Pearl Harbor

Attack on Pearl Harbour

Japan's surprise attack on the U.S. naval base at Pearl Harbor, Hawaii, on the morning of December 7, 1941, resulted in one of the most costly defeats in American history. Over 2,000 American military and civilian personnel were killed as a result of the attack, and all eight of the U.S. battleships moored in Pearl Harbor that morning were heavily damaged or destroyed. In addition, hundreds of U.S. planes on nearby airfields were destroyed or damaged in the assault.

Despite Japanese hopes that such a devastating attack would force the United States to petition for peace, the events of December 7 strengthened American resolve and silenced the isolationists who had opposed the possibility of the United States' entering the war. President Franklin D. Roosevelt's request to Congress to declare war against Japan on December 8 was almost unanimously approved, with only one dissenting voice in the House of Representatives.

Although the nature and timing of the December 7 attack took Americans completely by surprise, tension between the United States and Japan had been mounting for some time over Japanese imperialist ambitions in Asia. In July 1937 the Japanese army launched an invasion of China, having already invaded Manchuria and established the puppet regime of Manchukuo six years earlier. Relations between the


United States and Japan worsened in September 1940 when the Japanese signed the Tripartite Pact with Germany and Italy. When Japan occupied southern Indochina in July 1941, President Roosevelt responded by freezing Japanese assets in the United States and imposing an embargo on oil shipments to Japan. In a series of diplomatic exchanges in the summer and fall of 1941, the United States demanded that Japan withdraw its military forces from China and French Indochina.

As U.S.-Japanese relations worsened, Admiral Yamamoto Isoroku, commander of the Japanese combined fleet and Japan's chief naval strategist, planned a preemptive strike against the United States' Pacific fleet. Yamamoto, who had studied at Harvard, opposed war with the United States. In the event that war became inevitable, however, Yamamoto insisted that Japan ought to strike first with a massive surprise assault to immobilize the American fleet.

Commander Genda Minoru—an experienced carrier pilot and aerial tactician—helped to work out the details of the plan, which Yamamoto named Operation Z. On November 26, 1941, while U.S.-Japanese negotiations were ongoing, the strike force secretly set sail for Hawaii under the command of Vice Admiral Nagumo Chuichi.

Pearl Harbor before the attack

On the morning of the attack on Pearl Harbor, U.S. code-breakers in Washington, D.C., intercepted and decoded the final part of a 14-part diplomatic message stating that Japan would break off negotiations that day.

Correctly interpreting the message as an indication that Japan planned to go to war, but not knowing precisely where or when an attack would take place, General George C. Marshall attempted to radio Hawaii (among other places) to put the forces there on alert.

Atmospheric static necessitated the use of commercial telegraph to relay Marshall's warning to Lieutenant General Walter Short, commander of the U.S. forces in Hawaii. General Short would not receive the message until several hours after the attack had ended.


Submarine Periscope

In the predawn hours on December 7 Hawaiian time, the minesweeper Condor was patrolling the security zone near the entrance to Pearl Harbor when Ensign R. C. McCloy sighted a submarine periscope. Japanese aviators had opposed the inclusion of submarines in Yamamoto's attack plan, fearing that the subs—if spotted—would destroy the element of surprise.

The pilots were overruled, and a large fleet of submarines, including five short-range "midget" submarines, accompanied the aircraft carriers. The midget submarines were deployed at midnight on December 6, 10 miles from the harbor; their two-man crews were to attack any U.S. vessels attempting to enter or leave the harbor during the aerial assault.

Upon detecting one of the midget submarines at approximately 3:45 a.m., McCloy and Quartermaster Second Class R. C. Uttrick reported their discovery via signal lamp to the crew of the USS Ward. The Ward, a destroyer also on patrol near the harbor, conducted a sonar search but found nothing out of the ordinary.

Less than three hours later, however, Lieutenant William W. Outerbridge, the newly assigned captain of the Ward, was again summoned from his bunk; this time he spotted a midget submarine following in the wake of the USS Antares.

The Ward opened fire on the Japanese submarine and then followed up with a depth charge attack that sank the submarine. At 6:35 a.m. Outerbridge reported the incident to district command, but no general alarm was raised at the time. Admiral Husband E. Kimmel, commander of the Pacific Fleet, was awaiting verification of the report when the first wave of the aerial assault hit.

Japanese naval aircraft prepare to take off from an aircraft carrier to attack Pearl Harbor
during the morning of 7 December 1941

As the USS Ward fired the opening shots of the war in the Pacific, the first wave of 183 Japanese fighters, bombers, and torpedo planes was making its way toward the naval and air bases on the island of Oahu.

