Attack on Pearl Harbor

Attack on Pearl Harbor Part of the Pacific Theater of World War II The attackers came in two waves. The first wave was detected by U.S. Army radar at  nautical miles ( km), but was misidentified as USAAF bombers from the mainland.[1] Date December 7, 1941 Location primarily Pearl Harbor, Hawaii, USA Casus belli Oil and trade embargo by the United States; diplomatic stalemate between Japan and the US. Result Decisive Japanese victory; United States declares war on the Empire of Japan and enters World War II on the side of Allies; Nazi Germany declares war on the United States. Combatants United States Empire of Japan Commanders Navy: Husband Kimmel Army: Walter Short Navy: Chuichi Nagumo Strength 8 battleships, 8 cruisers, 29 destroyers, 9 submarines, ~50 other ships, ~390 aircraft 6 aircraft carriers, 9 destroyers, 2 battleships, 2 heavy cruisers, 1 light cruiser, 8 tankers, 23 fleet submarines, 5 midget submarines, 414 aircraft Casualties 2 battleships sunk, 6 battleships damaged, 3 cruisers damaged, 2 destroyers sunk, 1 damaged, 1 other ship sunk, 3 damaged,[2] 188 aircraft destroyed, 155 aircraft damaged, 2,333 military and 55 civilians killed, 1,139 military and 35 civilians wounded[3]"#wp-_note-Pearl_Harbor_Congress_Report_Pg64">[4] 4 midget submarines sunk, 1 midget submarine run aground, 29 aircraft destroyed, 55 airmen, 9 submariners killed and 1 captured

Pacific campaigns 1941-42 French Indochina – Pearl Harbor – Thailand – Malaya – Hong Kong – Philippines – Guam – Wake – Dutch East Indies – New Guinea – Singapore – Australia – Indian Ocean – Doolittle Raid – Solomons – Coral Sea – Midway

Pacific Ocean theater Pearl Harbor – Midway – Solomons – Aleutians – Gilberts & Marshalls – Marianas & Palau – Volcano Is & Ryukyu Is

The attack on Pearl Harbor was a pre-emptive military strike on the United States Pacific Fleet base at Pearl Harbor, Hawaii by the Empire of Japan's Imperial Japanese Navy, on the morning of Sunday, 7 December, 1941. Two attack waves, totalling 350 aircraft were launched from six IJN aircraft carriers which destroyed two U.S. Navy battleships, one minelayer, two destroyers and 188 aircraft. Personnel losses were 2,333 killed and 1,139 wounded. Damaged warships included three cruisers, a destroyer, and six battleships. Of those six, one was deliberately grounded and was later refloated and repaired. Two sank at their berths but were later repaired and both rejoined the fleet late in the war. Vital fuel storage, shipyards, and submarine facilities were not hit. Japanese losses were minimal at 29 aircraft and five midget submarines, with 65 Japanese servicemen killed or wounded.

The pre-emptive strike's intent was to protect Imperial Japan's advance into Malaya and the Dutch East Indies – for their natural resources such as oil and rubber – by neutralizing the U.S. Pacific Fleet. Both the US and Japan had long-standing contingency plans for war in the Pacific, developed during the 1930s as tension between the two countries steadily increased, focusing on the other's battleships. Japan's expansion into Manchuria and later French Indochina were greeted with increasing levels of embargoes and sanctions from the United States. In 1940, the US halted further shipments of airplanes, parts, machine tools and aviation gas to Japan, which Japan interpreted as an unfriendly act.^[5] America continued to export oil to Japan, as it was understood in Washington that cutting off exports could mean Japanese retaliation.^[6] In the summer of 1941, the US ceased the export of oil to Japan due to Japan's continued aggressive expansionist policy and because an anticipated eventual American entrance to the war in Europe prompted increased stockpiling and less commercial use of gasoline.^[7] President Franklin D. Roosevelt had moved the fleet to Hawaii, and ordered a buildup in the Philippines, to reduce Japanese aggression in China and deter operations against others, including European colonies in Asia. The Japanese high command was certain any attack on the United Kingdom's colonies would inevitably bring the U.S. into the war.^[8] A pre-emptive strike appeared the only way Japan could avoid U.S. interference in the Pacific.

The attack was one of the most important engagements of World War II. Occurring before a formal declaration of war, it shocked the American public out of isolationism. Roosevelt called December 7, 1941 "… a date which will live in infamy."

