A Japanese carrier force attacked the US naval base at Pearl Harbor, O'ahu, Hawaii, on 7 December 1941 and so brought the United States into the Second World War (1939-45). The surprise attack, made before war was officially declared, caused over 3,500 casualties and destroyed or seriously damaged 18 ships, including eight battleships. Crucially, the US aircraft carriers were not in Hawaii at the time, and vital supply dumps and repair facilities were left intact. As a consequence, the US Navy was eventually able to recover. Japan, having taken over most of Southeast Asia in 1942, was gradually pinned back during the Pacific War to hold only its own islands. Japan surrendered in August 1945 following the dropping of two atomic bombs. The US had gained the ultimate revenge.
The Japanese Empire
By late 1941, Japan's military government had already occupied Manchuria, Formosa (Taiwan), Korea, parts of coastal China, and the north of French Indo-China (which included what is today Laos, Cambodia, and parts of Thailand). A setback to Japanese expansion came in the summer of 1939 when its forces were defeated by those of the USSR in the border region between Manchuria and Outer Mongolia. The Japanese army suffered 18,000 casualties at the Battle of Nomunhan (aka Khalkhin Gol). This defeat gave the Japanese navy one more argument in its favour that the Pacific should be Japan's next area of conquest.
The expansion of Japan's military required massive quantities of raw materials which Japan simply did not have. Nor could the Japanese buy these resources. A US embargo on oil, gasoline, iron ore, coal, copper, steel, lead, tin, rubber, and nickel was imposed in order to induce Japan to withdraw from China and protect US interests in places like the Philippines. British Malaya and the Dutch East Indies (Indonesia) also restricted oil sales to Japan. Japanese financial assets in US banks were frozen, severely limiting Japan's ability to buy oil. By mid-1941, Japan felt obliged to acquire the resources it needed through conquest.
In April 1941, a Soviet-Japanese non-aggression pact was signed, which permitted Japan to concentrate on its growing empire to the south. In July 1941, Japan attacked southern Indo-China. On 1 December 1941, the Japanese government decided it would declare war on the United States, Britain, and the Netherlands. The Japanese military government felt that, sooner or later, these states would declare war on Japan anyway if it continued its expansion in the Pacific, particularly if it attacked the oil-rich areas of British Malaya and the Dutch East Indies. An attack on the US's allies Britain and the Netherlands would surely provoke the US into finally entering the war.
A preemptive strike on the US Navy, it was hoped, would allow Japan to dominate this theatre of WWII. The destruction of as many US ships as possible would be essential since the Japanese Navy could not compete with the numerically larger US Navy and the much more powerful economy of the US in the long term. An attack plan had been devised by Admiral Yamamoto Isoroku (1884-1943), Commander-in-Chief of the Combined Fleet. A large aircraft carrier group would sail secretly to Pearl Harbor in Hawaii, home of the US Pacific Fleet. Japanese planes would then use newly developed torpedoes to sink US aircraft carriers and battleships while they were still in port.
The Hawaiian Naval Base
The US had possessed the Hawaiian islands since 1898, but the naval base had only been created at the beginning of 1940. The Pacific Fleet at Pearl Harbor, which was composed of almost 100 ships, was commanded by Rear-Admiral Husband E. Kimmel (1882-1968). The other major US presence in the Pacific was in the Philippines, considered the most likely target of Japanese aggression. This belief, a perfectly reasonable one, was based on geography. The Philippine Islands were just 200 miles (320 km) from Japan's bases on Formosa, whereas Pearl Harbor was some 3,400 miles (5,500 km) from Japan. The US military was also not aware that the Japanese had developed a torpedo capable of operating in shallow waters, and so they believed Pearl Harbor could not be attacked by aircraft. For this reason, the harbour was not given protective anti-torpedo nets. It was widely believed that if the base were ever attacked, this would come in the form of sabotage, not a direct battle.
The Japanese Carrier Group
The Japanese attack group was commanded by Vice-Admiral Chuichi Nagumo (1887-1944). It consisted of six aircraft carriers (two of which had been converted from a battleship and a cruiser, respectively), two battleships, two heavy cruisers, one light cruiser, and a protective escort of nine destroyers, eight fuel tankers, three submarines, and several other support ships. The aircraft were commanded by Captain Mitsuo Fuchida (1902-1976), who himself flew in the first attack wave.
