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The Attack on Pearl Harbour

Part 1

Summarised from Wikipedia, the free encyclopedia

The attack on Pearl Harbour was a surprise military strike by the Imperial Japanese Navy Air Service upon the United States of America. The United States was a neutral country at the time and the Imperial Japanese Navy Air Service launched an attack against the naval base at Pearl Harbour in Honolulu, a Territory of Hawaii, just before eight o’clock on Sunday morning, the 7th of December, 1941. The attack led to the formal entry of the United States into World War II on the next day. The Japanese military leadership referred to the attack as the Hawaii Operation and Operation AI. During its planning, they also referred to it as Operation Z.

Japan intended the attack as a preventive action to keep the United States Pacific Fleet from interfering with its planned military actions in Southeast Asia against the overseas territories of the United Kingdom, the Netherlands, and the United States. Over the course of seven hours, there were coordinated Japanese attacks on the Philippines, Guam and Wake Island all held by the United States and on the British Empire in Malaya, Singapore, and Hong Kong.

The attack started at 7:48 a.m. Hawaiian Time. The base was attacked by 353 Imperial Japanese aircraft, launched from six aircraft carriers in two waves including fighter planes, dive bombers, and torpedo bombers. All eight United States Navy battleships were damaged, and four of them were sunk. All of the battleships except for the USS Arizona were later raised, and six of the battleships were returned to service and went on to fight in the war. The Japanese also sank or damaged three cruisers, three destroyers, an anti-aircraft training ship, and one minelayer. 188 United States aircraft were destroyed, 2,403 Americans were killed, and 1,178 Americans were wounded. Important base installations such as the power station, the dry dock, the shipyard, the maintenance facilities, the fuel and torpedo storage facilities, as well as the submarine piers and the headquarters building (also the home of the intelligence section) were not attacked. Japanese losses were light: 29 aircraft and five midget submarines were lost, and 64 servicemen were killed. The commanding officer of one of the submarines was captured.

Japan announced a declaration of war on the United States later that day (that is, on the 8th of December in Tokyo), but the declaration was not delivered until the following day. The following day, the 8th of December, Congress declared war on Japan. On the 11th of December, Germany and Italy each declared war on the United States, which responded with a declaration of war against Germany and Italy.

There were numerous historical precedents for the unannounced military action by Japan, but the lack of any formal warning, particularly while peace negotiations were still apparently ongoing, led President Franklin D. Roosevelt to proclaim the 7th of December, 1941, “a date which will live in infamy”. Because the attack happened without a declaration of war and without explicit warning, the attack on Pearl Harbour was later judged in the Tokyo Trials to be a war crime.  

Background to the conflict

Diplomatic background

War between Japan and the United States had been a possibility that each nation had been aware of, and planned for, since the 1920s. The relationship between the two countries was cordial enough that they remained trading partners. Tensions did not seriously grow until Japan’s invasion of Manchuria in 1931. Over the next decade, Japan expanded into China, leading to the Second Sino-Japanese War in 1937. Japan spent considerable effort trying to isolate China, and endeavoured to secure enough independent resources to achieve victory on the mainland. The “Southern Operation” was designed to assist these efforts.

Starting in December 1937, events such as the Japanese attack on the USS Panay, the Allison incident, and the Nanking Massacre swung Western public opinion sharply against Japan. Fearing Japanese expansion, the United States, the United Kingdom, and France assisted China with loans for war supply contracts.

In 1940, Japan invaded French Indochina, attempting to prevent the flow of supplies reaching China. The United States halted shipments of airplanes, parts, machine tools, and aviation gasoline to Japan. Japan considered this to be an unfriendly act. However, the United States did not stop oil exports, partly because of the prevailing point of view in Washington that such an action was likely to be considered as extreme provocation due to Japanese dependence on American oil.

In mid-1940, President Franklin D. Roosevelt moved the Pacific Fleet from San Diego to Hawaii. He also ordered a military build-up in the Philippines, taking both actions in the hope of discouraging Japanese aggression in the Far East. Because the Japanese high command was mistakenly certain that any attack on the United Kingdom’s Southeast Asian colonies, including Singapore, would bring the United States into the war, a devastating preventive strike appeared to be the only way to prevent American naval interference. An invasion of the Philippines was also considered necessary by Japanese war planners. War Plan Orange, a plan prepared by the United States, had envisaged defending the Philippines with an elite force of 40,000 men; this option was never implemented due to opposition from Douglas MacArthur, who felt that he would need a force ten times that size. By 1941, United States planners expected to abandon the Philippines at the outbreak of war. Late that year, the commander of the Asiatic Fleet was given orders to abandon the Philippines.

