The Japanese attack on Pearl Harbor led to America’s entry into WWII. This only makes it one of the biggest events in history. However, big things are always made up of small things. With these Pearl Harbor facts, learn more about the details of the Pearl Harbor attack and what came before and after.
The date of the Pearl Harbor attack depends on the timezone.
In Hawaii and the rest of the USA, the attack took place on the morning of December 7, 1941. This is the date used by historians today. In Japan and the rest of Asia, though, the attack actually took place on the morning of December 8, 1941.
Japan codenamed the attack on Pearl Harbor as Operation Z.
This refers to the Z flag, a signal flag used internationally to represent the letter Z when using flags to communicate at sea. In Japan, the Z flag has historical symbolism going back to the Russo-Japanese War of 1904 to 1905. Admiral Heihachiro Togo used the Z flag as his personal standard during the Battle of Tsushima, where Japan defeated Russia.
This led the Z flag to become a symbol of victory in Japan, so the Imperial Japanese Navy (IJN) used the letter Z as part of the codename for the attack on Pearl Harbor. To them, the attack would ensure victory against the USA, so it only seemed fitting to use such a codename. Definitely one for ironic Pearl Harbor facts.
Japan didn’t actually want to go to war with the United States.
At the time, Japan actually aimed their ambitions at China, starting with the puppet state Manchukuo’s founding in 1931. The Second Sino-Japanese War followed in 1937, which had become stalemated by 1941.
However, the USA saw Japanese expansion into China against its interests and responded with economic sanctions against Japan. Over the years, the US aimed at pressuring Japan into stopping the war in China without actually having to go to war themselves.
The USA drew the line at Japan’s occupation of French Indochina in 1940.
In June 1940, Germany crushed France in what historians call the Fall of France. As a German ally, Japan then demanded that the new, Vichy French government allow Japanese troops to occupy their colonies in French Indochina. Not wanting to fight Japan, the Vichy French agreed. This allowed Japan to deploy aircraft over Southern China, and to cut off American support that once passed through French Indochina to China.
US President Franklin Delano Roosevelt saw this as unacceptable, and immediately froze all of Japan’s assets in the USA. He also stopped all exports of oil and metal to Japan, in hopes of getting the Japanese war machine to come crashing to a halt. It also caused the Japanese economy to struggle even more. Roosevelt expected all of those to finally bring Japan to the table, and end the war in China. Again, an ironic example of Pearl Harbor Facts.
Japan tried to negotiate with the USA afterward.
Unfortunately, Japan didn’t want to stop the war in China. Both the Japanese government and the Imperial Japanese Army (IJA) didn’t want to be seen backing down from foreign pressure. They also didn’t want to waste all the effort and lives spent fighting for years in China.
However, the US would not accept these terms. Specifically, Japan had to end the war in China and remove all its troops from both China and French Indochina. Only then would the USA lift the sanctions on Japan. Unable to accept the American terms, and with the economy starting to collapse, the Japanese government made the decision to expand the war.
Admiral Yamamoto considered the attack on Pearl Harbor a gamble.
Despite his involvement in planning the attack, Admiral Yamamoto was very concerned about war with the USA. He had studied at Harvard University, and even served as part of the Japanese military attache in Washington D.C. In that time, he’d seen for himself the overwhelming difference between Japan and the USA’s industrial capacity.
As such, he warned his fellow officers and the Japanese government that the attack on Pearl Harbor would only guarantee Japan 6 months of victory at sea. If the USA did not make peace in those 6 months, then they would overwhelm Japan afterward.
The attack on Pearl Harbor was only part of a bigger plan.
There’s an unsurprising example of Pearl Harbor Facts. The plan involved an attack into what the IJN called the Southern Resource Area, which included the whole of Southeast Asia. Once Pearl Harbor had taken the US Navy (USN) out of play, Japan would launch a full-scale invasion of the region. Taking the Philippines would remove naval and air bases the USA and the rest of the Allies could use against Japan.
