Who attacked Pearl Harbor & Why quizlet?

Learn about this historic event that caused the United States to enter World War II.

Sunday, December 7, 1941, was supposed to be a day of rest for the military soldiers at Hawaii’s Pearl Harbor naval base on the island of Oahu. But at 7:55 a.m., Japanese fighter planes zoomed in without warning and attacked the United States Pacific fleet, or naval vessels, moored in the harbor. Thousands of lives would be lost that day.

It was, as then President Franklin Delano Roosevelt would call it, “a date which will live in infamy.”

THE PLAN

The sudden attack in Hawaii—at the time a territory of the United States, not a state—might have taken many by surprise, but the Japanese had been planning the operation for months.

Admiral Isoroku Yamamoto, commander in chief of the Japanese naval forces and architect of the Pearl Harbor attack, didn’t want a fight with America. But much of Europe and Asia, including Japan, were involved in World War II at the time. Yamamoto wanted to take over certain countries in southeastern Asia and use their oil to help fuel Japan’s military vehicles and naval fleet.

But because the U.S. base in Hawaii was relatively close to these countries, the Japanese worried that the United States would send soldiers from Pearl Harbor to defend the nations if they were attacked. By destroying the U.S. military presence in the region, the countries Japan wanted to target would be left vulnerable. So Yamamoto decided to move forward with a surprise attack on the U.S. fleet in Hawaii.

So on November 26, 1941, 31 warships carrying fighter planes and bombers slipped from Japan into the North Pacific. They moved silently until they closed in on the Hawaiian Islands. A small Japanese plane made a loop around the target and radioed back: “Pearl Harbor sleeps.”

THE ATTACK

At dawn on December 7, 350 planes launched in two waves from Japan’s ships. The bombers dropped bombs on American warships below, while the fighter planes targeted the U.S. aircraft on the ground so they couldn’t fight back.

Following both attacks, 19 U.S. naval vessels were sunk or damaged; 188 aircraft were destroyed. In all, 2,280 servicemen and women were killed, 1,109 were wounded. Sixty-eight civilians—people who are not in the military—also lost their lives. The attack lasted just under two hours.

THE AFTERMATH

Repair crews went to work on the ships. Except for the U.S.S. Arizona, Utah, and Oklahoma, every damaged ship returned to sea.

The day after the attack, the United States declared war on Japan, officially entering World War II. In the nearly four years that followed, the U.S. Navy sank all of the Japanese aircraft carriers, battleships, and cruisers that participated in the Pearl Harbor attack.

The United States and its allies—Britain, France, and Russia, among other countries—eventually won the war, defeating Japan and its allies, Germany and Italy.

Today visitors can tour the Pearl Harbor National Monument, built on the water above the wreckage of the U.S.S. Arizona, one of the eight battleships attacked and damaged during the fight. From there you can still glimpse at the remains of the sunken ship 40 feet below the water, a memorial to the brave people who fought in this important battle.

TEXT ADAPTED FROM PEARL HARBOR: A RETURN TO THE DAY OF INFAMY, OIL AND HONOR AT PEARL HARBOR, AND NATIONAL GEOGRAPHIC CONCISE HISTORY OF THE WORLD: AN ILLUSTRATED TIMELINE

World War II came to the United States of America on Sunday morning, 7 December 1941, with a massive surprise attack by the Imperial Japanese Navy. "Like a thunderclap from a clear sky," Japanese carrier attack planes (in both torpedo and high-level bombing roles) and bombers, supported by fighters, numbering 353 aircraft from six aircraft carriers, attacked the U.S. Pacific Fleet at Pearl Harbor in two waves, as well as nearby naval and military airfields and bases. The enemy sank five battleships and damaged three; and sank a gunnery training ship and three destroyers, damaged a heavy cruiser, three light cruisers, two destroyers, two seaplane tenders, two repair ships and a destroyer tender. Navy, Army, and Marine Corps facilities suffered varying degrees of damage, while 188 Navy, Marine Corps, and U.S. Army Air Force planes were destroyed. Casualties amounted to: killed or missing: Navy, 2,008; Marine Corps, 109; Army, 218; civilian, 68; and wounded: Navy, 710; Marine Corps, 69; Army, 364; civilian, 35. Japanese losses amounted to fewer than 100 men and 29 planes.