The United States finally ceased oil exports to Japan in July, 1941, following the seizure of French Indochina after the Fall of France, in part because of new American restrictions on domestic oil consumption. Because of this decision, Japan proceeded with plans to take the oil-rich Dutch East Indies. On the 17th of August, Roosevelt warned Japan that America was prepared to take appropriate steps if “neighbouring countries” were attacked. The Japanese were faced with a dilemma: either withdraw from China and lose face, or seize new sources of raw materials in the resource-rich European colonies of Southeast Asia.

Part 2

Japan and the United States engaged in negotiations during 1941 in an attempt to improve relations. In the course of these negotiations, Japan offered to withdraw from most of China and Indochina after making peace with the Nationalist government. It also proposed to adopt an independent interpretation of the Tripartite Pact and to refrain from trade discrimination, provided all of the other nations reciprocated. Washington rejected these proposals. The Japanese Prime Minister, Konoye, then offered to meet with President Roosevelt, but Roosevelt insisted on reaching an agreement before any meeting. The United States ambassador to Japan repeatedly urged Roosevelt to agree to the meeting, warning that it was the only way to preserve the conciliatory Konoye government and peace in the Pacific. However, the ambassador’s recommendation was not acted upon. The Konoye government collapsed the following month, and the Japanese military then rejected a withdrawal of all troops from China.

Japan’s final proposal, delivered on the 20th of November, offered to withdraw from southern Indochina and to refrain from attacks in Southeast Asia, so long as the United States, the United Kingdom, and the Netherlands supplied one million gallons of aviation fuel, lifted their sanctions against Japan, and ceased aid to China. The American counter-proposal of the 26th of November (the 27th of November in Japan), commonly known as the “Hull Note”, required Japan to completely evacuate China without conditions and conclude non-aggression pacts with the Pacific powers. On the 26th of November in Japan, the day before the delivery of the “Hull Note”, the Japanese task force left port for Pearl Harbour.

The Japanese intended the attack as a preventive action to keep the United States Pacific Fleet from interfering with its planned military actions in Southeast Asia against the overseas territories of the United Kingdom, the Netherlands, and the United States. Over the course of seven hours, there were coordinated Japanese attacks on the Philippines, Guam and Wake Island held by the United States and on the British Empire in Malaya, Singapore, and Hong Kong. Additionally, from the Japanese viewpoint, it was seen as a preventive strike “before the oil gauge ran empty”.

Military planning

Preliminary planning for an attack on Pearl Harbour to protect the move into the “Southern Resource Area” (the Japanese term for the Dutch East Indies and Southeast Asia generally) had begun very early in 1941 under the supervision of Admiral Yamamoto, who was then commanding Japan’s Combined Fleet. He was given approval from the Imperial Japanese Navy General Staff for the formal planning and training of an attack only after a great deal of arguing with Naval Headquarters, including threating to resign his command. Full-scale planning was underway by early spring 1941. The planners intensively studied the 1940 British air attack on the Italian fleet at Taranto.

Over the next several months, pilots were trained, equipment was adapted, and intelligence was collected. Despite these preparations, Emperor Hirohito did not approve the attack plan until the 5th of November, after the third of four Imperial Conferences called to consider the matter. Final authorization was not given by the emperor until the 1st of December, after a majority of Japanese leaders advised him that the “Hull Note” would “destroy the fruits of the China incident, endanger Manchukuo and undermine Japanese control of Korea”.

By late 1941, many observers believed that hostilities between the United States and Japan were imminent. A Gallup poll just before the attack on Pearl Harbour found that 52 percent of Americans expected war with Japan, 27 percent did not, and 21 percent had no opinion. While United States Pacific bases and facilities had been placed on alert on many occasions, United States officials doubted that Pearl Harbour would be the first target; instead, they expected the Philippines would be attacked first. This presumption was due to the threat posed to sea lanes by the air bases located throughout the Philippines and the naval base at Manila, as well as the threat to the shipment of supplies to Japan from territories to the south of the Philippines. The Americans also incorrectly believed that Japan was not capable of mounting more than one major naval operation at a time.


The Japanese attack had several major aims. First, it intended to destroy important American fleet units, thereby preventing the Pacific Fleet from interfering with the Japanese conquest of the Dutch East Indies and Malaya and to enable Japan to conquer Southeast Asia without interference. Second, Japan hoped to buy time to consolidate its position and to increase its naval strength before shipbuilding authorized by the United States Two-Ocean Navy Act in 1940 eliminated any chance of victory. Third, in order to deliver a blow to the ability of the United States to mobilize its forces in the Pacific, battleships were chosen as the main targets as they were the most prestigious ships of any navy at the time. Finally, Japan hoped that the attack would undermine American morale so much that the United States Government would seek a compromise peace with Japan and drop its demands that were contrary to Japanese interests.