This same reasoning also applied to the nearby American islands of Wake and Guam. Taking British Malaya would secure Japan’s metal needs, and taking the Dutch East Indies would secure Japan’s need for oil. British Burma offered more oil and metal, while the already-occupied French Indochina secured Japanese demand for rubber. The Japanese also expected those territories to provide food for their country as well as their fleet and armies.
Japan made extensive preparations for the attack.
These included scale models of Pearl Harbor and its facilities, as well as the ships present. Spies in Hawaii provided the geographic details, as well as up to date information on the ships in the harbor.
The Japanese also included the American airfields on the island in their preparations. Starting in April 1941, pilots and other officers used those models and information to familiarize themselves with their targets and to practice the attack. Talk about attention to detail, as we see it here, at Pearl Harbor Facts.
The shallow water of Pearl Harbor presented problems for Japan.
Specifically, the torpedoes carried by their planes wouldn’t have worked in the shallow waters. This didn’t last long, though, as the Japanese simply modified their torpedoes to adjust for the expected battlefield. There was also another problem that Japan never expected, and which they only realized after the attack.
Specifically, sinking the US Pacific Fleet’s ships in shallow water next to their main naval base meant the Americans could easily salvage and even repair them. It took time, but by the end of the war, most ships sunk at Pearl Harbor had rejoined the fight.
Japanese pilots received orders to prioritize their targets in the attack.
Japanese pilots targeted capital ships like aircraft carriers and battleships first. Only once those had sunk could they switch their targets to smaller ships, like cruisers and destroyers.
6 aircraft carriers made up the core of the First Air Fleet.
They were Akagi, Hiryuu, Kaga, Shoukaku, Souryuu, and Zuikaku. Akagi and Kaga were the oldest, and were originally designed as battleships but were instead completed as aircraft carriers. Akagi shared its name with Mount Akagi, while Kaga shared its name with pre-modern Japan’s Kaga Province.
In contrast, the other aircraft carriers were all designed and completed as aircraft carriers. Their names also have unique meanings. Hiryuu means flying dragon. Shoukaku means soaring crane. Souryuu means blue-green dragon. And Zuikaku means auspicious crane. Talk about poetic examples of Pearl Harbor facts.
Japan used 3 different models of carrier aircraft during the attack on Pearl Harbor.
A6M Zeros made up the fighter wings of the First Air Fleet. Fast and very agile, they stayed in service until the end of the war, and historians consider them the best carrier-based fighter in WWII until 1943. D3A Vals made up the First Air Fleet’s dive-bombers, and like the Zero, the Val served until the end of the war.
An old model by 1941, they also went down in history as the Axis plane to sink the most Allied warships in the war. Finally, B5N Kates made up the First Air Fleet’s torpedo bombers. Like the Val, the Kate was already old in 1941 but stayed the IJN’s torpedo bomber until the end of the war.
Some Kate torpedo planes received special weapons for the attack on Pearl Harbor.
They received this role instead of the Val dive-bomber because the Kate could carry heavier payloads. Specifically, a Val could carry only up to 250 kg worth of bombs, while the Kate was specifically designed to carry up to 800 kg, as torpedoes were both bigger and heavier than bombs.
So for the Pearl Harbor attack, some Kates carried special 800 kg bombs that were actually modified 14-inch armor-piercing battleship shells.
The First Air Fleet made a great effort to preserve secrecy.
Most importantly, they completely refrained from using radios while traveling from Japan to Hawaii. This kept the USA from picking up any radio transmissions that could give the Japanese away. While this meant that there wasn’t any contact between the fleet and Japan during their trip, contact remained between the fleet’s ships.
At sea, they used signal flags or a combination of spotlights and Morse Code to communicate instead of radio. In addition to complete radio silence, the First Air Fleet also approached Hawaii from behind a storm front. This kept the USN’s patrol planes from flying over and finding the First Air Fleet. Now there’s one of the Pearl Harbor facts that show the importance of attention to detail.
