In the summer of 1943, American and Canadian forces launched an amphibious assault on the north Pacific island of Kiska. Codenamed Cottage, the operation was intended to seize the last enemy stronghold on North American soil from Japanese occupiers. The assault began in the predawn hours of August 15 with a heavy coastal barrage by an armada of nearly 100 Allied warships. Intense fire support was followed by a chaotic but successful ship-to-shore movement of over 34,000 U.S. Army and Canadian combat infantrymen. For 2 long days, the invasion force slugged its way inland through thick fog and against the constant din of machinegun and artillery fire. By the time the island was declared secure, over 300 Allied soldiers lay dead or seriously wounded. Japanese casualties? There were none. The Japanese had abandoned the island almost 3 weeks prior.
How could this have happened? How could a command staff of considerable talent and intellect disregard a plethora of intelligence and execute a major amphibious assault on a deserted island? The answer might lie in a basic construct of the human thought process known as perceptual bias. Perceptual biases are experienced-based assumptions and expectations that individuals intuitively apply to the world around them.1 In his book The Psychology of Intelligence Analysis, Richard Heuer argues that all individuals assimilate and evaluate information through a personal mental model (or mindset) influenced by perceptual bias. Perceptual bias is not inherently bad. The assumptions we form through this bias allow us to process what would otherwise be an incomprehensible amount of information, but they can also set a lethal trap for unsuspecting mission planners, decisionmakers, and intelligence analysts.2
Assumptions are extremely relevant to operational planning. Joint Publication (JP) 5-0, Joint Operation Planning Process (JOPP), defines assumption as a supposition about the current situation or future course of events assumed to be true in the absence of facts.3 Assumptions that address gaps in knowledge are critical for the planning process, but the planning staff must not become so wedded to their assumptions that they reject or overlook information that is not in accord with those expectations. This article examines perceptual bias and assumption in the historical context of Operation Cottage. The pointless assault of Kiska offers a valuable lesson on the dangers of unverified assumptions and the importance of cognitive analysis in contemporary joint operation planning.
Kiska is part of the Aleutian Archipelago, a chain of volcanic islands stretching from the Alaskan mainland to the far western edge of the Bering Sea. Barren, windswept, and shrouded in perpetual fog, the Aleutians embody some of the harshest weather and most desolate terrain on the North American continent. Despite this inhospitable environment, the Japanese were intensely interested in the Aleutians due to the unique geography. The islands form a natural corridor between the Eastern and Western hemispheres. By occupying key strategic locations along the Aleutians, the Japanese hoped to control and defend the northern perimeter of their expanding Pacific empire.4
The Japanese seized Kiska on June 7, 1942. The attack was part of a north Pacific diversion for the Midway campaign orchestrated by Admiral Isoroku Yamamoto, commander in chief of the Imperial Japanese Navy (IJN) Combined Fleet.5 Yamamoto’s plan included a carrier-based air assault of American naval facilities at Dutch Harbor, Alaska, and occupation of Kiska and Attu, the westernmost islands in the Aleutian chain. The Kiska occupation force consisted of approximately 7,800 marines of the IJN Special Naval Landing Forces under the command of Rear Admiral Monzo Akiyama. Over 500 civilian laborers were also brought to the island to construct harbor facilities on Kiska’s natural deep-water bay and an elaborate system of caves and tunnels throughout the rocky high ground.6
Japanese possession of Kiska and Attu dealt a significant psychological blow to the American war effort. No enemy force had occupied North American territory since the War of 1812, and news of Japanese presence in the Aleutians threatened both the confidence and morale of the American public. Defense of the Aleutians was vested in the Alaska Defense Command (ADC), a skeletal force of 24,000 under the command of Major General Simon Bolivar Buckner, Jr. The command was a component of the Army’s Western Defense Command, established in 1941 to coordinate defense of the entire Pacific Coast region. In response to the Japanese foray into the Aleutians, the Joint Chiefs of Staff began a rapid buildup of U.S. forces in the region. By the fall of 1942, ADC had swelled to over 94,000 personnel.7
Seapower in the region was represented by the U.S. Navy’s North Pacific Task Force. Admiral Chester Nimitz, commander of the United States Pacific Fleet, established the North Pacific Force in May 1942 when Navy cryptographers first uncovered the Japanese plan to attack Midway and Dutch Harbor.8 To command the North Pacific fleet, Nimitz selected Rear Admiral Robert A. Theobald, a 34-year veteran of naval surface warfare operations. Since Japanese naval operations were considered the principal threat in the Aleutians, the Navy was designated the Service of paramount interest by the Joint Chiefs. Therefore, Theobald, as commander of the North Pacific Fleet, was given command authority over all Army and Navy forces in the region.9