Striking the Pacific Fleet at anchor in Pearl Harbour carried two distinct disadvantages: firstly, the targeted ships would be in very shallow water, so it would be relatively easy to salvage and possibly repair them; and, secondly, most of the crews would survive the attack, since many would be on shore leave or would be rescued from the harbour. A further important disadvantage was the absence from Pearl Harbour of all three of the United States Pacific Fleet’s aircraft carriers (the USS Enterprise, the USS Lexington, and the USS Saratoga). This was known to the Japanese. The Imperial Japanese Navy top command embraced Admiral Mahan’s “decisive battle” doctrine, especially that of destroying the maximum number of battleships. Despite these concerns, Yamamoto decided to press ahead.

Japanese confidence in their ability to achieve a short, victorious war also meant other targets in the harbour, especially the navy yard, the oil tank farms, and the submarine base, were ignored, because they thought that the war would be over before the influence of these facilities would be felt.

Approach and attack

On the 26th of November, 1941, a Japanese task force of six aircraft carriers left the Kuril Islands in the north of Japan to travel to a position northwest of Hawaii, intending to launch its 408 aircraft to attack Pearl Harbour. 360 aircraft would be used for the two attack waves and 48 aircraft would be on defensive combat air patrol, including nine fighters from the first wave.

The first wave was to be the primary attack, while the second wave was to attack the carriers as its first objective and the cruisers as its second objective, and finally the battleships as its third objective. The first wave carried most of the weapons necessary to attack the large warships, mainly specially adapted Type 91 aerial torpedoes which were designed with an anti-roll mechanism and a rudder extension that let them operate in shallow water. The aircrews were ordered to select the highest value targets (battleships and aircraft carriers) or, if these were not present, any other high value ships (cruisers and destroyers). The first wave dive bombers were to attack ground targets. The fighter planes were ordered to bombard and destroy as many parked aircraft as possible to ensure they did not get into the air to intercept the bombers, especially in the first wave. When their fuel got low, the fighter planes were to refuel at the aircraft carriers and return to combat. The fighter planes were to serve combat air patrol duties where needed, especially over the United States airfields.

Before the attack commenced, the Imperial Japanese Navy launched reconnaissance floatplanes from two cruisers with orders to report on United States fleet composition and location. The reconnaissance aircraft flights risked alerting the United States and were not necessary. The United States fleet composition and information about the preparedness of Pearl Harbour were already known due to reports from a Japanese spy.


Five fleet submarines each embarked a Type A midget submarine for transport to the waters off Oahu. The five submarines left Japan on the 25th of November, 1941. On the 6th of December, they came within 10 nautical miles (which is 19 kilometres or 12 miles) of the mouth of Pearl Harbour and launched their midget submarines at about 01:00 local time on the 7th of December. At 03:42 Hawaiian Time, the minesweeper Condor spotted a midget submarine periscope southwest of the Pearl Harbour entrance buoy and alerted the destroyer Ward. The midget submarine may have entered Pearl Harbour. However, the Ward sank another midget submarine at 06:37 in the first American shots in the Pacific Theatre. A midget submarine on the north side of Ford Island missed the Seaplane Tender Curtiss with her first torpedo and missed the attacking destroyer Monaghan with her other torpedo before being sunk by the Monaghan at 08:43.

A third midget submarine grounded twice, once outside the harbour entrance and once again on the east side of Oahu, where it was captured on the 8th of December. A submarine officer became the first Japanese prisoner of war when he swam ashore and was captured by an Hawaii National Guard Corporal. A fourth midget submarine had been damaged by a depth charge attack and was abandoned by its crew before it could fire its torpedoes. Japanese forces received a radio message from a midget submarine at 00:41 on the 8th of December claiming damage to one or more large warships inside Pearl Harbour.

Part 3

In 1992, 2000, and 2001, submersibles operated by the Hawaii Undersea Research Laboratory found the wreck of the fifth midget submarine lying in three parts outside Pearl Harbour. The wreck was in the debris field where a lot of surplus United States equipment was dumped after the war, including vehicles and landing craft. Both of its torpedoes were missing. This correlates with reports of two torpedoes fired at the light cruiser St. Louis at 10:04 at the entrance of Pearl Harbour, and a possible torpedo fired at the destroyer, Helm, at 08:21.