The First Air Fleet sent scout planes ahead of the attack.
They flew over Pearl Harbor before sunrise and were even spotted by several people. At the time, though, Pearl Harbor didn’t have a no-fly zone over it, and civilians regularly flew over the base to take in the sights. As such, no one thought much of the planes flying overhead.
It was then that the Japanese broke radio silence, informing Admiral Nagumo of the US Pacific Fleet’s presence. They also warned the admiral that none of the American aircraft carriers were at Pearl Harbor. Despite the aircraft carriers’ absence, Admiral Nagumo decided to continue the attack regardless.
None of the US Pacific Fleet’s aircraft carriers were at Pearl Harbor during the attack.
Both USS Enterprise and USS Lexington were at sea during the attack, while USS Saratoga was at San Diego. USS Enterprise was actually close enough to send several planes to help Pearl Harbor, though they didn’t do much good, in the face of superior Japanese numbers.
Japan actually declared war before the attack on Pearl Harbor began.
The Japanese government actually wanted to delay making the declaration until after the attack, to preserve the surprise. Admiral Yamamoto pushed for the opposite, as he knew attacking before declaring war would only make the Americans see it as a sneak attack and make them even angrier.
In particular, he pushed for the attack to happen at least 30 minutes after the US government had received a Declaration of War. However, delays at the Japanese Embassy caused a delay of an hour in its delivery to the US government. As Admiral Yamamoto predicted, the USA saw the attack as a sneak attack and became even angrier as a result.
American codebreakers received the Japanese declaration of war at the same time as the embassy.
However, inter-service rivalries between the US Army and Navy delayed any warnings getting sent. Ambiguities in the wording of the Japanese Declaration of War also caused further delay. All these contributed to postwar conspiracy theories that President Roosevelt let the Japanese attack Pearl Harbor, in order to get an excuse to bring America into WWII.
The Americans were already on alert when the attack began.
The Americans knew that the diplomatic situation with Japan meant that war could break out at any time. But they expected Japan to strike at the Philippines first, and not at Pearl Harbor. And while Pearl Harbor was on alert, their priority was against sabotage and not a full-scale attack by the IJN.
The American focus on preventing sabotage proved disastrous for their ground-based planes.
The Americans lined up their planes on the runways, instead of keeping them inside armored hangars. They reasoned this made it easier for patrols to protect them from saboteurs. Unfortunately, this meant the Japanese planes could just shoot them up in the open when the attack began, lined up as they were in straight lines on the ground.
The American focus on preventing sabotage also proved disastrous for their anti-aircraft defenses.
Anti-aircraft (AA) guns stayed locked up inside the armories, in order to protect them from saboteurs. Ammunition was also kept separate, again to protect them from saboteurs. But when the attack came, this meant that the AA guns and their ammunition first needed to come out of storage. This, in turn, delayed the American ability to fight back against the attacking Japanese.
American radar actually picked up the incoming Japanese.
At the time, however, radar and its use were all new and recent innovations. Procedures for confirming and responding to radar contacts were still under development. Pearl Harbor was also expecting several B-17 heavy bombers to arrive from the mainland. This led the on-duty personnel to dismiss the incoming contacts instead of sending a warning.
The attack on Pearl Harbor was on a Sunday.
This proved a mixed factor for both the Japanese and the Americans. For the Japanese, this meant that the Americans were more relaxed than on any other day, and increasing the effect of surprise. It also meant that the sense of sneak attack was stronger, making the backlash.
For the Americans, this also meant that many officers were not on the ships or the airfields during the attack. This, in turn, ensured their survival in the attack and allowed them to fight another day.
Commander Mitsuo Fuchida gave the famous “tora, tora, tora” at the start of the attack.
In Japanese, tora means tiger. Commander Fuchida’s phrase was actually a codeword, signaling the beginning of the attack, and that they had achieved complete surprise.
The Vals of the 1st wave had separate targets from the Vals of the 2nd wave.
