Deception

Deception is the art of planting false or misleading information that is sufficiently convincing to fool the enemy's intelligence apparatus. It can be used to mislead the enemy regarding either capabilities or intentions. This in turn increases the likelihood of successfully achieving surprise. 

Since enemy intelligence is likely already flooded with a mass of observations, from which they must somehow sift the few observations of real value, one need not plant much false information to make the enemy's task harder. However, there is always the risk that the deception will be detected and give the enemy genuine clues to one's own intentions. This risk can be minimized by planting some true but out of date or otherwise useless information in order to give the sources of false information greater credibility. Sources of false information during the Pacific War included simulated radio traffic to mislead enemy traffic analysis; deployment of dummy aircraft or tanks to attract the attention of enemy reconnaissance; and use of double agents to return false or misleading human intelligence. Allied troops headed for the Aleutians were lecture on tropical diseases and senior officers allowed themselves to be seen studying charts of the Atlantic or the Argentine coast in hopes of planting false rumors about their destination.

The best deception schemes played to the enemy's prejudices, and if one's own intelligence service was reading enemy codes, it was possible to closely monitor the effect that deception schemes were having on the enemy's thinking and adjust accordingly.

Diversion is a form of deception in which a small force is employed in a way intended to create the impression that a larger force is present and poses a serious threat. Artillery diversions were bombardments on enemy positions against which no infantry attack was planned, for the purpose of tricking the enemy into committing his reserves where they were not needed or to induce the enemy artillery to open fire and thus reveal its positions for counterbattery fire. The Japanese used deceptive fire at Singapore, where fire from a few widely dispersed guns was directed against Changi to deceive the British into believing that the bulk of the Japanese artillery was targeting this area as the crossing point from the mainland. The actual crossing point was some distance further west.

Allied Deception

One of the first successful Allied deception operations was the seaplane raid by Tangier against Tulagi on 20 May 1942. This helped persuade the Japanese that the American carriers were still in the South Pacific rather than preparing to meet the Japanese at Midway.

Another was the raid by Boise on the Japanese picket boat line east of the Japanese home islands. This took place at about the same time as the Guadalcanal landings and succeeded in diverting some of Japan's land-based naval aircraft to protect against the possibility of a Doolittle-style carrier raid. This may have slowed the Japanese reaction to Guadalcanal by a few precious days. On the other hand, the concurrent diversionary raid on Makin was almost completely unsuccessful.

Another successful Allied deception was Kenney's clever scheme to quietly construct a fighter strip at Tsili Tsili while Japanese attention was drawn to deliberately exaggerated construction work at Bena Bena. This allowed the Alies to launch a surprise attack against Wewak that neutralized this major Japanese airfield complex.

During the New Guinea campaign, the Allies deliberately floated a rubber raft ashore at Hansa Bay containing a notebook with false information suggesting an imminent landing. This was followed up with supply drops inland. The Japanese responded by massing men and material at Hansa Bay, which the Allies intended to bypass. One of the participants in this operation later became the executive officer of the Alamo Scouts.

Feints became an almost stereotypical part of Allied landing plans from 1944 on. Typically the reserve elements of an invasion force would make a demonstration off a plausible landing beach some distance from the real landing beach. This tactic was highly successful at Tinian, but the Japanese usually refused to be fooled (as at Saipan) or did not attempt to defend any landing beach (as at Okinawa.)

Prior to the second Philippines campaign, the Allies attempted to deceive the Japanese on their next move by raiding Marcus Island (to suggest a climb up the Bonins ladder) and the Nicobar Islands (to suggest a move against Malaya or the Netherlands East Indies.) The Marcus operation was particularly elaborate, making use of smoke, dummy radar targets, flash lamp floats, and pyrotechnics to create the impression of a large invasion force. Neither deception effort had the least effect on the Japanese, to whom it was obvious that the Philippines were the next target.

Starting in 1943, U.S. ships began to be painted with camouflage patterns designed to break up the outline of the ship, making it more difficult for hostile observers to correctly identify the ship type, distance, course, and speed, as illustrated in the photograph at the top of this article. 

Perhaps the largest deception operation in the war against Japan was carried out by Slim during the Burma campaign of 1944. One of Slim's corps engaged in highly visible preparations across the river from Mandalay and held the attention of the Japanese while a second corps, operating under radio silence, passed south through the rugged Myttha Valley behind a screen of East African troops (28 East African Brigade). This screening force was chosen because the Japanese already knew that 11 East African Division was operating in the area and the presence of additional African troops might not be regarded as significant. The corps was able to cross the Irrawady well south of Mandalay and take the Japanese by surprise.

Another deception operation was the visit to England by a single B-29, which was inspected by Eisenhower and Doolittle and was permitted to be photographed on the ground by a German reconnaissance aircraft. This was to lead the Axis to believe the much-publicized B-29 was going to make its debut in the Normandy invasion rather than in the Far East.

One of the oddest deception experiments of the war was Project Yehudi, which sought to make aircraft more difficult for submarines to spot in daylight. It was based on the observation that even a white-painted aircraft appeared as a dark silhouette against the sky when it approached at low altitude. The proposed solution was to install a strip of floodlights along the wings and on the forward fuselage, with a bluish tint painted over the lights to simulate the normal low-sky spectrum. This proved astonishingly effective in trials in January 1944, making an Avenger normally detectable at 12 miles (20 km) undetectable up to 3000 yards. However, the Yehudi effect required careful calibration of the lights and the filter tint and proved unreliable under changing weather conditions, and was not put into operational use before the war ended.

Training video on camouflage

Japanese Deception

Japanese deception operations at the start of the Pacific War were often highly effective. For example, no real attempt was made to conceal convoys headed to Malaya just as war broke out. This had the effect of drawing the attention of the Allies away from Hawaii, which was being quietly approached by the Pearl Harbor Attack Force.

The Japanese also made use of false radio traffic in an effort to deceive the Allies. This may have contributed to the success of early attacks, but it became increasingly counterproductive as Allied cryptanalysts made deeper inroads into Japanese codes.

In addition to broadcasting false military radio traffic, Nakano School agents of Tomi Kikan used the powerful transmitters at Saigon during the Netherlands East Indies campaign to broadcast faked Dutch news reports, being careful to duplicate the voices and mannerisms of authentic Dutch announcers as closely as possible. These succeeded at times at misleading the Allies, but also misled Tokyo monitors on at least one occasion.

Japanese naval plans typically included feints, with several task forces converging on targets from different directions in an elaborate dance meant to bedazzle and confuse the Allies. Allied code often uncovered the feints, to the great disadvantage of the Japanese, since the practice of dividing their force into task forces too distant to support each other invited defeat in detail, as at Midway.

As the Allies gained control of the air, the Japanese made greater use of deception at their airfields. Aircraft were widely dispersed and heavily camouflaged, and American pilots who struck Heito airfield on Formosa on 9 January 1945 reported that most of the aircraft there appeared to be dummy aircraft. However, such deception put the aircraft so far from the runways that it took considerable time to bring the aircraft from their camoflaged revetments to the runways and prepare them for takeoff.

References

Hastings (2016)
Hess et al. (1998)

Inoguchi, Nakajima, and Pineau (1958)

Lundstrom (2006)

Lewin (1976)

Mercado (2002)

Morison (1958, 1959)
Prados (1995)

Roscoe (1953)

Wolk (2010)

Zedric (1995)

The Pacific War Online Encyclopedia © 2009-2012, 2014-2015,2017 by Kent G. Budge.  Index

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