Sailors, Marines, and Soldiers fought back with extraordinary courage, often at the sacrifice of their own lives. Those without weapons to fight took great risk to save wounded comrades and to save their ships. Pilots took off to engage Japanese aircraft despite the overwhelming odds. Countless acts of valor went unrecorded, as many witnesses died in the attack. Fifteen U.S. Navy personnel were awarded the Medal of Honor — ranging from seaman to rear admiral — for acts of courage above and beyond the call of duty, ten of them posthumously.

Among the Sailors recognized with our nation's highest award for valor were Chief Water Tender Peter Tomich onboard the ex-battleship Utah, who sacrificed his life to prevent the boilers from exploding, enabling boiler room crews to escape before the ship capsized. Another was Chief Boatswain Edwin J. Hill, who cast off the lines as the battleship Nevada got underway, swam through the burning oil to get back on board his ship, where he was killed by Japanese strafing after being credited with saving the lives of many junior Sailors. Ensign Francis Flaherty and Seaman First Class J. Richard Ward, onboard the battleship Oklahoma, sacrificed their lives to enable turret crews to escape before the ship capsized. Onboard the battleship California, Chief Radioman Thomas J. Reeves, Machinist's Mate First Class Robert R. Scott and Ensign Herbert C. Jones stayed at their posts at the cost of their lives to keep power and ammunition flowing to the antiaircraft guns as long as possible. Rear Admiral Isaac C. Kidd and Captain Franklin Van Valkenburgh onboard the battleship Arizona, and Captain Mervyn S. Bennion onboard the battleship West Virginia directed the defense of their ships under heavy fire, until the ships were sunk and they were killed.

Japanese forces were astonished at the quick reaction and intensity of U.S. antiaircraft fire. That more Japanese aircraft were not shot down had nothing to do with the skill, training, or bravery of our Sailors and other servicemembers. Rather, U.S. antiaircraft weapons were inadequate in number and capability, for not only had the Japanese achieved tactical surprise, they achieved technological surprise with aircraft and weapons far better than anticipated — a lesson in the danger of underestimating the enemy that resonates to this day.

While damage to the U.S. Pacific Fleet's battleline proved extensive, it was not complete. The attack failed to damage any American aircraft carriers, which had been providentially absent from the harbor. Our aircraft carriers, along with supporting cruisers and destroyers and fleet oilers, proved crucial in the coming months. The Japanese focus on ships and planes spared our fuel tank farms, naval yard repair facilities, and the submarine base, all of which proved vital for the tactical operations that originated at Pearl Harbor in the ensuing months and played a key role in the Allied victory. American technological skill raised and repaired all but three of the ships sunk or damaged at Pearl Harbor. Most importantly, the shock and anger that Americans felt in the wake of the attack on Pearl Harbor united the nation and was translated into a collective commitment to victory in World War II.

Remembrance Resources
Resources for Pearl Harbor remembrance events may be found in our Pearl Harbor Remembrance section.

Why Pearl Harbor?
In the video sound bite below, Naval History and Heritage Command historian Robert J. Cressman discusses Japan's strategic objective for the attack on Pearl Harbor.

Click the links below for additional sets of video sound bites to hear Cressman answer questions about other aspects of the attack. Videos may be downloaded from DVIDS.

  • Japanese Planning and Preparation
  • The Fleet at Pearl Harbor
  • The First Minutes
  • Analysis of the Attack
  • American Response
  • Impact on American Public and Broader War
  • Impact on Fleet Composition 

The Navy Department Library Online Reading Room contains an overview of the Pearl Harbor attack; that page also provides most of the links given above.

Who actually attacked Pearl Harbor?

To blunt that response, Japan decided to attack the U.S Pacific Fleet at Pearl Harbor, hoping that the U.S would negotiate peace. The attack at Pearl Harbor was a huge gamble, but one which did not pay off. Though Japan took its objectives in the Pacific and Southeast Asia, the U.S did not respond as expected.

Who attacked the Pearl Harbor and why?

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 overseas territories of the United Kingdom, the Netherlands, and the United States.

Why did the Japanese attack Pearl Harbor?

President Roosevelt moved the US Pacific Fleet from California to Pearl Harbor in 1939. This move was a threat to Japan, who wanted to expand in the Pacific. Military leaders and politicians saw a war between the U.S. and Japan as inevitable, with the solution being to attack first. Japan did just that.