The 1st wave’s Vals targeted Ford Island and Wheeler Field. Ford Island’s airfield was the closest to Pearl Harbor, and planes from there could respond the quickest to the Japanese. This, naturally made them a priority target. Wheeler Field, though, was the biggest airfield in Hawaii. Naturally, this also made this a priority target for the Japanese.
Zeros targeted the smaller airfields in Hawaii.
This allowed the Vals to concentrate on the most important targets, though many Zeros also helped attack Ford Island and Wheeler Field. Airfields targeted by Zeros include Barber’s Point, Hickam Field, and Kaneohe.
The Vals of the 2nd wave focused on warships rather than airships.
Kates armed with heavy bombs instead finished off the airfields already attacked by the 1st wave’s Vals. Zeros helped them in this, while the Vals dive-bombed any ship leftover from the 1st wave’s attacks.
The Japanese missed 1 airfield.
Here’s a surprising example of Pearl Harbor facts, especially Japan’s attention to detail when planning their attack. This was Haleiwa Fighter Strip, a small airfield used for emergency landings. Its lack of importance led to Japan ignoring it when planning for the attack.
This meant that planes from Haleiwa managed to fight in the air, such as P-40 Warhawks piloted by George Welch and Kenneth Taylor. Welch shot down 4 planes, and Taylor shot down 2 planes. Both of them received the Distinguished Service Cross for their valor in the battle against overwhelming odds.
USS Arizona suffered the worst damage out of any ship in Pearl Harbor.
The first wave targeted the battleship, with Kates dropping their special, 800 kg bombs from around 3 km in the air. The first 4 bombs caused only moderate damage. Then at 8:06, a bomb punched through the armored deck near Turret II and exploded next to the magazine.
This set off the gunpowder and shells kept inside and wrecked Arizona’s interior. It also blew the ship in half and caused the wreck to sink immediately. Out of Arizona’s crew of 1,512, 1,177 died, around half of the American casualties in the attack.
The highest-ranking casualty of Pearl Harbor was from the USS Arizona.
This was Rear Admiral Isaac C. Kidd, who had chosen the battleship as his flagship and of Battleship Division 1. Survivor testimony claims the admiral rushed to the bridge once the battle began, and died at his post when the battleship exploded. As the admiral’s body was never recovered, he remains listed as missing in action to this day.
The USA never attempted to repair the USS Arizona.
In 1942, the USN removed the parts of the ship sticking out of the water, and from 1943 to 1944, they also removed the ship’s guns. Despite her sunk sake, the USN still considers Arizona a fully-commissioned naval vessel. This is one of the ways in which they honor the dead of the ship from Pearl Harbor.
The USA built the Arizona Memorial in 1962.
A solemn, and well-deserved example of Pearl Harbor Facts without a doubt. They built it to look like a bridge, finished in white, and floating above the wreck without touching. The interior commemorates both the dead of Arizona and the rest of the attack. Accessible only by boat, the memorial can accommodate up to 200 people at a time. Over 2 million people visit the memorial every year to pay their respects.
Oil slowly leaks out of the USS Arizona to this day.
Fuel oil specifically, with about 2.18 liters leaking out into the surrounding waters per day. Visitors can actually see the oil as a slick on the water’s surface around the Arizona Memorial. Experts estimate another 2 million liters of oil left in the wreck’s fuel tanks.
Given the ship’s rusted condition, the collapse of those tanks is naturally a major concern. However, the ship’s state makes it too dangerous to try and pump the oil out, as that might actually cause the tanks to collapse. Today, the USN is currently studying a way to keep the tanks from collapsing, as well as stopping the leaking of oil.
The USS Oklahoma suffered almost as much damage from the attack.
Here’s another grim example of Pearl Harbor facts. Five torpedoes hit the battleship one after another, all on the left side. This flooded the port side of the battleship, causing Oklahoma to capsize and trapping hundreds of men inside.
Rescue operations continued into the night, made complicated by the risk of igniting leaking oil. All in all, 429 officers and enlisted died from among the battleship’s crew. It’s not known how many more crew died trapped inside the ship.
