Commendation

Op-20-G-md
(SC)N36-1

MEMORANDUM FOR OP-20:

Subj: Equipment for Decryption of Japanese Strip Cipher.

Encl: (A) DNC Memo to CinC, U.S. Naval Computing Machine Laboratory, Dayton, Ohio, Serial 1423620.
(B) CinC, U. S. Naval Computing Machine Laboratory, Dayton, Ohio, Ltr. to Chief of BuShips, dated 16 January 1945.

1. The Japanese strip system recently introduced makes use of 48 Kana strips. Thirty of these strips are selected from a stock of 100. Certain of the strips are omitted while others are turned over. One interesting variant is the use of a transparent plastic strip board which permits hourly change from obverse to reverse side of the board. Hand methods of deciphering of this system are extremely laborious.

2. A project was initiated on 16 December 1944 to build a machine which would accomplish the complicated process of decipherment directly from a keyboard to a page copy. This equipment involves over 1,000 relays 50,000 soldered connections, stepping switches, controls, etc. Less than 30 days elapsed between the original inception of the project and the completion of the equipment which is now in operation in our Pacific section. Original rough designs were prepared by our research group. The equipment was designed, fabricated, wired, and assembled by naval personnel attached to the U.S. Naval Computing Machine Laboratory, Dayton, Ohio.

3. The personnel most intimately connected with the project put forward tremendous efforts in making the equipment quickly available. It is suggested that enclosure (A) be forwarded as a commendation to the personnel most intimately concerned. Enclosure (B) will be forwarded by the Bureau of Ships for inclusion in the service records of these personnel.

J.N. Wenger
Commander, U.S. Navy

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    WHO worked during the war? Find the Personnel section. Also, Joseph R. Desch
    WHAT were their goals? By the Numbers. Also, The US Bombe
    WHY? History of the Bombe Project A contemporary account of the reasons and the plans for their project for the Director of Naval Communications, 1944.
    WHERE was the project: In Dayton, it was in Building 26. In Washington, it was housed at the Naval Communications Annex

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    • Stray Thoughts in the Information Age

      General George S. Patton, the legendary commander of World War II, became an astute consumer of communications intelligence (COMINT); he learned its worth in the drive across Western Europe after D-Day and used it well. For example, in mid-August 1944, while Patton’s Third Army was located near the French city of Le Mans, the general and about 40 of his officers attended daily intelligence briefings. Here they would hear regular briefings by the G-2 (Intelligence) and G-3 (Operations), situation reports, and a news report from radio broadcasts. Following each meeting, all but seven officers were dismissed, and the rest stayed for a briefing on the enemy situation as seen in COMINT. This source proved valuable for the Third Army: ULTRA (the codeword assigned to COMINT derived from decryption of high-level German ciphers) material alone predicted a drive by five German Panzer divisions against the Third Army at Avaranches. In another instance, when Third Army headquarters moved near Chalons, an ULTRA message arrived at 0100 hours showing the German order for an attack at 0300. Patton had described the U.S. troops in the attack areas as spread out as “thin as the skin on an egg.” He found means to alert the defending divisions without jeopardizing the security of ULTRA, and the German attack was repulsed.

      One member of Patton’s staff wrote about the value of ULTRA to Patton’s army stating that, “An army has never moved as fast and as far as the Third Army in its drive across France, and ULTRA was invaluable every mile of the way.”

      NSA, Center for Cryptologic History, from 50th Anniversary Brochure, p. 10. URL frequently change but currently this can be found at nsa.gov > History > Cryptologic History > Publications > NSA/CSS. /p>

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