Each day, messages like these were deciphered and a summary was typed on special paper with TOP SECRET printed at the top and bottom. The intelligence from the Purple machine came to be known as “Magic,” likely because Friedman’s Army bosses referred to the team as their magicians. The Magic summaries were put in a briefcase and taken by a messenger to the few people with the clearance to see them. When intelligence was attributed to a “highly reliable and trusted source,” this usually meant it came from Magic. In a 1944 memo, the Army noted that the Purple messages were “the most important and reliable source of information out of Europe.” The sheer quantity was overwhelming to the translators who worked closely with the code breakers, converting messages from Romaji to English. “Through their almost na?ve confidence in the security of their cryptographic systems, the garrulous Japanese unwittingly admitted us into many of their most solemn conclaves,” noted one internal history of the translating unit. Between 1943 and 1945, more than ten thousand Purple messages were delivered to American military intelligence.
For a time, the Purple break would exacerbate the rivalry between the U.S. Army and Navy. After the machine was broken by Friedman’s team, the Navy figured out how the Japanese were varying the key settings, and thus how to predict them. So eager were the two services for credit that an absurd compromise was reached in which the Navy took responsibility for breaking Purple ciphers on odd days, and the Army on even, so that neither would have an “unfair advantage.” This led to wrangling about whether “even” meant the day a transmission was sent or the day it was received. For important transcripts, both services would crack them and race to be the first to deliver them.
In April 1941, seven months after her historic break, Genevieve Grotjan received a raise of $300 and a promotion to “principal cryptographic clerk.” Friedman’s team rapidly began to expand. The Purple machine could not predict the attack on Pearl Harbor, for the simple reason that Japanese diplomats were not clued in by their military as to what was about to happen; a fourteen-part message containing a precisely worded communication (in English) ending negotiations was deciphered by the Americans, it’s true, but it did not give concrete warning of a naval attack. At the time, there were 181 code breakers working downtown for the Army. More began to pour in. The Munitions Building outlived its purpose—for everybody in it. The War Department prepared to move into the Pentagon, now under rapid construction. Friedman’s operation also needed to relocate. The boom and expansion of the country’s military administration had begun.
By then, a clandestine Army intercept station was being established in a converted barn at a place called Vint Hill Farms in the Blue Ridge Mountain foothills. Driving back from a tour of the proposed installation, a group of Army officials noticed the spacious grounds and elegant buildings of a place called Arlington Hall Junior College, where, as it happened, the code breakers Delia Taylor and Wilma Berryman had rented rooms one summer, when the school was offering itself as a “resort hotel” in a vain effort to stay solvent. The two-year finishing school—offering lessons in music, typing, homemaking, posture, and other subjects to girls of “good character” and deportment—was not yet twenty years old and had never been financially sound, nor well regarded in terms of academics. It had gone bankrupt during the Depression, and now war had decimated attendance.
The school lay nestled in a central part of the small county, on former swamp-and pastureland situated near the villages of Ballston and Clarendon, along an old streetcar line that connected Washington with Falls Church in an era when residents fled the city in the dank and awful summers for the barely more hospitable suburbs. The streetcar line had been replaced by a thoroughfare for cars. The one-hundred-acre grounds included a hunt course, riding rings, a hockey field, a golf course, cottages, and a teahouse. The location was convenient to Washington but far enough away to escape enemy bombing and the notice of secret agents. There was talk of putting the Signal Intelligence Service in the Pentagon, a few miles away, but space there was a concern, and the code breakers felt it would be better not to have the military breathing down their necks.
And so the thing was done. The War Department filed a Declaration to Take and paid $650,000, which was less than the Arlington Hall trustees wanted. The faculty and 202 students were evicted.
On June 14, 1942, a small guard detail including one Army second lieutenant armed with a.45 pistol and fourteen enlisted men shouldering sawed-off broomsticks took possession of Arlington Hall. Rifles were in short supply. The move was so hasty that schoolgirls were still clearing out their rooms. Convoys of vans secretly departed the Munitions Building, transporting machines and file cabinets stuffed full of intercepts. The intent was that the very existence of Arlington Hall not be mentioned outside its gates, but in time-honored government fashion, a press release was accidentally issued. The sunny ground floor of the Colonial-style main schoolhouse had formal drawing rooms and parlors, along with a chapel, a library, and an auditorium with a concert grand piano and pipe organ. There were dorm suites on the second and third floors, and classrooms on the fourth. Code breakers set up operations in the suites, storing intercepts in bathtubs. Some dorms still had beds and dressing tables that had to be moved. Oriental carpets were rolled up, curtains dismantled, and “the finishing school atmosphere was shattered by a regime of brisk efficiency,” as one memo put it. Fences were erected, guard stations built.
The Purple machine was installed on the second floor but had to be draped whenever somebody who was not working on Purple used the nearby bathroom. People were allowed to do so once every hour. When the tabulating machines proved too heavy for an upper floor, they had to be moved to the basement—and then to new buildings. The indoor riding hall was paved with concrete and used for storage.
At Arlington Hall, Genevieve Grotjan would stay abreast of modifications and changes to Purple, with a colleague, Mary Jo Dunning. The two women became familiar with the intricacies of the Japanese diplomatic cipher; it became like an old friend. As the war wore on, a number of other ciphers were attacked, and Grotjan would be dispatched to solve challenges they presented.