Like the USS Arizona, the USN never repaired the USS Oklahoma.
The damage was just too great. The Americans salvaged the superstructure in 1942 and removed the guns from 1943 to 1944. After the war, the wreck was then sold for scrap in 1946 but sank in deep water while on tow to the mainland.
The other battleships sunk at Pearl Harbor all returned to duty over the following years.
Of course, it depended on how badly damaged the battleships were. USS Maryland, Nevada, and Tennessee all returned to service in 1942. Both USS California and West Virginia returned to service in 1944. The USS Pennsylvania only suffered minor damage, and needing few repairs, fought in the war from the very beginning.
The Japanese plan originally called for 3 attack waves.
As planned, the 3rd wave of the attack would focus on infrastructure. These included the naval yard, the military headquarters, the oil depot, and the submarine pens. But Admiral Nagumo canceled the 3rd wave despite other officers willing to launch it, and decided to set sail back to Japan.
Admiral Nagumo had several reasons to cancel the 3rd wave.
One of those was fuel. If the First Air Fleet stayed for much longer near Hawaii, they’d have to abandon several destroyers on the way home once they ran out of fuel. A second reason was improving American defenses. By the time the 2nd wave began its attack, the Americans had managed to bring out their AA guns.
In fact, statistics show that the 2nd wave suffered 20 losses compared to 9 in the first wave, all from AA guns. Another 74 suffered damage from AA guns. Finally, Admiral Nagumo suspected the US aircraft carriers could launch a surprise attack of their own, and catch his planes in the air low on fuel and ammunition. Talk about cutting your losses, as we see it here, at Pearl Harbor Facts.
The 3rd wave’s cancelation had major effects.
First, with the fuel depot intact, Pearl Harbor could still, in fact, support a fleet. Admiral Chester Nimitz even admitted after the war that if Japan had destroyed the fuel depot, the USN couldn’t have launched offensive actions for a full year instead of just 6 months. He also claimed it would have extended the war for another 2 years. Sparing the submarine pens also came back to haunt Japan.
The basement actually housed the USN’s codebreaking facilities. In 1942, their achievement in cracking the Japanese naval communications directly contributed to the US victory at Midway. All in all, another surprising example of Pearl Harbor Facts, again considering Japan’s attention to detail when planning their attack.
Historians also question how effective the 3rd wave could have been.
In particular, they question just how badly the Japanese could have hit the naval yard. The American experience in the bombing campaigns against Japan and Germany found that naval yards and other major infrastructures proved surprisingly resistant to bombing.
Even specially-designed, 500 kg bunker-buster bombs needed constant bombing to have any real effect. Otherwise, enemy engineers could repair any damage in days. Historians also question the vulnerability of the fuel depot, thanks to the difficulty in actually burning fuel oil.
President Roosevelt made the Infamy Speech after Pearl Harbor.
This is where the famous “day of infamy” reference comes from. President Roosevelt made the speech in front of the US Congress on December 8, 1941, the day after the Pearl Harbor attack. He referenced how Japan and the USA had actually still discussed avoiding war right up until the attack, and thus the attack was nothing more than betrayal and a stab in the back by the Japanese. The speech was quite short, only 7 minutes long, but it went down in history as one of President Roosevelt’s most memorable.
America declared war against only Japan.
The US Congress issued the Declaration of War on December 8, 1941. They did it only an hour after President Roosevelt made his famous speech. After the Americans declared war on Japan, Japan’s allies Germany and Italy also declared war on the USA.
The Americans kept a grudge for the Pearl Harbor attack.
The attack also didn’t just involve America in WWII. Without an attack on Pearl Harbor, historians agree that even if America had joined the war, it would have divided the American people. Some would have refused to support the war and continued to push for America to stay neutral. It might even have enough to keep America from pushing for unconditional surrender.
Instead, the perception of a Japanese sneak attack united America behind the war, with the determination to see it through to complete victory.