In sending Theobald to the Aleutians, Nimitz unwittingly touched off a powder keg. The cerebral and cautious Theobald stood in stark contrast to the impatient and action-oriented Buckner. The two quarreled incessantly about the timetable for offensive operations and the disposition of air assets in the region. Buckner also complained of Theobald’s propensity to withhold intelligence from his Army counterparts, an assertion that Theobald justified based on his concern for operational security.10 Nimitz was aware of the contentious relationship that developed between Theobald and Buckner and its potential to be detrimental to the joint operations needed to oust the Japanese from the Aleutians. In December 1942, Nimitz replaced his reticent joint force commander (JFC) with Rear Admiral Thomas C. Kinkaid, who had recently served with distinction at the Battle of the Coral Sea and was reputed to be the kind of aggressive and decisive leader Nimitz required in the North Pacific.11
Kinkaid’s first major decision upon reaching the Aleutians was to establish an immediate naval blockade to wall off Kiska and Attu from Japanese shipping, an act of aggression much appreciated by Buckner.12 American B-24 bombers had already been assailing Kiska’s harbor since September 1942. The sea blockade only added to Japan’s logistical challenge of provisioning and sustaining its forces. By March 1943, the only supplies reaching Kiska and Attu on a consistent basis were those brought in by submarine.13
Of the two islands, Kiska was more significant from a strategic perspective. Kiska had a fully developed harbor, an operational airfield, and a substantially larger garrison. Despite Attu’s secondary importance, Kinkaid and Buckner agreed to repatriate the far western island first. Attu was lightly defended, and seizing it first would put U.S. forces astride the Japanese line of communications and erect a further barrier to supply and reinforcement of Kiska.14 On April 1, the Joint Chiefs approved Kinkaid’s petition to assault Attu. The operation, designated Landcrab, was scheduled for May 10, 1943.
Attu is approximately 35 miles long and 15 miles wide. Its snow-capped mountain peaks tower 3,000 feet above sea level. Steep, ice-covered slopes extend from the high ground down to a treeless plain of arctic tundra. The Japanese occupation force was comprised of a single Imperial Japanese Army infantry battalion under the command of Colonel Yasuyo Yamasaki.15 The Japanese spent the majority of their time on Attu constructing an airfield along the northeast shore of the island.
Execution of Landcrab was assigned to the Army’s 7th Division under the command of Major General Albert E. Brown. The American plan was to make simultaneous landings on the northern and easternmost shores of Attu, then push inland in perpendicular thrusts to trap the Japanese on the northeast corner of the island.16 The plan appeared simple given the occupier’s isolation and total lack of fire support, but the operation quickly ran into difficulties due to weather, the terrain, and a very shrewd Japanese defensive strategy.
American forces expected an intense coastal defense by the Japanese. What they found instead were abandoned shores as the occupiers pulled back from the coast to await the invasion force in the higher rocky terrain.17 The unopposed landing was welcome news to American troops already dealing with churning seas and 25-degree temperatures, but it did not bode well for an advance to the island interior, which now faced murderous mortar and machinegun fire from the higher ridges. The Japanese deployed their forces in small groups of sniper and mortar teams, which used the island’s natural network of caves, crevices, and ridgelines for concealment and protection. Naval and artillery bombardment were ineffective due to the thick fog. The fog also provided an ideal backdrop for Japanese snipers who kept watch on the few accessible slopes to the upper elevations and cut down U.S. infantry as they appeared above the fog line.18 Lack of positive news from the front coupled with Brown’s continuous call for reinforcements convinced Kinkaid that Operation Landcrab was bogged down. After consulting with Buckner on May 16, Kinkaid replaced Brown with Major General Eugene M. Landrum.19
The Japanese tenaciously defended every ridge and stronghold on Attu, but the numbers and elements were against them. As fresh American troops and supplies flowed freely through the open beachhead, the Japanese continued to expend their resources in a futile battle of attrition. By May 28, the Japanese situation had grown critical. Food, ammunition, and medical supplies were scarce. In desperation, Yamasaki prepared a bold plan. He would use his entire force to break through the frontlines and capture an artillery battery and supply depot at the crest of a prominent hill in the American rear area. With artillery, supplies, and strategic high ground in Japanese hands, Yamasaki hoped to hold the position until reinforcements arrived by sea.20 The audacious Japanese plan almost succeeded.