Background to conflict

Tensions between Japan and the United States, Britain, and Netherlands increased significantly at the beginning of the more militaristic Showa era as Japanese nationalists and military leaders exerted increasing influence over government policy, promoting creation of the Greater East Asia Co-Prosperity Sphere as part of Japan's alleged "divine right" to unify Asia under emperor Showa's rule^[9] threatening American, French, British and Netherlands colonies in Asia. Increasingly, Japan's expansionist policies brought her into conflict with her neighbors, Russia and China, including Russian expansion into Manchuria and Korea (which Japan saw as a threat and which helped spark the Russo-Japanese War resulting in Japanese victory), Japan's invasion and seizure of Manchuria in 1931, Japan's persistent meddling in Chinese affairs, and finally, the full-scale invasion of China, which began at the Marco Polo Bridge in July 1937. These further complicated matters.

In response to international condemnation particularly by the United States, Britain and the Netherlands of the 1931 conquest of Manchuria and the establishment of the Manchukuo puppet government, in 1933 Japan withdrew from the League of Nations. On January 15, 1936, Japan withdrew from the Second London Naval Disarmament Conference which had refused parity of Japan's naval forces with other major navies (notably the U.S.). The 1937 Japanese attack against China was condemned by the U.S. and by several members of the League of Nations, particularly Britain, France, Australia, and the Netherlands. These states had economic and territorial interests, or formal colonies, in Southeast Asia, and had become increasingly alarmed at Japan's military power and willingness to use it, which they saw as threats to their control in Asia. In July 1939, the U.S. terminated the 1911 U.S.-Japan commercial treaty. These efforts failed to deter Japan from continuing the war in China nor from signing both the Anti-Comintern Pact with Nazi Germany and the Tripartite Pact with Germany and Italy forming the Axis Powers.

The Tripartite Pact, war with China, increasing militarization and Japan's withdrawal from the League of Nations eventually led the U.S. to embargo scrap metal and gasoline shipments to Japan and to constrain its actions and close the Panama Canal to Japanese shipping. In 1941, Japan moved into northern IndoChina.^[10] The U.S. responded by freezing Japan's assets in the U.S. embargoing oil.^[11] Oil was Japan's most crucial imported resource; more than 80 percent of Japan's oil imports at the time came from the United States^[12] To secure oil supplies, and other resources, Japanese planners had long been looking south, especially the Dutch East Indies. The Navy was (mistakenly) certain any attempt to seize this region would bring the U.S. into the war. In August 1941, Japanese Prime Minister Fumimaro Konoe proposed a summit with President Roosevelt to discuss differences. Roosevelt replied Japan must leave China before a summit meeting could be held.^{[citation needed]}

War

Emperor Shōwa

In July 1941, the Imperial Japanese Navy informed Hirohito its reserve bunker oil would be exhausted within two years if a new source was not acquired. On September 6, 1941, at the second Imperial Conference concerning attacks on Occidental colonies, Japanese leaders met to consider the attack plans prepared by Imperial General Headquarters, one day after the emperor had scolded General Sugiyama about the lack of success in China and the likely low chances of victory against the Occidental Powers.^[13]

Prime Minister of Japan Hideki Tojo

Prime Minister Konoe argued for more negotiations and possible concessions to avert war. Military leaders (e.g. Hideki Tojo, Sugiyama, and IJN Chief of Staff Fleet Admiral Osami Nagano) argued time had run out and additional negotiations would be pointless and urged swift military actions against all American and European colonies in Southeast Asia and Hawaii. Tojo argued yielding to the American demand to withdraw troops would wipe out all the fruits of the Second Sino-Japanese war, depress the army morale, endanger Manchukuo and jeopardize control of Korea and argued doing nothing is same as defeat and loss of national pride.

