REF 

SL-~- ~-..:.- .. -

On 1 June, Colonel John C. Arrowsmith assumed 

command of the Army Security Agency, relieving 

Brigadier General Carter W. Clarke, who left for 

assignment in the Far East. Colonel Arrowsmith 

served in this Agency as Comptroller and Deputy in 

turn before being as signed as Chief. He has had a 

long career in the Corps of Engineers and served in ' 

the Chin a-Burma-India Theater and the European 

Theater during World War ll. 

Be assumed command of the 45th Engineer Regiment on 1April1942 at Camp Blanding, Florida, and 

on 8 May was promoted to the grade of Colonel; he 

departed with this unit on 28 May for cm. From October 1942, until late in 1943 he was engaged in the 

Ledo Road Project. 

On lJf December 1942 Base Section No. 3, SOS, US 

AF, Cm, was activated and Colonel Arrowsmith was 

designated as its first Commanding Officer. 

In January 1944 he joined XXI Corps, as Corps 

Engineer, and went to ETO with the unit. In this 

assignment he saw combat service in the Rhineland 

Campaign and the Campaign of Central Europe, 

Colonel Arrowsmith was also District Engineer of 

the Berlin District and assisted in rebuilding facilities 

for U. S, troops in Berlin, 

Returning from Europe in December 1947, he was 

assigned to Fort Belvoir as Director of Research and 

Development and Commanding Officer of the Research 

and Development Laboratory. 

On 1 August 1949 he was assigned to duty with the 

Army Security Agency. 

He has attended Command and Staff School at Foi:t 

Leavenworth, Engineer School, and the Army Industrial College. His decorations include the Legion of 

Merit, the Bronze star Medal, and the Croix de Guerre 

On25 June 1943 he was made a Brigadier General with Palm. He is author of articles on sunken ships 

and was named Commanding General of the Base and Industrial Mobilization, 

Section and the Ledo Road Project. • • • • 

~ 

I 

Declassified and approved for release by NSA on 05-08-2014 pursuantto E.O. 1352a 
e 

Fooling 

REF ID:A66516 

The Enemy 

teetf.F'JBl!lN'ffALT 

THE FIRST OFA SERIES ON TACTICAL DECEPTION 

DURING WORLD WAR II 

. . . . 

NAVY COMMUNICATIONS DECEPTION OF JAPAN 

One of. the most interesting and significant instances of use of communications deception in World War 

Il was that of. the Third Fleet's attack on northern 

Japan in July, 1945. During this month the Third 

Fleet under Admiral Halsey was to begin a series of. 

operations against the mainland of Japan, designed to 

destroy enemy naval and air forces, shipping, shipyards, coastal industrial centers, and empire transportation facilities. The Japanese Air Forces, particularly the growing number of. suicide planes which 

had exacted such a heavy toll of. our naval supporting 

forces in the Okinawa campaign, constituted a real 

threat to the Fleet operations which were to supplement the increasing B-29 sorties against industrial 

targets. 

The initial offensive of the Third Fleet was a carrier based air strike against the Tokyo area on 1~ 

July. Radio silence and the usual high-speed run to 

the launching point for the strike was planned for this 

phase; the Fleet's approach to be screened by submarines under instructions to destroy without warning any enemy picket located. The second offensive 

was to be a carrier-based strike against Northern 

Hokkaido on 13 July. In order to cause the Japanese 

to misinterpret the intention of striking this second 

objective and to divert the enemy's plane strength to 

the south, tactical deception was planned. The mission of. the planned deception ope r a ti on would be to 

simulate radio transmissions of the Third Fleet supposedly in fictional movement from the Tokyo area. 

after the Tokyo attack, on U and 11 July, toward a 

southern position where strikes could be launched 

against Kyushu, and thereafter a withdrawal of the 

Fleet to the Southeast. Attempts were to be made to 

deceive enemy communication analysts by submarine 

radio transmission south of. Kyushu which were generally interpreted by enemy radio traffic analysts as one 

of the fleet "cue" immediately preceding a carrier 

strike. To complete the de c e p ti on, a heavy strike 

would be made on Kyushu by carrier-type planes actually based on Okinawa. Meanwhile, the Third Fleet 

would in fact be enroute for the as s au l t on Northern 

Honshu and Southern Hokkaido. 

4 

A deception Plan. of. this scope requires expert coordination and timing, in order that the information to 

form to the planned deception story. Complete coordination, effected by a central command organization 

ination, effected by a central command organization 

within which there is a staff cognizance of the plans 

and their implementation, is absolutely necessary as 

well as accurate radio (keyed) and voice deception. 

In the TUSCON OPERATION, this coordination required timing arrangements for ship-shore radio key and 

also for press releases, official communiques, and 

correspondent's stories, in order not to compromise 

completion of the deception. 

Background Preparation 

For Radio and Voice deception, adequate and timely preparation by well-trained personnel is essential. 

There must be particular emphasis on complete, advance analysis of all pertinent radio circuits and 

"typing" of radio operators so that there will be no 

abnormal disruption of the desired pattern of traffic. 

The first radio transmission of a deception unit normally should be from the approximate position of the 

unit to be simulated, or at a distance from the position which is roughly consistent with the elapsed time 

and normal speed of advance. Arrangements with the 

units to be simulated must be made and directive s 

must in s u r e against radio indications of the actual 

"home base" o1 those units. 

In preparation forthis particular deception operation, it was requested that the Commander in Chief 

Pacific Fleet and Pacific Ocean Area arrange for the 

carrier-type plane strike on Kyushu from the Okinawa 

base, and for the submarine radio transmissions off 

Kyushu. This request was granted and the necessary 

directives were issued. Also, especially trained communication security unit personnel were supplied to 

assist in planning and implementing the radio key and 

voice phases of the operation. 

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