called The American Black Chamber, which became a bestseller in the United States and Japan.

In 1919, the Anti-Saloon League succeeded in pushing through the Eighteenth Amendment. Prohibition outlawed the manufacture, transportation, and sale of alcohol, but—importantly—did not outlaw its consumption. This meant American citizens could drink alcohol if they could find a way to get it. This loophole created a tempting criminal opportunity. Foreign distillers partnered with American gangsters to ship contraband alcohol to U.S. shores.

the two could not always discuss their real work with each other, because both were deciphering secret material for different branches of a growing federal bureaucracy whose agencies were distrustful and often at odds.

the Naval Reserve Act of 1916 did it say that a naval yeoman had to be male. Thanks to that loophole, American women were permitted to enlist in the naval reserves during World War I, and the designation “Yeoman (F)” was created.

During the first global conflict of the twentieth century, eleven thousand American women served as Yeoman (F)—also called yeomanettes.

Agnes Meyer, a brilliant young teacher who would become one of the great cryptanalysts of all time.

The office was nothing to brag about—just a few rooms tucked away in a Washington eyesore known as the Munitions Building, erected in 1918 as a headquarters for the War Department. The Munitions Building and the U.S. Navy headquarters were side by side, as it happened, both constructed as “temporary” wartime structures during World War I and both still in service even now that the Great War was long over, together dominating the part of the capital city between Foggy Bottom and the National Mall. The twin buildings had concrete facades and a series of thin wings that stretched backward, perpendicular to the facade. Working in them was like working in a multistory warehouse.

“What four things were thought by Captain Hitt to be essential to cryptanalytic success?” (perseverance, careful methods of analysis, intuition, and luck)

He had identified which consonants (D, T, N, R, S) are most frequent in ordinary English and which are least frequent (J, K, Q, X, Z).

Oshima’s painstaking description of German fortifications along the French coast would be invaluable when Allied commanders were planning the D-Day invasion.

In retrospect it is easy to underestimate how fragile that period felt. The Japanese were a formidable naval foe. At the outset of the war, the Japanese Navy controlled one-quarter of the Pacific Ocean and had not lost a naval battle in more than fifty years.

The attack didn’t succeed on that level—U.S. aircraft carriers were safely out of the harbor, and some stricken battleships could be recovered and repaired—but attacks elsewhere in the Pacific followed so quickly as to feel simultaneous. Just hours after Pearl Harbor, the Japanese launched air attacks on the Philippines. They captured Guam, in the Marianas, two days later, and took Wake Island before Christmas.

the most common English letters—E, T, O, N, A, I, R, and S—

the Japanese were more vulnerable than it might have seemed. It was one thing to capture so many islands and bases, and another thing to supply and defend them.

And it was important that America’s aircraft carriers had been safely out of harm’s way during the attack on Pearl Harbor.

The Battle of the Coral Sea, from May 4 to May 8, 1942, was the first naval battle in which the opposing ships never saw each other—the fighting was all done by aircraft—and it was the first Pacific contest where code breaking played a key role in the outcome.

People worried that military service would imperil women’s femininity and render them unmarriageable.

The WAACs, coming first, bore the brunt of negative publicity, enduring gibes about their chastity and criticism of their morals and motivation for joining.

Sometimes WAVES were confronted by mothers unhappy that their sons were being sent into combat, thanks to the women coming in to work in the desk jobs. But others thought the WAVES were wonderful and would invite them home for milk and cookies or holiday meals.

Vincit qui se vincit, or “She who conquers self conquers all.”

By early 1943 many U.S. citizens were led to believe America was winning the war, or starting to. This was not wrong, necessarily, but the code breakers got a more sobering perspective in the sense that they understood the full cost.