On October 16, 1941, Konoe resigned and proposed prince Naruhiko Higashikuni, who was also the choice of the Army and the Navy, as his successor. Hirohito choose Tojo instead, worried, as he told Konoe, about having the Imperial House being held responsible for a war against Western powers.^[14]

Kōichi Kido

On November 3, 1941, Nagano presented a detailed plan for the attack on Pearl Harbor to Hirohito.^[15] On 5 November, Hirohito approved the plan for a war against the United States, Great Britain and Holland, scheduled to start at the beginning of December if no significant changes were achieved through diplomacy.^[16]

On 30 November 1941, Prince Nobuhito Takamatsu warned his brother, Hirohito, the Navy felt the Empire could not fight more than two years against the United States and wished to avoid war. After consulting with Koichi Kido (who advised him to take his time until he was convinced) and Tojo, the Emperor then called Shigetaro Shimada and Nagano who reassured him war would be successful.^[17] On December 1, Hirohito finally sanctioned a "war against United States, Great Britain and Holland" in another Imperial Conference and commence with the surprise attack on the main American pacific force in Hawaii as prepared.^[18]

Prelude to battle

Intelligence gathering

Ensign Takeo Yoshikawa, a spy in Pearl Harbor for Imperial Japan.

On February 3, 1940, Yamamoto briefed Captain Kanji Ogawa of Naval Intelligence on the potential attack plan, asking him to start intelligence gathering on Pearl Harbor. Ogawa already had spies in Hawaii, including Japanese Consular officials with an intelligence remit, and he arranged for help from a German already living in Hawaii who was an Abwehr agent. None had been providing much militarily useful information. He planned to add 29-year-old Ensign Takeo Yoshikawa. By the spring of 1941, Yamamoto officially requested additional Hawaiian intelligence, and Yoshikawa boarded the liner Nitta-maru at Yokohama. He had grown his hair longer than military length, and assumed the cover name Tadashi Morimura.^[19]

Yoshikawa began gathering intelligence in earnest by taking auto trips around the main islands, and toured Oahu in a small plane, posing as a tourist. He visited Pearl Harbor frequently, sketching the harbor and location of ships from the crest of a hill. Once, he gained access to Hickam Field in a taxi, memorizing the number of visible planes, pilots, hangars, barracks and soldiers. He was also able to discover that Sunday was the day of the week on which the largest number of ships were likely to be in harbor, that PBY patrol planes went out every morning and evening, and that there was an antisubmarine net in the mouth of the harbor.^[20] Information was returned to Japan in coded form in Consular communications, and by direct delivery to intelligence officers aboard Japanese ships calling at Hawaii by consulate staff.

Planning

Main articles: Imperial Japanese Navy and Imperial Japanese Navy Air Service

Commander-in-Chief of the Combined Fleet Fleet Admiral Isoroku Yamamoto

Expecting war, and seeing an opportunity in the forward basing of the US Pacific Fleet at Hawaii, the Japanese began planning in early 1941 for an attack on Pearl Harbor. For the next several months, planning, and organizing a simultaneous attack on Pearl and invasion of British and Dutch colonies to the South occupied much of the Japanese Navy's time and attention. Pearl Harbor attack planning was a part of the Japanese expectation the U.S. would be inevitably drawn into the war after a Japanese attack against Malaya and Singapore.^[21]

The intent of a preemptive strike on Pearl Harbor was to neutralize American naval power in the Pacific, allowing operations against American, British, and Dutch colonies. Attacks on colonies were judged to depend on successfully dealing with the American Pacific Fleet. Surprise attack posed a twofold difficulty. First, the Pacific Fleet was a formidable force, and would not be easy to defeat or to surprise. Second, for aerial attack, Pearl Harbor's shallow waters made using conventional air-dropped torpedoes ineffective. On the other hand, Hawaii's isolation meant a successful surprise attack could not be blocked or quickly countered by forces from the continental U.S.

Several Japanese naval officers had been impressed by the British Operation Judgement, in which 21 obsolete Fairey Swordfish disabled half the Regia Marina. Admiral Yamamoto dispatched a delegation to Italy, which concluded a larger and better-supported version of Cunningham's strike could force the U.S. Pacific Fleet to retreat to bases in California, thus giving Japan the time necessary to establish a "barrier" defense to protect Japanese control of the Dutch East Indies. The delegation returned to Japan with information about the shallow-running torpedoes Cunningham's engineers had devised.^{[citation needed]}

Japanese strategists were undoubtedly influenced by Heihachiro Togo's surprise attack on the Russian Pacific Fleet at Port Arthur in 1905, and may have been influenced by U.S. Admiral Harry Yarnell's performance in the 1932 joint Army-Navy exercises, which simulated an invasion of Hawaii. Yarnell, as commander of the attacking force, placed his carriers northwest of Oahu and simulated an air attack. The exercise's umpires noted Yarnell's aircraft were able to inflict serious "damage" on the defenders, who for 24 hours after the attack were unable to locate his force.

