Attack on Pearl Harbor

Attack on Pearl Harbor
Part of the Asia and the Pacific Theater of World War II
Attack on Pearl Harbor Japanese planes view.jpg
Photograph of Battleship Row taken from a Japanese plane at the beginning of the attack. The explosion in the center is a torpedo strike on USS West Virginia. Two attacking Japanese planes can be seen: one over USS Neosho and one over the Naval Yard.
DateDecember 7, 1941; 76 years ago (1941-12-07)
LocationPrimarily Pearl Harbor, Hawaii Territory, U.S.

Major Japanese tactical victory; precipitated the entrance of the United States into World War II

 United States Japan
Commanders and leaders
United States Navy ADM Husband E. Kimmel
LTG Walter Short
Empire of Japan VADM Chūichi Nagumo
ADM Isoroku Yamamoto
CDR Mitsuo Fuchida
8 battleships
8 cruisers
30 destroyers
4 submarines
3 USCG Cutters[nb 1]
47 other ships[4]
≈390 aircraft
Mobile Unit:
6 aircraft carriers
2 battleships
2 heavy cruisers
1 light cruiser
9 destroyers
8 tankers
23 fleet submarines
5 midget submarines
414 aircraft
Casualties and losses
4 battleships sunk
4 battleships damaged
1 ex-battleship sunk
1 harbor tug sunk
3 cruisers damaged[nb 2]
3 destroyers damaged
3 other ships damaged
188 aircraft destroyed
159[6] aircraft damaged
2,335 killed
1,143 wounded
4 midget submarines sunk
1 midget submarine grounded
29 aircraft destroyed
64 killed
1 sailor captured[7]
Civilian casualties
68 killed[8][9]
35 wounded[10]
3 aircraft shot down

The attack on Pearl Harbor was a surprise military strike by the Imperial Japanese Navy Air Service against the United States naval base at Pearl Harbor, Hawaii Territory, on the morning of December 7, 1941. The attack, also known as the Battle of Pearl Harbor,[11] led to the United States' entry into World War II. The Japanese military leadership referred to the attack as the Hawaii Operation and Operation AI,[12][13] and as Operation Z during its planning.[14]

Japan intended the attack as a preventive action to keep the U.S. Pacific Fleet from interfering with its planned military actions in Southeast Asia against 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 U.S.-held Philippines, Guam and Wake Island and on the British Empire in Malaya, Singapore, and Hong Kong.[15]

The attack commenced at 7:48 a.m. Hawaiian Time (18:18 GMT).[nb 3][16] The base was attacked by 353[17] Imperial Japanese aircraft (including fighters, level and dive bombers, and torpedo bombers) in two waves, launched from six aircraft carriers.[17] All eight U.S. Navy battleships were damaged, with four sunk. All but the USS Arizona were later raised, and six 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,[nb 4] and one minelayer. One hundred eighty-eight U.S. aircraft were destroyed; 2,403 Americans were killed and 1,178 others were wounded.[19] Important base installations such as the power station, dry dock, shipyard, maintenance, and fuel and torpedo storage facilities, as well as the submarine piers and headquarters building (also home of the intelligence section), were not attacked. Japanese losses were light: 29 aircraft and five midget submarines lost, and 64 servicemen killed. One Japanese sailor, Kazuo Sakamaki, was captured.

The surprise attack came as a profound shock to the American people and led directly to the American entry into World War II in both the Pacific and European theaters. The following day, December 8, the United States declared war on Japan,[20][21] and several days later, on December 11, Germany and Italy each declared war on the U.S. The U.S. responded with a declaration of war against Germany and Italy. Domestic support for non-interventionism, which had been fading since the Fall of France in 1940,[22] disappeared.[21]

There were numerous historical precedents for unannounced military action by Japan, but the lack of any formal warning, particularly while negotiations were still apparently ongoing, led President Franklin D. Roosevelt to proclaim December 7, 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 Harbor was later judged in the Tokyo Trials to be a war crime.[23][24]

Background to 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. However, 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 endeavored to secure enough independent resources to attain victory on the mainland. The "Southern Operation" was designed to assist these efforts.[25]

Pearl Harbor on October 30, 1941, looking southwest

Starting in December 1937, events such as the Japanese attack on USS Panay, the Allison incident, and the Nanking Massacre swung Western public opinion sharply against Japan. Fearing Japanese expansion,[26] the United States, United Kingdom, and France assisted China with its loans for war supply contracts.

In 1940, Japan invaded French Indochina, attempting to stymie the flow of supplies reaching China. The United States halted shipments of airplanes, parts, machine tools, and aviation gasoline to Japan, which the latter perceived as an unfriendly act.[nb 5] The United States did not stop oil exports, however, partly because of the prevailing sentiment in Washington: given Japanese dependence on American oil, such an action was likely to be considered an extreme provocation.[28][29]

In mid-1940, President Franklin D. Roosevelt moved the Pacific Fleet from San Diego to Hawaii.[30] He also ordered a military buildup 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 any attack on the United Kingdom's Southeast Asian colonies, including Singapore,[31] would bring the U.S. into the war, a devastating preventive strike appeared to be the only way to prevent American naval interference.[32] An invasion of the Philippines was also considered necessary by Japanese war planners. The U.S. War Plan Orange had envisioned defending the Philippines with a elite force of 40,000 men; this option was never implemented due to opposition from Douglas MacArthur, who felt he would need a force ten times that size.[33][self-published source] By 1941, U.S. planners expected to abandon the Philippines at the outbreak of war. Late that year, Admiral Thomas C. Hart, commander of the Asiatic Fleet, was given orders to that effect.[34]

The U.S. 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.[35] Because of this decision, Japan proceeded with plans to take the oil-rich Dutch East Indies.[nb 6] On August 17, Roosevelt warned Japan that America was prepared to take opposing steps if "neighboring countries" were attacked.[37] The Japanese were faced with a dichotomy—either withdraw from China and lose face, or seize new sources of raw materials in the resource-rich European colonies of Southeast Asia.