In the early morning hours of May 29, every Japanese soldier who was still able to walk set off on a silent trek toward the American frontlines. The Japanese quickly overpowered three sentry outposts and began a half-mile ascent toward the supply depot at the top of the hill. The position was practically undefended except for a battalion of U.S. Army combat engineers who somehow managed to beat back the attackers in a frenzied hand-to-hand melee.21 The engineers pushed the exhausted Japanese back to the base of the hill. Several of the Japanese made their way back to the caves and crevices of the high ground where they were eventually cornered and eliminated by American search teams. Most simply clutched a hand grenade to their chest and scattered themselves across the Aleutian tundra.
As the fog lifted, the morning sun revealed a grisly sight. Over 500 Japanese bodies lay horribly mutilated on the valley floor. Several hundred more bodies, both American and Japanese, were littered across the crest and down the long slope of the hill.22 The Japanese had virtually fought to the death. Only 29 wounded Japanese soldiers remained alive from the 2,650 that once inhabited the island. The American casualty rate was stunning. Of the approximately 16,000 troops engaged on Attu, the invasion force suffered 3,829 casualties, including 549 killed in action.23 To Kinkaid and the Joint Chiefs, the bloody victory on Attu was an unimpeachable portent of things to come.24
With Attu now under U.S. Army control, the Joint Chiefs directed their attention to Kiska. American intelligence estimated Japanese troop strength on Kiska at approximately 10,000, and aerial reconnaissance thoroughly documented a labyrinth of hardened tunnels and bunkers throughout the high ground.25With Attu still fresh in his mind, Kinkaid, who had been promoted to vice admiral after Landcrab, was determined to allocate sufficient resources for the greater challenge of Kiska. Command of the attack force was vested in Rear Admiral Francis Rockwell, an amphibious operations specialist who had served as principal planner for the Attu invasion. Major General Charles Corlett was to command the landing force, an assemblage that ballooned to over 34,000 with the addition of the 5,300-strong 13th Royal Canadian Infantry Brigade.26
During the month of July, Eleventh Air Force dropped 424 tons of ordnance on Kiska, while an offshore screen of U.S. Navy cruisers and destroyers lobbed an additional 330 tons of shell onto the island.27 Air reconnaissance operations were relentless, collecting intelligence on Kiska’s occupiers at every opportunity allowed by the notorious Aleutian fog. As the assault preparations extended into August, the combined landing force began to assemble on Adak Island, 200 miles east of Kiska.
Starting in late July, however, air photo interpreters began to note curious observations. Routine activities on Kiska appeared to diminish significantly, and almost no movement could be detected within the harbor. Bomb-damaged buildings and craters on Kiska’s airfield were left unrepaired, a suspicious breach of protocol for the industrious Japanese. Aircrews also reported greatly diminished antiaircraft fire. On July 28, radio signals from Kiska ceased entirely.28 To many intelligence analysts, the mounting evidence suggested that the Japanese had somehow slipped through the Allied naval blockade and evacuated Kiska. Kinkaid did not agree. Influenced strongly by Japanese tactics on Attu, he argued that the enemy had simply taken to the upper elevations. Staff suggestions for further aerial reconnaissance and an advance scouting party were discounted as risky and unnecessary.29 On July 30, Kinkaid requested and received final approval from Nimitz to execute Operation Cottage. D-day was set for August 15, H-hour at 0630.