Yamamoto's emphasis on destroying the American battleships was in keeping with the Mahanian doctrine shared by all major navies during this period, including the U.S. Navy and Royal Navy.^[22]

Planner Commander Minoru Genda stressed surprise would be critical.

In a letter dated January 7, 1941 Yamamoto finally delivered a rough outline of his daring plan to Koshiro Oikawa, then Navy Minister, from whom he also requested to be made Commander in Chief of the air fleet to attack Pearl Habour.

A few weeks later, in yet another letter, this time directed at Takijiro Onishi—chief of staff of the Eleventh Air Fleet—Yamamoto requested Onishi study the technical feasibility of an attack against the American base. After consulting first with Kosei Maeda, an expert on aerial torpedo warfare, and being told the harbour's shallow waters rended such an attack almost impossible, Onsihi summonded Commander Minoru Genda. After studying the original proposal put forth by Yamamoto, Genda agreed, "the plan is difficult but not impossible".

During the following weeks, Genda expanded Yamamoto's original plan, highlighting the importance of it being carried out early in the morning and in total secrecy, employing an aircraft carrier force, several different types of bombing, among other aspects which included an actual landing in Hawaii, aimed at forcing American forces to retreat towards the West Coast.^[23]

By April 1941, the Pearl Harbor plan became known as Operation Z, after the famous Z signal given by Admiral Tōgō at Tsushima.^{[citation needed]}

Over the summer, pilots trained in earnest on the Japanese island of Kyūshū. Genda chose Kagoshima City for a training area because its geography and infrastructure presented most of the same problems bombers would face at Pearl Harbor. In training, each crew would fly over the 5000-foot (1500 m) mountain behind Kagoshima, dive down into the city, dodging buildings and smokestacks before dropping to an altitude of 25 feet (7 m) at the piers. Bombardiers would release a torpedo at a breakwater some 300 yards (270 m) away.^[24]

Yet even skimming the water would not solve the problem of torpedoes bottoming in the shallow waters of Pearl Harbor. Japan created and tested modifications allowing successful shallow water drops. The effort resulted in a heavily modified version of the Type 91 torpedo which inflicted most of the ship damage during the attack. Japanese weapons technicians also produced special armor-piercing bombs by fitting fins and release shackles to 14 and 16 inch (356 and 406 mm) naval shells. These were able to penetrate the lightly armored decks of the old battleships.

The striking force

Main articles: Carrier Striking Task Force and Attack on Pearl Harbor order of battle

Admiral Chuichi Nagumo

On November 26 1941, the day the Hull note was received from United States Secretary of State Cordell Hull, the Japanese carrier battle group, already assembled in Hitokappu Wan in the Kurile Islands, sortied for Hawaii, under strict radio silence.

The Kido Butai, the Combined Fleet's main carrier force, under the command of Admiral Chuichi Nagumo, included six aircraft carriers carriers (the most powerful carrier force with the greatest concentration of air power in the history of naval warfare to date),^[25] which embarked 359 airplanes,^[26] organized as the First Air Fleet. The carriers Akagi (flag), Kaga, Sōryū, Hiryū, and the newest, Shōkaku and Zuikaku, had 135 Mitsubishi A6M Type 0 fighters (Allied codename "Zeke", commonly called "Zero"), 171 Nakajima B5N Type 97 torpedo bombers (Allied codename "Kate"), and 108 Aichi D3A Type 99 dive bombers (Allied codename "Val") aboard. Two fast battleships, two heavy cruisers, one light cruiser, nine destroyers, and three fleet submarines provided escort and screening. In addition, the Advanced Expeditionary Force included 20 fleet and five two-man Ko-hyoteki-class midget submarines, which were to gather intelligence and sink U.S. vessels attempting to flee Pearl Harbor during or soon after the attack. It also had eight oilers for underway fueling.^[27]

The execute order

Fleet Admiral Osami Nagano

On December 1, 1941, after the striking force was en route, Chief of Staff Nagano gave a verbal directive to commander of the Combined Fleet Admiral Isoroku Yamamoto, informing him:

Japan has decided to open hostilities against the United States, United Kingdom, and the Netherlands early in December...Should it appear certain that Japanese-American negotiations will reach an amicable settlement prior to the commencement of hostilities, it is understood that all elements of the Combined Fleet are to be assembled and returned to their bases in accordance with separate orders.^[28]

[The Kido Butai will] proceed to the Hawaiian Area with utmost secrecy and, at the outbreak of the war, will launch a resolute surprise attack on and deal a fatal blow to the enemy fleet in the Hawaiian Area. The initial air attack is scheduled at 0330 hours, X Day.^[28]

Upon completion, the force was to return to Japan, re-equip, and re-deploy for "Second Phase Operations".