Japanese declaration of war

The attack took place before any formal declaration of war was made by Japan, but this was not Admiral Yamamoto’s intention. He originally stipulated that the attack should not commence until thirty minutes after Japan had informed the United States that peace negotiations were at an end. However, the attack began before the notice could be delivered. Tokyo transmitted the five thousand word notification (commonly called the “Fourteen Part Message”) in two blocks to the Japanese Embassy in Washington. It took the Japanese ambassador too long to transcribe the message and he could not deliver it on schedule. It was not presented until more than an hour after the attack began. In fact, United States code breakers had already deciphered and translated most of the message hours before the ambassador was scheduled to deliver it. The final part is sometimes described as a declaration of war. While this final part was viewed by a number of senior United States Government and military officials as a very strong indicator that negotiations were likely to be terminated and that war might break out at any moment, it neither declared war nor severed diplomatic relations. A declaration of war was printed on the front pages of the evening editions of Japan’s newspapers on the 8th of December (late on the 7th of December in the United States), but the declaration of war was not delivered to the United States Government until the day after the attack.

For decades, conventional wisdom held that Japan attacked without first formally breaking diplomatic relations only because of accidents and bumbling that delayed the delivery of a document hinting at war to Washington. In 1999, however, Takeo Iguchi, a professor of law and international relations at the International Christian University in Tokyo, discovered documents that pointed to a vigorous debate inside the Japanese Government over how, and indeed whether, to notify Washington of Japan’s intention to break off negotiations and start a war, including an entry on the 7th of December in the war diary saying, “our deceptive diplomacy is steadily proceeding toward success”. Commenting on this, Professor Iguchi writes, “the diary shows that the army and the navy did not want to give any proper declaration of war, or indeed prior notice even of the termination of negotiations … and they clearly prevailed”.

In any event, even if the Japanese had decoded and delivered the “Fourteen Part Message” before the beginning of the attack, it would not have constituted either a formal break of diplomatic relations or a declaration of war. The final two paragraphs of the message effectively reads:

“Thus the hope of the Japanese Government to improve Japanese-American relations and to preserve and promote peace in the Pacific through cooperation with the American Government has finally been lost.

The Japanese Government regrets to notify the American Government that in view of the attitude of the American Government it considers that it is impossible to reach an agreement through further negotiations.”

First wave composition

The first attack wave of 183 planes was launched north of Oahu. Six planes failed to launch due to technical difficulties. The first attack included three groups of planes:

•  The First Group targeted battleships and aircraft carriers and consisted of 49 bombers in four sections armed with 800-kilogram armour-piercing bombs and 40 bombers armed with Type 91 torpedoes also in four sections. One bomber failed to launch.

•  The Second Group targeted Ford Island and Wheeler Field and consisted of 51 dive bombers armed with 249-kilogram general-purpose bombs. Three dive bombers failed to launch.

•  The Third Group targeted aircraft at Ford Island, Hickam Field, Wheeler Field, Barber’s Point, and Kaneohe and consisted of 43 Mitsubishi fighter planes for air control and bombarding. Two fighter planes failed to launch.

As the first wave approached Oahu, it was detected by the United States Army radar at Opana Point near the island’s northern tip. This post had been in training mode for months, but was not yet operational. The operators reported a target, but the newly assigned officer at the thinly manned Intercept Centre assumed it was the scheduled arrival of six B-17 Flying Fortress bombers from California. The Japanese planes were approaching from a direction very close to the bombers (a difference of only a few degrees), and while the operators had never seen a formation as large on radar, they neglected to tell the officer how large it was. For security reasons, the officer could not tell the operators that six B-17s were due, even though it was widely known.

As the first wave planes approached Oahu, they encountered and shot down several United States aircraft. At least one of these aircraft radioed a somewhat incoherent warning. Other warnings from ships off the harbour entrance were still being processed or awaiting confirmation when the attacking planes began bombing and machine-gunning. Nevertheless, it is not clear that any warnings would have had much effect even if they had been interpreted correctly and in good time. The results the Japanese achieved in the Philippines were essentially the same as at Pearl Harbour, even though MacArthur had almost nine hours warning following the Japanese attack on Pearl Harbour.

The air portion of the attack began at 7:48 a.m. Hawaiian Time with the attack on Kaneohe. A total of 353 Japanese planes in two waves reached Oahu. Slow, vulnerable torpedo bombers led the first wave, exploiting the first moments of surprise to attack the most important ships present, namely the battleships, while dive bombers attacked United States air bases across Oahu, starting with the largest air base Hickam Field, and Wheeler Field, the main United States Army Air Forces fighter base. The 171 planes in the second wave attacked Bellows Field near Kaneohe occupied by the Army Air Forces and Ford Island. The only aerial opposition came from a handful of Curtiss P-36 Hawks, Curtiss P-40 Warhawks, and some Douglas Dauntless dive bombers from the Carrier Enterprise.