The morning of August 15 was unusually calm and clear in the western Aleutians, but the brief respite from fog and gale force winds did not insulate the assault force from adversity. An inaccurate tidal forecast caused several tank landing ships to run aground the submerged web of volcanic rock off the Kiska beachhead. The stationary vessels triggered a traffic jam, as countless landing craft backed up and bobbed unproductively in the littoral.30 The landing was unopposed as predicted, but to the infantry veterans who witnessed the carnage on Attu, the lack of contact with enemy forces simply meant that the Japanese were calmly waiting in prepared positions on higher ground.31
As the landing craft slowly wove their way onto the beach, a dense fog began to settle over the island, bringing with it a cold, steady rain. There was no shelter for the exposed landing force. The icy blanket of fog soon reduced visibility to near zero. As night fell, disoriented troops scratched shallow foxholes in the rocky tundra in which to await daylight and some semblance of order. Sleep was impossible. Sporadic firing could be heard in all directions, and the eerie glow of tracer bullets tearing through fog only added to the confusion. Voices trying to organize and coordinate were muffled and swept away by the wind.32
Daylight eased the tension, but the fog, rain, and cold wind remained. As the infantry began their climb into the high ground, artillery fire roared out of the mist behind them. Support fire from warships continued to whistle overhead and explode in the distance. Rumors of casualties, firefights, and elusive Japanese snipers circulated with abandon.33 By mid-afternoon, advance elements of infantry began to reach the lower echelons of Japanese fortifications. Now, new reports of abandoned bunkers and caches of destroyed weapons seemed to contradict the earlier rumors. As more deserted tunnels and dugouts were explored, the embarrassing truth became evident. The combined invasion force had seized an uninhabited island.
The uneasy silence that settled across the island did not lure the infantry into a false sense of security. The rumors of casualties were true. Lives had been lost through friendly fire, vehicle accidents, land mines, and booby traps. On the morning of August 18, the Navy destroyer Amner Read struck a mine in Kiska harbor, killing 70 sailors and wounding 47. All told, the Allied forces suffered 92 fatalities during Operation Cottagewith a further 221 wounded.34
Although the assault of a deserted island was an embarrassment, and Kinkaid was roundly criticized in the American media, the operation did pay dividends in ways not apparent to Kinkaid’s detractors. Amphibious warfare techniques were refined after the Kiska landing, and Kinkaid’s decision to bypass and isolate heavily defended Kiska by first seizing Attu set a strategic precedent for the successful island-hopping campaign of 1943–1945.35 Moreover, Japan’s foothold in the Aleutians was gone.
The final mysteries of Kiska were not solved until after the war when interrogation of Japanese officials exposed details of the Japanese strategic retreat. The interviews revealed that the brutal slugfest on Attu had made as deep an impression on the Japanese Imperial Command as it had on Kinkaid and the Joint Chiefs. The continued Allied naval blockade of Kiska, along with relentless bombing by the Eleventh Air Force, convinced the Japanese that a second Allied assault to repatriate Kiska was imminent.36 The decision to evacuate the Kiska garrison was not taken lightly. Some voices within the Imperial High Command held that a withdrawal from Kiska would dishonor the dead of Attu and that the soldiers of Kiska should be left to fight to an honorable death as well.37 But even the most aggressive Japanese commanders realized that Japan’s hold on Kiska was pointless, and manpower was badly needed elsewhere in the Pacific. On May 19, the Imperial High Command reluctantly issued orders to abandon Kiska.38
The original Japanese plan was to gradually withdraw the Kiska garrison by submarine, but this scheme was aborted in late June after three submarines assigned to the operation were detected and sunk by Allied destroyers.39 It was then decided to evacuate the force using surface vessels as transports, leaving only a small rear guard to destroy hard assets and plant booby traps. On the evening of July 28, a small task force of cruisers and destroyers slipped through the Allied naval blockade under the cover of fog and extracted over 5,000 Japanese troops in less than an hour.40 The rear guard, which accounted for the sporadic antiaircraft fire in the days preceding the assault, was later evacuated by submarine. In the end, the Japanese evacuation of Kiska was a daring and brilliant success.
Operation Cottage was based on two key assumptions: the Japanese occupied Kiska, and the Japanese would not retreat from Kiska. That the Allied staff might have had an unrealistic impression of Japanese resilience and fortitude in August 1943 is understandable given the context of prior events in the Pacific. The speed and ease with which the Japanese seized Malaya, Singapore, and the island of Luzon in the Philippines stunned the Allies. Japan’s samurai heritage and code of ethics known as bushido fueled a stereotype of a warrior culture steeped in obedience, discipline, and staunch revulsion to surrender. The intensity and savagery of the fighting on Attu only served to reinforce this image. Even the intelligence—the suspicious absence of observable activity, the unrepaired bomb damage, and the lack of signals intelligence—could all be attributed to a cunning enemy who had taken to the hills to await battle in prepared fortifications.