Finally, Order number 9, issued on 1 December 1941 by Nagano, instructed Yamamoto to crush hostile naval and air forces in Asia, the Pacific and Hawaii, promptly sieze the main U.S., British, and Dutch bases in East Asia and "capture and secure the key areas of the southern regions".^[28]

On the home leg, the force was ordered to be alert for tracking and counterattacked by the Americans, and to return to the friendly base in the Marshall Islands, rather than the Home Islands.^[29]

|- |

Lieutenant General Walter C. Short, commanding general of the Army post at Pearl Harbor

|} U.S. civil and military intelligence had, amongst them, good information suggesting additional Japanese aggression throughout the summer and fall before the attack. At the time, none specifically indicated an attack against Pearl Harbor, nor has any doing so been identified since. Public press reports during summer and fall, including Hawaiian newspapers, contained extensive reports on the growing tension in the Pacific. Late in November, all Pacific commands, including both the Navy and Army in Hawaii, were separately and explicitly warned^[30] war with Japan was expected in the very near future, and it was preferred that Japan make the first hostile act as they were apparently preparing to do.^[31] It was felt that war would most probably start with attacks in the Far East: the Philippines,^[32] Indochina, Thailand, or the Russian Far East. The warnings were not specific to any area, noting only war with Japan was expected in the immediate short term and all commands should act accordingly. Had any of these warnings produced an active alert status in Hawaii, the attack might have been resisted more effectively, and perhaps resulted in less death and damage. On the other hand, recall of men on shore leave to the ships in harbor might have led to still more being casualties from bombs and torpedoes, or trapped in capsized ships by shut watertight doors (as the attack alert status would have required),^[33] or killed (in their obsolescent and obsolete aircraft) by more experienced Japanese aviators. When the attack actually arrived, Pearl Harbor was effectively unprepared: anti-aircraft weapons not manned, most ammunition locked down, anti-submarine measures not implemented (e.g., no torpedo nets in the harbor), combat air patrol not flying, available scouting aircraft not in the air at first light, Air Corps aircraft parked wingtip to wingtip to reduce sabotage risks (not ready to fly at a moment's warning), and so on.

By 1941, U.S. signals intelligence, through the Army's Signal Intelligence Service and the Office of Naval Intelligence's OP-20-G, had intercepted and decrypted considerable Japanese diplomatic and naval cipher traffic, though nothing actually carrying significant information about Japanese military plans in 1940-41. Decryption and distribution of this intelligence, including such decrypts as were available, was capricious and sporadic, and can be blamed in part on lack of manpower. At best, the information was fragmentary, contradictory, or poorly distributed, and was almost entirely raw, without supporting analysis. It was also incompletely understood by decision makers. Nothing in it pointed directly to an attack at Pearl Harbor, and a lack of awareness of Imperial Navy capabilities led to a widespread underlying belief Pearl Harbor was safely out of harm's way. Only one message from the Hawaiian Japanese consulate (sent on 6 December), in a low level consular cipher, included mention of an attack at Pearl; it was not decrypted until 8 December.^[34]

In 1924, General William L. Mitchell produced a 324-page report warning future wars (including with Japan) would include a new role for aircraft, against existing ships and facilities. He even discussed the possibility of an air attack on Pearl Harbor but his warnings were ignored. Navy Secretary Knox had also appreciated the possibility of an attack at Pearl in a written analysis shortly after taking office. American commanders had been warned tests demonstrated shallow-water aerial torpedo attacks were possible, but no one in charge in Hawaii fully appreciated its import. A war game surprise attack against Pearl Harbor in 1932 had been judged a success and to have caused considerable damage.