Japan and the U.S. engaged in negotiations during 1941, attempting 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 other nations reciprocated. Washington rejected these proposals. Japanese Prime Minister Konoye then offered to meet with Roosevelt, but Roosevelt insisted on reaching an agreement before any meeting.[38] The U.S. ambassador to Japan repeatedly urged Roosevelt to accept the meeting, warning that it was the only way to preserve the conciliatory Konoye government and peace in the Pacific.[39] However, his recommendation was not acted upon. The Konoye government collapsed the following month, when the Japanese military rejected a withdrawal of all troops from China.[40]

Japan's final proposal, delivered on November 20, offered to withdraw from southern Indochina and to refrain from attacks in Southeast Asia, so long as the United States, United Kingdom, and Netherlands ceased aid to China and lifted their sanctions against Japan.[40] The American counter-proposal of November 26 (November 27 in Japan), the Hull note, required Japan completely evacuate China without conditions and conclude non-aggression pacts with Pacific powers. On November 26 in Japan, the day before the note's delivery, the Japanese task force left port for Pearl Harbor.

Military planning

Preliminary planning for an attack on Pearl Harbor 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 auspices of Admiral Isoroku Yamamoto, then commanding Japan's Combined Fleet.[41] He won assent to formal planning and training for an attack from the Imperial Japanese Navy General Staff only after much contention with Naval Headquarters, including a threat to resign his command.[42] Full-scale planning was underway by early spring 1941, primarily by Rear Admiral Ryūnosuke Kusaka, with assistance from Captain Minoru Genda and Yamamoto's Deputy Chief of Staff, Captain Kameto Kuroshima.[43] The planners studied the 1940 British air attack on the Italian fleet at Taranto intensively.[nb 7][nb 8]

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 November 5, after the third of four Imperial Conferences called to consider the matter.[46] Final authorization was not given by the emperor until December 1, after a majority of Japanese leaders advised him the "Hull Note" would "destroy the fruits of the China incident, endanger Manchukuo and undermine Japanese control of Korea."[47]

By late 1941, many observers believed that hostilities between the U.S. and Japan were imminent. A Gallup poll just before the attack on Pearl Harbor found that 52% of Americans expected war with Japan, 27% did not, and 21% had no opinion.[48] While U.S. Pacific bases and facilities had been placed on alert on many occasions, U.S. officials doubted Pearl Harbor would be the first target; instead, they expected the Philippines would be attacked first. This presumption was due to the threat that the air bases throughout the country and the naval base at Manila posed to sea lanes, as well as to the shipment of supplies to Japan from territory to the south.[49] They also incorrectly believed that Japan was not capable of mounting more than one major naval operation at a time.[50]


The Japanese attack had several major aims. First, it intended to destroy important American fleet units, thereby preventing the Pacific Fleet from interfering with Japanese conquest of the Dutch East Indies and Malaya and to enable Japan to conquer Southeast Asia without interference. Second, it was hoped to buy time for Japan to consolidate its position and increase its naval strength before shipbuilding authorized by the 1940 Vinson-Walsh Act erased any chance of victory.[51][52] Third, to deliver a blow to America's ability to mobilize its forces in the Pacific, battleships were chosen as the main targets, since they were the prestige ships of any navy at the time.[51] Finally, it was hoped that the attack would undermine American morale such that the U.S. government would drop its demands contrary to Japanese interests, and would seek a compromise peace with Japan.[53][54]

Striking the Pacific Fleet at anchor in Pearl Harbor carried two distinct disadvantages: the targeted ships would be in very shallow water, so it would be relatively easy to salvage and possibly repair them; and most of the crews would survive the attack, since many would be on shore leave or would be rescued from the harbor. A further important disadvantage—this of timing, and known to the Japanese—was the absence from Pearl Harbor of all three of the U.S. Pacific Fleet's aircraft carriers (Enterprise, Lexington, and Saratoga). IJN top command was attached to Admiral Mahan's "decisive battle" doctrine, especially that of destroying the maximum number of battleships. Despite these concerns, Yamamoto decided to press ahead.[55][page needed]

Japanese confidence in their ability to achieve a short, victorious war also meant other targets in the harbor, especially the navy yard, oil tank farms, and submarine base, were ignored, since—by their thinking—the war would be over before the influence of these facilities would be felt.[56]

Other Languages
azərbaycanca: Pörl-Harbora hücum
Bikol Central: Ataki sa Pearl Harbor
한국어: 진주만 공격
Bahasa Indonesia: Pengeboman Pearl Harbor
Lëtzebuergesch: Ugrëff op Pearl Harbor
Bahasa Melayu: Serangan Pearl Harbor
日本語: 真珠湾攻撃
oʻzbekcha/ўзбекча: Pyorl Harborga hujum
Simple English: Attack on Pearl Harbor
slovenščina: Napad na Pearl Harbor
srpskohrvatski / српскохрватски: Napad na Pearl Harbor
Lingua Franca Nova: Ataca a Pearl Harbor