During World War II, the Army recruited large numbers of women for the Women's Army Corps who were deployed where they were needed most. Since General Douglas MacArthur believed that women were well suited to cryptologic work, a very large contingent of WACs were sent to his theater of war, the Southwest Pacific.
One of the WACs deployed to the Southwest Pacific was a woman we will call Sue. Sue was initially trained as a lab technician, but was selected to be sent to Vint Hill Farms near Warrenton, Virginia for cryptologic training. Her father had served in the Navy in the First World War and his service inspired Sue to serve in the military as well.
At Vint Hill Farms, Sue learned elementary cryptography, the basics about US cryptologic systems, and how to solve Japanese systems. Sue and her classmates were part of a group that were going overseas, so they also received deployment training at Oglethorpe, Georgia; in later years Sue reminisced about gas mask training and learning how to climb down cargo nets.
Sue and her WAC detachment spent 26 days steaming across the Pacific, and arrived in the Southwest Pacific just as American forces were landing in the Japanese-occupied Philippines. They ended up on the island of Morotai, at Lake Sentani, just below General MacArthur's headquarters. The WACs were assigned to work for Central Bureau, the cryptologic support unit for the Southwest Pacific Theater.
The WACS were assigned Japanese encrypted messages, often shipping messages. The message wording in Japanese communications had been converted to numbers from a codebook and then the codebook numbers were super-enciphered with numbers from an additive table. Some of the WACs worked to subtract the additives and get down to the codebook numbers; others worked at "bookbreaking," i.e., trying to recover the Japanese word (such as maru, a designator for a ship) in the original codebook.
The WACs had learned a few Japanese words to assist in their analysis, but, once their work was done, the Japanese message was passed to a linguist for translation.
Outside of the detachment, life at Lake Sentani wasn't all work. The single WACs often dated servicemen from nearby camps. Sue recalled that their dates were required to have a vehicle and a sidearm and pass through three checkpoints to be able to pick up the ladies who lived in tents.
Once U.S. forces recaptured the Philippines, Central Bureau personnel moved to San Miguel in the islands. They were stationed at a former sugar plantation and were upgraded to billeting in Filipino-style houses.
To learn more about cryptologic greats, visit the National Cryptologic Museum at the intersection of Maryland Route 32 and the Baltimore-Washington Parkway (I-295), adjacent to the headquarters of the National Security Agency. Admission and parking are free. Click here (for hours, directions and other information. You can also follow the museum on Facebook.