Nevertheless, because it was believed Pearl Harbor had natural defenses against torpedo attack (e.g., the shallow water), the Navy did not deploy torpedo nets or baffles, which were judged to interfere with ordinary operations. And as a result of limited numbers of long-range aircraft (including Army Air Corps bombers, responsible for search by a prewar arrangement), reconnaissance patrols were not being made as often or as far out as required for adequate coverage against possible surprise attack; they improved considerably, with fewer planes,^{[citation needed]} after the attack. The Navy had 33 PBYs in the islands, but only three on patrol at the time of the attack.^[35] Hawaii was low on the priority list for the B-17s finally becoming available for the Pacific, largely because General MacArthur in the Philippines was successfully demanding as many as could be made available to the Pacific (where they were intended as a deterrent); even the British, which had contracted for them, agreed to accept fewer to facilitate this buildup. At the time of the attack, Army and Navy were both on training status rather than operational alert. There was also confusion about the Army's readiness status as General Short had changed the alert level designations without clearly informing Washington. Most of the Army's mobile anti-aircraft guns were secured, with ammunition locked down in armories. To avoid upsetting property owners, and in keeping with Washington's admonition not to alarm civil populations (e.g., in the late November war warning messages from the Navy and War Departments), guns were not dispersed around Pearl Harbor (i.e., on private property). Additionally, aircraft were parked on airfields to lessen the risk of sabotage, not in anticipation of air attack, in keeping with Short's (uncontradicted) interpretation of the war warnings.

Chester Nimitz said later, "It was God's mercy that our fleet was in Pearl Harbor on December 7, 1941.". Nimitz believed if Kimmel had discovered the Japanese approach, he would have sortied to meet them. With the American carriers absent and Kimmel's battleships at a severe disadvantage to the Japanese carriers, the likely result would have been the sinking of the American battleships at sea in deep water, where they would have been lost forever with tremendous casualties (as many as twenty thousand dead), instead of in Pearl Harbor, where the crews could easily be rescued, and six battleships ultimately raised.^[36]

Breaking off negotiations

Part of the Japanese plan for the attack included breaking off negotiations with the United States 30 minutes before the attack began. Diplomats from the Japanese Embassy in Washington, including the Japanese Ambassador, Admiral Kichisaburo Nomura, and special representative Saburo Kurusu, had been conducting extended talks with the State Department regarding the U.S. reactions to the Japanese move into Việt Nam in the summer (see above).

In the days before the attack, a long 14-part message was sent to the Embassy from the Foreign Office in Tokyo (encrypted with the Type 97 cryptographic machine, in a cipher named PURPLE by U.S. cryptanalysts), with instructions to deliver it to Secretary of State Cordell Hull at 1 p.m. Washington time. The last part arrived late Saturday night (Washington time) but due to decryption and typing delays, and to Tokyo's failure to stress the crucial necessity of the timing, her Embassy personnel did not deliver the message breaking off negotiations to Secretary Hull until several hours after the attack.

The United States had decrypted the 14th part well before the Japanese Embassy managed to, and long before the Embassy managed a fair typed copy. The final part, with its instruction for the time of delivery, prompted General George Marshall, Army Chief of Staff, to send that morning's warning message to Hawaii.^[37] There were delays because General Marshall couldn't be found (he was out for a morning horseback ride), trouble with the Army's long distance communication system, a decision not to use the Navy's parallel facilities despite an offer to permit it, and various troubles during its travels over commercial cable facilities (somehow its "urgent" marking was misplaced, adding additional hours to its travel time). It was actually delivered to General Walter Short, by a young Japanese-American cycle messenger, several hours after the attack had ended.

Japanese records, admitted into evidence during Congressional hearings on the attack after the War, establish that the Japanese government had not even written a declaration of war until hearing news of the successful attack. The two-line declaration of war was finally delivered to U.S. Ambassador Grew in Tokyo about 10 hours after the attack was over. He was allowed to transmit it to the United States where it was received late Monday afternoon (Washington time).

Approach and attack

Nakajima nicknamed "Kate" taking off from aircraft carrier Shokaku for Pearl Harbor on the morning while a crewman with hachimaki works

Reconaissance and launch

During the operation, according to General Order 7, the Kido Butai was instructed to attack the enemy fleet if encountered, since war was officially declared by the Japanese government.^[38]. A commercial freighter had scouted the proposed route earlier in the year. Yamamoto and senior Navy staff intended there be three waves of attack, but Vice Admiral Chuichi Nagumo decided to break off after the second. There were also supporting submarines and midget submarines assigned to engage U.S. ships should they succeed in leaving the harbor. The location of the attack force remained unknown to the U.S. until after the Japanese ships were already returning to the Eastern Pacific; they were not located after the attack, in part because such searches as were organized were conducted south of Oahu despite aircraft and radar reports of the attacking force that morning. (This was partially due to direction finding mistakenly placing searchers on a reciprocal bearing.^[39]) The total number of planes involved in the attack was 350.^[40] 39 were engaged in protection of the Kido Butai during the attack.^[41]

The strike launched 200 nautical miles (370 km) north of Oahu,^[42] with orders to attack "a powerful enemy surface fleet" if one appeared.^[43]

Crew members aboard Shokaku waving to the planes taking off for Pearl Harbor.