In the first wave attack, about eight of the forty-nine 800-kilogram armour-piercing bombs hit their intended battleship targets. At least two of those bombs broke up on impact, another detonated before penetrating an unarmoured deck, and one was a dud. Thirteen of the forty torpedoes hit battleships, and four torpedoes hit other ships. Men aboard the United States ships awoke to the sounds of alarms, bombs exploding, and gunfire, prompting bleary-eyed men to dress as they ran to battle stations. The famous message, “AIRRAID ON PEARL HARBOUR X THIS IS NO DRILL”, was sent from the headquarters of Patrol Wing Two, the first senior Hawaiian command to respond. The defenders were very unprepared. Ammunition lockers were locked, aircraft were parked wingtip to wingtip in the open to prevent sabotage, and guns were unmanned. None of the Navy’s naval guns and only a quarter of the Navy’s machine guns got into action. Only four of the 31 Army batteries got into action. Despite this low alert status, many American military personnel responded effectively during the attack. Aboard the Nevada, an officer commanded the ship’s anti-aircraft guns and was severely wounded, but he continued to be on post. While a lieutenant commander commanded the Nevada in the absence of the captain and got her under way until the ship was grounded at 9:10 a.m. One of the destroyers, theAylwin, got under way with only four officers aboard, none of them with more than a year’s sea duty; she operated at sea for 36 hours before her commanding officer managed to get back aboard. The captain of the West Virginia led his men until he was cut down by fragments from a bomb which hit the Tennessee, moored alongside.

Second wave composition

The second planned wave consisted of 171 planes: 54 bombers, 81 dive bombers, and 36 fighter planes. Four planes failed to launch because of technical difficulties. This wave and its targets also comprised three groups of planes:

•  The First Group consisted of 54 bombers armed with 249-kilogram and 60-kilogram general-purpose bombs. 27 bombers targeted the aircraft and hangars on Kaneohe, Ford Island, and Barber’s Point. 27 bombers targeted the hangars and aircraft on Hickam Field.

•  The Second Group targeted aircraft carriers and cruisers. 78 dive bombers armed with 249-kilogram general purpose bombs in four sections. Three bombers aborted.

•  The Third Group targeted the aircraft at Ford Island, Hickam Field, Wheeler Field, Barber’s Point, and Kaneohe. 35 Mitsubishi fighter planes were deployed for defence and bombarding. One plane aborted.

The second wave was divided into three groups. One group was tasked to attack Kaneohe, the other groups were tasked to attack Pearl Harbour itself. The separate sections arrived at the attack point almost simultaneously from several directions.

American casualties and damage

The attack was over, ninety minutes after it began. 2,008 sailors were killed and 710 others were wounded; 218 soldiers and airmen were killed and 364 were wounded; 109 marines were killed and 69 were wounded; finally 68 civilians were killed and 35 were wounded. In total, 2,403 Americans were killed and 1,143 Americans were wounded. Eighteen ships were sunk or run aground, including five battleships. All of the Americans killed or wounded during the attack were legally non-combatants as there was no state of war when the attack occurred.

Part 4

Of the American fatalities, nearly half were due to the explosion of the Arizona’s forward magazine after it was hit by a modified 16 inch shell. Among the notable civilian casualties were nine Honolulu Fire Department firefighters who responded to Hickam Field during the bombing in Honolulu, becoming in history the only fire department members on American soil to be attacked by a foreign power.

Already damaged by a torpedo and on fire, the Nevada attempted to exit the harbour. She was targeted by many Japanese bombers as she got under way and sustained more hits from 113-kilogram bombs, which started further fires. She was deliberately beached to avoid blocking the harbour entrance. The California was hit by two bombs and two torpedoes. The crew might have kept her afloat, but were ordered to abandon ship just as they were raising power for the pumps. Burning oil from the Arizona and the West Virginia drifted down on her, and probably made the situation look worse than it was. The disarmed target ship, the Utah, was holed twice by torpedoes. The West Virginia was hit by seven torpedoes, the seventh tearing away her rudder. The Oklahoma was hit by four torpedoes, the last two above her belt armour, which caused her to capsize. The Maryland was hit by two of the modified 16 inch shells, but neither caused serious damage.

