World War II: Attack on Pearl Harbor

"A Date Which Will Live in Infamy"

USS Arizona burns after the attack on Pearl Harbor. Photograph Courtesy of the US Naval History & Heritage Command

Pearl Harbor: Date & Conflict

The attack on Pearl Harbor occurred on December 7, 1941, during World War II (1939-1945).

Forces & Commanders

United States

  • Admiral Husband Kimmel
  • Major General Walter Short
  • 8 battleships, 8 cruisers, 30 destroyers, 4 submarines, 49 other ships


Attack on Pearl Harbor - Background

Through the late 1930s, American public opinion began to shift against Japan as that nation prosecuted a brutal war in China and sank a US Navy gunboat. Increasingly concerned about Japan's expansionist policies, the United States, Britain, and the Netherlands East Indies initiated oil and steel embargos against Japan in August 1941. The American oil embargo caused a crisis in Japan. Reliant on the US for 80% of its oil, the Japanese were forced to decide between withdrawaling from China, negotiating an end to the conflict, or going to war to obtain the needed resources elsewhere.

In an attempt to resolve the situation, Prime Minister Fumimaro Konoe asked President Franklin Roosevelt for a meeting to discuss the issues, but was told that such a conference could not be held until Japan left China. While Konoe was seeking a diplomatic solution, the military was looking south to the Netherlands East Indies and their rich sources of oil and rubber. Believing that an attack in this region would cause the US to declare war, they began planning for such an eventuality. On October 16, after arguing for more time to negotiate, Konoe resigned and was replaced by the pro-military General Hideki Tojo.

Attack on Pearl Harbor - Planning the Attack

In early 1941, as the politicians worked, Admiral Isoroku Yamamoto, commander of the Japanese Combined Fleet, had instructed his officers to begin planning for a preemtive strike against the US Pacific Fleet at their new base in Pearl Harbor, HI. It was believed that the American forces would have to be neutralized before an invasion of the Netherlands East Indies could begin. Drawing inspiration from the successful British attack on Taranto in 1940, Captain Minoru Genda devised a plan calling for aircraft from six carriers to strike the base.

By mid-1941, training for the mission was underway and efforts were being made to adapt torpedoes to run properly in Pearl Harbor's shallow waters. In October, the Japanse Naval General Staff approved Yamamoto's final plan which called for airstrikes and the use of five Type-A midget submarines. On November 5, with diplomatic efforts breaking down, Emperor Hirohito granted his approval for the mission. Though he had given permission, the emperor reserved the right to cancel the operation if diplomatic efforts succeeded. As negotiations continued to fail, he gave his final authorization on December 1.

In attacking, Yamamoto sought to eliminate the threat to Japanese operations to the south and lay the foundation for a swift victory before American industrial power could be mobilized for war. Assembling at Tankan Bay in the Kurile Islands, the main attack force consisted of the carriers Akagi, Hiryu, Kaga, Shokaku, Zuikaku, and Soryu as well as 24 supporting warships under the command of Vice Admiral Chuichi Nagumo. Sailing on November 26, Nagumo avoided major shipping lanes and succeeded in crossing the northern Pacific undetected.

Attack on Pearl Harbor - "A Date Which Will Live in Infamy"

Unaware of Nagumo's approach, the bulk of Admiral Husband Kimmel's Pacific Fleet was in port though his three carriers were at sea. Though tensions with Japan had been rising, an attack at Pearl Harbor was not expected, though Kimmel's US Army counterpart, Major General Walter Short, had taken anti-sabotage precautions. One of these included tightly parking his aircraft at the island's airfields. At sea, Nagumo began launching his first attack wave of 181 torpedo bombers, dive bombers, horizontal bombers, and fighters around 6:00 AM on December 7.

Supporting the aircraft, the midget subs had been launched as well. One of these was spotted by the minesweeper USS Condor at 3:42 AM outside of Pearl Harbor. Alerted by Condor, the destroyer USS Ward moved to intercept and sank it around 6:37 AM. As Nagumo's aircraft approached, they were detected by the new radar station at Opana Point. This signal was misinterpreted as a flight of B-17 bombers arriving from the US. At 7:48 AM, the Japanese aircraft descended on Oahu.

While the bombers and torpedo planes were ordered to select high value targets such as battleships and carriers, the fighters were to strafe air fields to prevent American aircraft from opposing the attack. Beginning their assault, the first wave struck Pearl Harbor as well as the airfields at Ford Island, Hickam, Wheeler, Ewa, and Kaneohe. Achieving complete surprise, the Japanese aircraft targeted the Pacific Fleet's eight battleships. Within minutes, the seven battleships along Ford Island's Battleship Row had taken bomb and torpedo hits.

While USS West Virginia quickly sank, USS Oklahoma capsized before settling on the harbor floor. Around 8:10 AM, an armor-piercing bomb penetrated USS Arizona's forward magazine. The resulting explosion sank the ship and killed 1,177 men. Around 8:30 AM there was a lull in the attack as the first wave departed. Though damaged, USS Nevada attempted to get underway and clear the harbor. As the battleship moved towards the exit channel, the second wave of 171 aircraft arrived. Quickly becoming the focus of the Japanese attack, Nevada beached itself at Hospital Point to avoid blocking Pearl Harbor's narrow entrance.

In the air, American resistance was negligible as the Japanese swarmed over the island. While elements of the second wave struck the harbor, others continued to hammer American airfields. As the second wave withdrew around 10:00 AM, Genda and Captain Mitsuo Fuchida lobbied Nagumo to launch a third wave to attack Pearl Harbor's ammunition and oil storage areas, dry docks, and maintenance facilities. Nagumo refused their request citing fuel concerns, the unknown location of the American carriers, and the fact that the fleet was within range of land-based bombers.

Attack on Pearl Harobr - Aftermath

Recovering his aircraft, Nagumo departed the area and began steaming west towards Japan. In the course of the attack the Japanese lost 29 aircraft and all five midget subs. Casualties totaled 64 killed and one captured. In Pearl Harbor, 21 American ships had been sunk or damaged. Of the Pacific Fleet's battleships, four were sunk and four badly damaged. Along with the naval losses, 188 aircraft had been destroyed with another 159 damaged. American casualties totaled 2,403 killed and 1,178 wounded.

Though the losses were catastrophic, the American carriers were absent and remained available to carry on the war. Also, Pearl Harbor's facilities remained largely undamaged and were able to support salvage efforts in the harbor and military operations abroad. In the months after the attack, US Navy personnel successfully raised many of ships lost in the attack. Sent to shipyards, they were updated and returned to action. Several of the battleships played a key role in the 1944 Battle of Leyte Gulf.

Addressing a joint session of Congress on December 8, Roosevelt described the previous day as a "date which will live in infamy." Outraged by the surprise nature of the attack (a Japanese note breaking off diplomatic relations had arrived late), Congress immediately declared war on Japan. In support of their Japanese ally, Nazi Germany and Fascist Italy declared war on the US on December 11 despite the fact they were not required to do so under the Tripartite Pact. This action was immediately reciprocated by Congress. In one bold stroke, the United States had become fully involved in World War II. Uniting the nation behind the war effort, Pearl Harbor led Japanese Admiral Hara Tadaichi to later comment, "We won a great tactical victory at Pearl Harbor and thereby lost the war."

Selected Sources