Every operation begins with assumptions. A prime objective of mission analysis is to convert basic assumptions into known fact.41 An assumption should never be accepted as fact based simply on perception or superficial evidence, and as Operation Cottage demonstrates, the logic behind invalid assumptions can sometimes be extremely compelling. Fortunately, contemporary operation planners have systematic doctrinal guidance to avoid the pitfalls of perceptual bias and distinguish assumption from fact. The JOPP is a structured decisionmaking tool used to examine mission objectives and plan operations. JOPP is supported by Joint Intelligence Preparation of the Operational Environment (JIPOE), an analytical process used to determine an adversary’s strength, disposition, and potential courses of action (COAs). Both the JOPP and JIPOE instill structured analytical techniques to challenge assumptions, identify mindsets, and stimulate outside-the-box thinking.
One of the primary techniques employed throughout the JOPP is red team analysis. Red teams comprise trained experts from the command staff who independently review plans from a contrarian perspective in order to identify alternative hypotheses and challenge basic assumptions.42 Often, the same evidence that supports an initial reflex assumption may be consistent with several different hypotheses. Red team analysis helps the planning staff validate its intuitive assumptions by asking why the assumptionmust be true, and whether the assumption will remain true under all conditions.43 Assumptions that cannot be validated through mission and red team analysis are captured as an information requirement. The J2 has overall staff responsibility for consolidating information requirements nominated through the JOPP and for recommending to the commander their approval and relative priority.44 If a key decision must be made based upon an assumption, the information needed to validate that assumption is designated a Commander’s Critical Information Requirement.45
Contrarian assessment and cognitive analysis are important components of JIPOE as well. The primary purpose of JIPOE is to support the JFC decisionmaking and planning process by providing a holistic view of the operational environment and adversary.46 JIPOE, which is codified in JP 2-01.3, Joint Intelligence Preparation of the Operational Environment, consists of four basic steps: a description of the operational environment, description of the impact of the operational environment, evaluation of the adversary, and finally, determination of the adversary’s likely COAs. The JIPOE process provides situational awareness and assumptions regarding the operational environment and the adversary and lays the foundation for an intelligence collection strategy to resolve the unknown. Intelligence collection and analysis are continuous throughout the JIPOE process. When new intelligence confirms or repudiates an assumption, any decision that was based on that assumption must be reexamined for validity.47
Some assumptions are unavoidable. There will always be gaps in knowledge and information shortfalls, particularly in view of adversary denial and deception efforts. Contingency planning, no matter how thorough, will always include assumptions that cannot be resolved until the actual crisis unfolds. In these instances, the command staff should formulate reasonable assumptions based on historical context and the best information available. Mission planners must ensure that all assumptions are clearly identified and captured as a risk for the commander’s consideration.48
Perceptions about the Japanese adversary on Kiska were deeply ingrained in Kinkaid and his command staff, but a reexamination of the assumptions leading to OperationCottage illustrates how a thoroughly executed contrarian analysis might have revealed evidence to consider an evacuation of the island among the more likely COAs to be employed by the Japanese. The rapid string of victories that did so much to typecast Japanese tenacity in the early months of the war also showed a remarkable capacity for strategic planning and military pragmatism. This practicality was demonstrated just 6 months prior to Operation Cottage when the Japanese evacuated Guadalcanal rather than fight to the end against an overwhelming Allied invasion force. Just as the prior Japanese exodus from Guadalcanal supported a probable evacuation of Kiska, so too did the intelligence. But to the planners of Operation Cottage, the variety of intelligence collected on Kiska only served to confirm their firmly held beliefs. Had the key baseline assumptions of Japanese presence and resilience been called into doubt, the supporting intelligence might have been given more credence and directed events to a decidedly different outcome.
JOPP and JIPOE provide mission planners with a logical, structured framework to identify, analyze, and assess perceived contradictions in the operational environment. Without these cognitive analysis resources, commanders have little recourse but to execute plans based solely on supposed knowledge of adversary intentions, a scenario that aptly describes Operation Cottage. Disproportionally influenced by popular stereotypes and Japanese tactics on Attu, Allied decisionmakers misread and misunderstood Japanese intentions on Kiska, facilitating a needless loss of blood and treasure.
Two tense and nerve-shattering days after landing on the shores of Kiska, exhausted Allied soldiers pulled themselves out of water-filled foxholes and surveyed their desolate surroundings. Among the artifacts left behind by the retreating Japanese were one stray dog, several primitive booby traps, and thousands of propaganda leaflets that had been air dropped by U.S. Army Intelligence. The leaflets informed the Japanese that their situation was hopeless and urged the immediate surrender of Kiska.49 It did not occur to Kinkaid and his senior staff that the propaganda’s intended audience would actually heed the advice. JFQ