On December 5, Yoshikawa went on his final “sightseeing” flight over Pearl Harbor in a small Piper Cub.^[44] Via the Consulate, he cabled Tokyo that there were 8 battleships,^[45] 3 light cruisers, and 16 destroyers in the harbor.^[46] Also, two Aichi E12A Type 0 float scouts (Allied codename "Jake"), one each from Tone and Chikuma (Mikuma's Cruiser Division 8) secretly scouted the Lahaina Road anchorage and Pearl Harbor^[47] for the Pacific Fleet.

Captain Mitsuo Fuchida

Aichi D3A "Val" dive bombers preparing for take off for Pearl Harbor

First wave

The first wave of attack consisted of 49 B5Ns, 51 D3As, 40 B5Ns, and 43 A6Ms (a total of 183 aircraft), launched north of Oahu, commanded by Captain Mitsuo Fuchida. It comprised:

• 1st Group
  • 50 Nakajima B5Ns armed with 800 kg (1760 lb) Armor piercing bombs, in four sections.
  • 40 B5Ns armed with Type 91 torpedoes, also in four sections.
• 2nd Group - 55 Aichi D3As armed with 550 lb general purpose bombs
  • 27 D3As - Hangars and aircraft on Ford Island
  • 27 D3As - Hangars and aircraft on Wheeler Field
• 3rd Group - 45 A6Ms for air control and strafing, divided into three sections:
  • 18 A6Ms - Ford Island and Hickam Field
  • 15 A6Ms - Wheeler Field and Barbers Point
  • 12 A6M - Kāneʻohe Marine Corps Air Station,^[48]

The first attack wave divided into 3 groups. One unit went to Wheeler Field. Each of the aerial waves started with the bombers and ended with the fighters to deter pursuit.

At 03.42^[49] Hawaiian Time, even before Nagumo began launching, the minesweeper USS Condor spotted a midget submarine outside the harbor entrance and alerted destroyer USS Ward. Ward carried out an unsuccessful search. The first shots fired, and the first casualties in the attack, occurred when Ward eventually attacked and sank a midget submarine, possibly the same one, at 06:37.

Kazuo Sakamaki, first POW for the United States in World War II.

Five midget submarines had been assigned to torpedo U.S. ships after the bombing started. None of these returned, and only four have since been found. Of the ten sailors aboard, nine died; the only survivor, Kazuo Sakamaki, was captured, becoming the first Japanese prisoner of war.^[50] United States Naval Institute analysis of photographs from the attack, conducted in 1999, indicates one of these mini-subs entered the harbor and successfully fired a torpedo into the USS West Virginia, what may have been the first shot by the attacking Japanese. Her final disposition is unknown.^[51]

On the morning of the attack, the Army's Opana Point station (an SCR-270 radar, located near the northern tip of Oahu, which had not entered official service, having been in training mode for months), detected the first wave of Japanese planes and called in a warning. Although the operators at Opana Point reported a target echo larger than anything they had ever seen, an untrained new officer at the new and only partially activated Intercept Center, Lieutenant Kermit A. Tyler, presumed the scheduled arrival of six B-17 bombers was the cause because of the direction from which the aircraft were coming (only a few degrees separated the two inbound courses);^[52] because he presumed the operators had never seen a formation as large as the U.S. bombers' on radar;^[53] and possibly because the operators had only seen the lead element of incoming attack.

Several U.S. aircraft were shot down as the first wave approached land; one at least radioed a somewhat incoherent warning. Other warnings were still being processed, or awaiting confirmation, when the planes began bombing and strafing. It is not clear any warnings would have had much effect even had they been interpreted correctly and much more promptly. For instance, the results the Japanese achieved in the Philippines were essentially the same as at Pearl Harbor, tho