Although the Japanese concentrated on battleships, the largest vessels present, they did not ignore other targets. The light cruiser Helena was torpedoed, and the concussion from the blast capsized the neighbouring minelayer, the Oglala. Two destroyers in the dry dock, the Cassin and the Downes, were destroyed when bombs penetrated their fuel bunkers. The leaking fuel caught fire. Flooding the dry dock in an effort to fight the fire made the burning oil rise, and both were burned out. The Cassin slipped from her keel blocks and rolled against the Downes. The light Cruiser Raleigh was holed by a torpedo. The light cruiser Honolulu was damaged, but remained in service. The Repair Vessel Vestal, moored alongside the Arizona, was heavily damaged and beached. The Seaplane Tender Curtiss was also damaged. The Destroyer Shaw was badly damaged when two bombs penetrated her forward magazine.

Of the 402 American aircraft in Hawaii, 188 were destroyed and 159 were damaged, 155 of them on the ground. Almost none were actually ready to take off to defend the base. Eight Army Air Force pilots managed to get airborne during the attack and six were credited with downing at least one Japanese aircraft during the attack. Of the 33 patrol bombers in Hawaii, 24 were destroyed, six were damaged beyond repair, and three on patrol at the time of the attack returned undamaged. In addition, friendly fire brought down some United States planes, including five from an inbound flight from the Enterprise.

At the time of the attack, nine civilian aircraft were flying in the vicinity of Pearl Harbour. Of these, three were shot down.

Japanese losses  

Fifty-five Japanese airmen and nine submariners were killed in the attack and one submariner was captured. Of Japan’s 414 available planes, 350 planes took part in the raid and 29 planes were lost. Nine planes were lost in the first wave (specifically, three fighters, one dive bomber and five torpedo bombers) and 20 planes were lost in the second wave (specifically, six fighters and 14 dive bombers) and another 74 planes were damaged by anti-aircraft fire from the ground.

Possible third wave

Several Japanese junior officers urged Admiral Nagumo to carry out a third strike to destroy as much as possible of Pearl Harbour’s fuel and torpedo storage, as well as the maintenance and dry dock facilities. The junior officers believed that three strikes were necessary to disable the base as much as possible. The captains of the other five carriers in the task force reported that they were willing and ready to carry out a third strike. Military historians have suggested the destruction of these shore facilities would have hampered the United States Pacific Fleet far more seriously than the loss of its battleships. If they had been wiped out, “serious [American] operations in the Pacific would have been postponed for more than a year”; according to Admiral Nimitz, who later became Commander-in-Chief of the Pacific Fleet, “it would have prolonged the war another two years.” Admiral Nagumo, however, decided to withdraw for several reasons:

•  American anti-aircraft performance had improved considerably during the second strike, and two thirds of Japan’s losses were incurred during the second wave.

•  Admiral Nagumo felt that if he launched a third strike then he would be risking three quarters of the Combined Fleet’s strength to wipe out the remaining targets (which included the facilities) while suffering higher aircraft losses.

•  The location of the American carriers remained unknown. In addition, the admiral was concerned his force was now within range of American land-based bombers. Admiral Nagumo was uncertain whether the United States had enough surviving planes on Hawaii to launch an attack against the Japanese carriers.

•  A third wave would have required substantial preparation and turnaround time. This would have meant that returning planes would have had to land at night. At the time, only the British Royal Navy had developed night carrier landing techniques, so this was a substantial risk.

•  The task force’s fuel situation made it difficult to remain in waters north of Pearl Harbour much longer, as they were at the very limit of logistical support. To do so risked running unacceptably low on fuel, perhaps even having to abandon destroyers on the journey back to Japan.

•  Admiral Nagumo believed that the second strike had essentially satisfied the main objective of his mission which was to neutralize the Pacific Fleet and he did not wish to risk further losses. Moreover, it was the policy of the Japanese Navy to prefer the conservation of strength over the total destruction of an enemy.

At a conference aboard his flagship the following morning, Yamamoto supported Admiral Nagumo’s withdrawal without launching a third wave. In retrospect, sparing the vital dockyards, the maintenance facilities, and the oil tank farm meant that the United States could respond relatively quickly to Japanese activities in the Pacific. Yamamoto later regretted the decision to withdraw and categorically stated that it had been a great mistake not to order a third strike.

Part 5

Ships lost or damaged

Twenty-one ships were damaged or lost in the attack. Except for three ships, all of them were repaired and returned to service.


•  The Battleship Arizona was hit by four armour-piercing bombs and exploded and was a total loss. 1,177 dead.