Admiral Yamamoto became a personal target for the Americans.
Despite not having personally commanded the attack, Admiral Yamamoto’s key role in its planning made his name mud for the Americans. When American codebreakers discovered the course the plane the admiral was on in 1943, Admiral Nimitz personally gave the order to take him down.
P-38 Lightnings based on Guadalcanal launched to intercept Admiral Yamamoto as he left Rabaul, and shot him down before he could reach his destination. The Americans even codenamed the mission as Operation Vengeance.
Admiral Yamamoto’s warning about 6 months proved prophetic.
Japan achieved all its goals in the 6 months after Pearl Harbor. With the USN out of the picture, the Empire of Japan quickly overran all of SE Asia. Even the heroic resistance of Bataan and Corregidor in the Philippines could only slow, not stop the Japanese advance. But as early as May 1942, 5 months after Pearl Harbor, the Japanese began running into trouble from the Americans.
In the Battle of the Coral Sea, despite a victory against the USA, Japanese losses kept them from using the victory at sea to win on land in New Guinea. And then in June 1942, at the Battle of Midway, 6 months after Pearl Harbor won a major victory. All 4 Japanese carriers sunk in that battle fought at Pearl Harbor: Akagi, Hiryuu, Kaga, and Souryuu. After that battle, the Japanese could only stay on the defensive, and the Americans steadily began pushing them back.
Pearl Harbor’s targets also proved misguided.
Japan prioritized sinking the American battleships at Pearl Harbor. Only Yamamoto really appreciated the lack of the American aircraft carriers at Pearl Harbor. Other Japanese admirals saw their absence as meaningless, as they saw battleships as the backbone of a modern navy. To them, aircraft carriers only had use to provide support and additional firepower.
In the end, Yamamoto proved right again, as aircraft carriers and submarines spearheaded American’s victory against Japan. Aircraft carriers won every battle at sea against Japan, while submarines kept resources from getting to Japan’s factories. Battleships only proved useful in supporting ground invasions by US marines and shooting down attacking planes. In the end, aircraft carriers proved themselves the future and battleships as relics of the past.
America actually prioritized Germany in WWII.
This, despite the fact that Japan attacked America first and brought them into the war. America’s leaders decided on the Germany First strategy because they saw Germany as the bigger threat. Germany had more resources, had a bigger industrial base, and better chances of winning.
If Germany could defeat the Soviet Union, then it was actually possible they could stalemate Britain and the USA. Long enough to force their public to grow tired of the war, and pressure the government to end it. Japan had no such chance of doing the same to Britain and the USA.
America already began winning the war even with a Germany First strategy.
Despite their secondary priority, American forces in the Pacific already began winning the war in 1942. We’ve already mentioned the Coral Sea and Midway. Then in 1943, US troops held Guadalcanal against the Japanese and kept them from using it to secure their positions in New Guinea. And in 1944, the USN destroyed the IJN and liberated the Philippines through the Marianas campaign.
The Marianas Campaign saw the beginning of the end for Japan.
With control of the North Pacific, American bombers could now reach Japan itself. Daily bombing raids began, aimed at destroying Japan’s industry and breaking the Japanese people’s will to fight. The USN also began taking the outer islands of the Japanese archipelago, like Iwo Jima and Okinawa. They did so with the goal of using those islands to launch an invasion of the Japanese Home Islands in 1945.
Japan finally surrendered on September 02, 1945.
By then, the Japanese faced more than just an American invasion of Japan. The Soviets had already invaded their Manchurian colony, and the IJA in China could not return to defend Japan. Not with the IJN already destroyed, and American submarines had cut off all shipments of food and raw materials.
Their allies in Germany and Italy had already surrendered, and constant bombing had destroyed Japan’s industry. Then came the nuclear attacks, with Hiroshima destroyed on August 6, and Nagasaki on August 9. Faced with complete destruction, and given a quiet assurance that the Emperor would not have to abdicate, Japan surrendered. With that, WWII finally came to an end.