Led by Commander Fuchida Mitsuo, the first group of planes had lifted off from carrier flight decks approximately 230 miles north of Oahu at 6:00 a.m. At 7:02 a.m., two radar operators at Opana (near the northernmost tip of Oahu) detected a large body of aircraft approaching from the north. They immediately telephoned the information center at Fort Schafter, where the inexperienced duty officer Lieutenant Kermit Tyler dismissed the reports as insignificant.

Tyler knew that air force B-17 bombers were due in that morning from California en route to the Philippines, and he assumed that was what the radar operators had seen on their screens. Once again, therefore, no alarm was raised.

The air strike on Pearl Harbor was planned with two different options in mind. If surprise was achieved, then dive-bombers and torpedo planes were to strike the Pacific Fleet first, and the level bombers would follow up by dropping armor-piercing bombs over the harbor.

In the event that the U.S. forces had been alerted to the impending attack, then the dive-bombers in the first wave of the attack were to strike Wheeler and Hickam Airbases and the navy airfield on Ford Island.

When Fuchida fired a single flare at approximately 7:40 a.m. to indicate that surprise had been achieved, the commander of the fighter escort failed to acknowledge the signal. After a brief interval, Fuchida fired a second flare.

Tora! Tora! Tora!

The commander of the dive-bombers, Lieutenant Commander Takahashi Kuichi, mistook the second flare to mean that the defenders had been alerted, and so the dive-bombers proceeded to attack the airfields while the torpedo planes and level bombers concentrated their efforts on the fleet at Battleship Row.

As the first wave of Japanese planes reached Oahu at 7:53 a.m., Fuchida radioed back to the carriers the now-famous code words "Tora! Tora! Tora!" to indicate that total strategic and tactical surprise had been achieved. Nagumo relayed the message to Japan, letting forces there know that coordinated operations against Malaya, the Philippines, and the Dutch East Indies could move forward as well.

Upon nearing Oahu, the dive-bombers, or "Vals," divided into two groups, one targeting Hickam Field and Ford Island while the other went after Wheeler Airfield in central Oahu. The first group began bombing the army air base at Hickam Field at 7:55 a.m.

Japanese Zero plane crashed

The fact that the U.S. planes were lined up wingtip to wingtip as a precaution against possible sabotage made them easy targets for the Japanese bombers. The army suffered its heaviest casualties of the raid at Hickam Field, where 182 men were killed or unaccounted for. Wheeler Airfield was also heavily attacked; nearly two-thirds of the 140 planes on the ground at Wheeler were destroyed or put out of action.

The naval airbase at Ford Island lost nearly half its planes in the Japanese assault, and the one at Kaneohe Bay lost all but a few. Concurrent with the airfield bombings was the two-pronged attack on the U.S. Pacific fleet. Fortunately for the United States, none of its aircraft carriers was in port that morning.

The Japanese did, however, manage to inflict considerable damage to all eight of the battleships at Pearl Harbor, sinking five of them. By 8:00 a.m. Pearl Harbor was ablaze as a combination of torpedoes and armor-piercing bombs hit one U.S. vessel after another.

Especially spectacular was the explosion aboard the USS Arizona that resulted in the deaths of 1,177 men. The Arizona memorial still stands to commemorate all military personnel who lost their lives in the attack on Pearl Harbor.

A second wave of 167 more Japanese aircraft was launched approximately one hour after the first; 17 Zeros (fighter planes) targeted Kaneohe Naval Air Station, while 18 others attacked Wheeler Field and the Ewa Marine Corps air base.

Some 54 high-level bombers divided into three groups to attack Ford Island, Kaneohe, and Hickam Field; 80 dive-bombers attacked Pearl Harbor, including the naval yard where the drydocked battleship Pennsylvania was hit along with several destroyers. Near the end of the second wave, three bombs hit the destroyer Shaw in dry dock, setting off a spectacular explosion.

The Japanese suffered considerably more damage in the second wave than they had in the first, when they had caught the U.S. forces completely unaware; in all, Japanese losses included 29 planes, five midget submarines, and 55 men. The second and final wave of the attack was over by 9:45 a.m. Genda and Fuchida pressed for a follow-up attack, but the cautious Nagumo ordered the Japanese forces to withdraw.

As a result, U.S. oil storage depots and repair facilities escaped relatively unscathed. All but three of the 19 ships damaged in the attack would eventually be returned to service, and it would take just six months for the U.S. armed forces to turn the strategic tables in the Pacific with the decisive Battle of Midway (June 3–7, 1942).