•  The Battleship Oklahoma was hit by five torpedoes and capsized and was a total loss. 429 dead.

•  The Battleship West Virginia was hit by two bombs and seven torpedoes and sunk. It returned to service in July, 1944. 106 dead.

•  The Battleship California was hit by two bombs and two torpedoes and sunk. It returned to service in January, 1944. 100 dead.

•  The Battleship Nevada was hit by six bombs and one torpedo and was beached. It returned to service in October, 1942. 60 dead.

•  The Battleship Pennsylvania was in the dry dock with the Cassin and the Downes and was hit by one bomb and debris from the Cassin. It remained in service. 9 dead.

•  The Battleship Tennessee was hit by two bombs. It returned to service in February, 1942. 5 dead.

•  The Battleship Maryland was hit by two bombs. It returned to service in February, 1942. 4 dead including a floatplane pilot who was shot down.

Ex-battleship used as a target and training ship

•  The Battleship Utah was hit by two torpedoes and capsized and was a total loss. 64 dead.


•  The Cruiser Helena was hit by one torpedo. It returned to service in January, 1942. 20 dead.

•  The Cruiser Raleigh was hit by one torpedo. It returned to service in February, 1942.

•  The Cruiser Honolulu suffered a near miss and received light damage. It remained in service.


•  The Destroyer Cassin was in drydock with the Downes and the Pennsylvania and was hit by one bomb and burned. It returned to service in February, 1944.

•  The Destroyer Downes was in drydock with the Cassin and the Pennsylvania and caught fire from the Cassin and burned. It returned to service in November, 1943.

•  The Destroyer Helm was under way to West Loch and was damaged by two near-miss bombs and continued to patrol. It was dry-docked on the 15th of January, 1942, and set sail again on the 20th of January, 1942.

•  The Destroyer Shaw was hit by three bombs. It returned to service in June, 1942.


•  The Minelayer Oglala was damaged by a torpedo hit on the Helena and capsized. It returned to service (as an engine-repair ship) in February, 1944.

•  The Repair Ship Vestal was hit by two bombs and blast and fire from the Arizona and was beached. It returned to service by August, 1942.

•  The Seaplane Tender Curtiss was hit by one bomb and one crashed Japanese aircraft. It returned to service in January, 1942. 19 dead.

•  The Harbour Tug Sotoyomo was damaged by explosion and fires on the Shaw and sunk. It returned to service in August, 1942.

•  YFD-2 (a yard floating dock) was damaged by 250-kilogram bombs and sunk. It returned to service on the 25th of January, 1942, servicing the Shaw.


After a systematic search for survivors, a United States officer was ordered to lead a formal salvage operation.

Around Pearl Harbour, divers from the Navy, the Pearl Harbour Naval Shipyard, and civilian contractors began work on the ships that could be refloated. They patched holes, cleared debris, and pumped water out of the ships. Navy divers worked inside the damaged ships. Within six months, five battleships and two cruisers were patched or refloated so they could be sent to shipyards in Pearl Harbour and on the mainland for extensive repair.

Intensive salvage operations continued for another year involving a total of about 20,000 man-hours under water. The Arizona and the target ship Utah were too heavily damaged for salvage and remain where they were sunk, with the Arizona becoming a war memorial. The Oklahoma was successfully raised but it was never repaired. It capsized while under tow to the mainland in 1947.

News coverage

The initial announcement of the attack on Pearl Harbour was made by the White House Press Secretary at 2:22 p.m. Eastern Time: “The Japanese have attacked Pearl Harbour from the air on all military and naval activities on the island of Oahu, the principal American base on the islands of Hawaii.” As information developed, the Press Secretary made a number of additional announcements to White House reporters over the course of the afternoon. Initial reports of the attack were transmitted over news wires at approximately 2:25 p.m. Eastern Time. The first radio coverage was on the news program, World News Today, at 2:30 p.m. Eastern time. A newspaper report at the time compared the attack to the Battle of Port Arthur in which the Imperial Japanese Navy attacked the Imperial Russian Navy 37 years earlier, triggering the Russo-Japanese War. Modern writers have continued to note parallels between the attacks.  


Following the attack, 15 Medals of Honour, 51 Navy Crosses, 53 Silver Stars, four Navy and Marine Corps Medals, one Distinguished Flying Cross, four Distinguished Service Crosses, one Distinguished Service Medal, and three Bronze Star Medals were awarded to the American servicemen who distinguished themselves in combat at Pearl Harbour. Additionally, a special military award, the Pearl Harbour Commemorative Medal, was later authorized for all military veterans of the attack.

The day after the attack, President Roosevelt delivered his famous Infamy Speech to a Joint Session of Congress, calling for a formal declaration of war on the Empire of Japan. Congress agreed to his request less than an hour later. On the 11th of December, Germany and Italy declared war on the United States, even though the Tripartite Pact did not require it. Congress issued a declaration of war against Germany and Italy later that same day. The United Kingdom declared war on Japan nine hours before the United States did, partially due to the Japanese attacks on Malaya, Singapore and Hong Kong, and partially due to the British Prime Minister Winston Churchill’s promise to declare war “within the hour” of a Japanese attack on the United States.

The attack was an initial shock to all of the Allies in the Pacific Theatre. Further losses compounded the alarming setback. Japan attacked the Philippines hours later. Because of the time difference, it was the 8th of December in the Philippines. Only three days after the attack on Pearl Harbour, the Battleships Prince of Wales and Repulse were sunk off the coast of Malaya, causing Churchill later to recollect “In all the war, I never received a more direct shock. As I turned and twisted in bed, the full horror of the news sank in. There were no British or American large warships in the Indian Ocean or the Pacific except the American survivors of Pearl Harbour, who were hurrying back to California. Over this vast expanse of waters Japan was supreme, and we were weak and naked everywhere”. Throughout the war, Pearl Harbour was frequently used in American propaganda.

One further consequence of the attack on Pearl Harbour and its aftermath was that Japanese-American residents and citizens were relocated to nearby Japanese-American internment camps. Within hours of the attack, hundreds of Japanese-American leaders were rounded up and taken to high-security camps. Eventually, almost all of the 110,000 Japanese Americans who lived on the West Coast of the United States were forced into interior camps. However only 1,200 to 1,800 people were interned in Hawaii, even though there were 150,000 Japanese-Americans there, which was over one third of the population.

The attack also had international consequences. The Canadian province of British Columbia, bordering the Pacific Ocean, had a large population of Japanese immigrants and there were a lot of Japanese-Canadian descendants. Pre-war tensions were made worse by the attack on Pearl Harbour, and this led to a reaction from the Government of Canada. The Canadian Government passed an order under the War Measures Act that allowed the forced removal of Canadians of Japanese descent from British Columbia as well as stopping them from returning to the province. On the 4th of March, regulations under the Act were adopted to evacuate Japanese-Canadians. As a result, 12,000 were interned in interior camps, 2,000 were sent to road camps and another 2,000 were forced to work in the prairies on sugar beet farms.

Strategic implications

Admiral Tadaichi summed up the Japanese result by saying, “We won a great tactical victory at Pearl Harbour and therefore lost the war.”

The attack on Pearl Harbour accomplished its objective. However, it turned out to be largely unnecessary. Admiral Yamamoto, who conceived the original plan, was not aware that the United States Navy had decided as far back as 1935 to abandon charging across the Pacific towards the Philippines in response to an outbreak of war. The United States instead adopted “Plan Dog” in 1940, which emphasized keeping the Imperial Japanese Navy out of the eastern Pacific and away from the shipping lanes to Australia, while the United States concentrated on defeating Nazi Germany.

Fortunately for the United States, the American aircraft carriers were untouched. Otherwise the Pacific Fleet’s ability to undertake offensive operations would have been impossible for a year or more. The elimination of the battleships left the United States Navy with no choice but to rely on its aircraft carriers and submarines. These were the very weapons that the United States Navy used to halt and repel the Japanese advance. While six of the eight battleships were repaired and returned to service, their relatively low speed and high fuel consumption limited their deployment. They were mainly used for shore bombardment. A major flaw of the Japanese strategic thinking was a belief that the ultimate Pacific battle would be fought by battleships in keeping with the doctrine of Admiral Mahan. As a result, Yamamoto and his successors saved their battleships for a “decisive battle” that never came.

The Japanese confidence in their ability to win a quick victory meant that they neglected Pearl Harbour’s naval repair yards, oil tank farms, submarine base, and the old headquarters building. All of these targets turned out to be more important than any battleship to the American war effort in the Pacific. The survival of the repair shops and fuel depots allowed Pearl Harbour to maintain logistical support for United States Navy operations such as the Doolittle Raid and the Battles of Coral Sea and Midway. United States submarines immobilized the heavy ships of the Imperial Japanese Navy and brought Japan’s economy to a virtual standstill by crippling the import of oil and raw materials. By the end of 1942, the import of raw materials was halved and the import of oil was almost negligible. Finally, the basement of the Old Administration Building was the home of the cryptanalytic unit which contributed significantly to the Midway ambush and the Submarine Force’s success.


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