The ships of the carrier group left their bases at Kure in the second and third week of November. The ships maintained strict radio silence to avoid detection by enemy intelligence listeners and avoided the main shipping lanes. The group was under orders to board or sink any vessel they came across that could report their progress across the Pacific.
Kimmel was sending out reconnaissance aircraft from Pearl Harbor through the first week of December, but he did not have sufficient resources to send patrols in all directions. Kimmel concentrated on an arc of reconnaissance which covered the Marshall Islands to the southwest, which were the closest Japanese territory. The Japanese force, though, was actually approaching Hawaii from the north.
US military intelligence, which had been intercepting and deciphering Japanese coded messages for some time, was aware that some sort of Japanese operation was underway. Pearl Harbor was even mentioned in these coded messages, notably in a communication to the Japanese consul in Honolulu to have spies identify which ships were in which part of the harbour, but this information was never passed on to the base in Hawaii.
Still undetected and still 275 miles (450 km) from Hawaii, the Japanese aircraft left their carriers at 6:00 a.m. on Sunday 7 December. Japanese diplomats had intended to present Washington with a formal declaration of war at 1 p.m. that day, but a delay, probably down to the translation office not realising the matter was urgent, meant the declaration was made after news of the attack had already reached the US president.
The Attack
The first attack wave consisted of 40 torpedo bombers, 51 dive-bombers, and 43 fighter planes. A second, larger attack wave followed, this time with 54 bombers, 78 dive-bombers, and 36 fighters. At the same time, 16 submarines approached the harbour, five of them carrying midget submarines. One of these submarines had been spotted at 3:45 a.m., but nobody of any consequence was informed until it was sunk three hours later by a destroyer patrolling the approach to Pearl Harbor. As it turned out, the submarine element of the attack was a total failure. The devastating damage would come from the air. Between 6:45 and 7:00 a.m., US radar units picked up the first Japanese aircraft. Again, the report was ignored for lack of precision over the identity of these aircraft since a number of US B-17 bombers were expected in the area that morning.
As a result of the belief that Pearl Harbor would not be attacked by air, the base's anti-aircraft guns did not have sufficient supplies of ammunition. In addition, the island's army commander, Lt-General Walter Short (1880-1949), had deliberately bunched up his aircraft on the ground and left them unarmed in order to better safeguard them against acts of sabotage. Similarly, the naval defences were unprepared for an air attack. Only one in four of the navy's machine guns were manned, and all of the spare ammunition was locked away. As the Japanese aircraft approached the harbour that Sunday, one-third of the naval captains and a large number of other officers were ashore.
The first Japanese low-level torpedo-planes and dive-bombers hit the ships and the various airfields around 7:55 a.m. There was no response at all from the US defences. Fuchida was able to send the radio signal Tora, tora, tora ("Tiger, tiger, tiger") back to Nagumo, the code that complete surprise had been achieved.
The measure of surprise is indicated by the fact that many people at Pearl Harbor could not believe the attack was happening even when the bombs were falling. Lieutenant Ken Murray, a US staff officer, remembers:
My first knowledge of the attack was when I was awakened by the sound of bombs dropping and the roaring of aircraft all around us. I ran out and saw immediately that they were Japanese planes and there was this fellow standing next to me who said, 'Boy, it certainly looks real, doesn't it?'…I happened to be standing next to the Commander-in-Chief, Admiral Kimmel, and we were glumly watching the havoc that was going on. Suddenly he reached up and tore off his four-star shoulder boards, which indicated his rank…
(Holmes, 200)
Targets which Japanese military intelligence had given the pilots were easily picked out in the clear weather. The pilots had been ordered not to drop their torpedoes unless certain of a hit. Around 8:25 a.m., Japanese conventional bombers dropped their loads from high altitude. The second wave of torpedo and dive-bombers then struck between 8:55 am and 9:15 a.m. This second wave was met with fierce fire from anti-aircraft guns and a handful of US fighters that had managed to get airborne in the chaos. The second attack wave also had to deal with much poorer visibility as huge clouds of smoke rose from the stricken warships. The attack was over by 9:45. Nagumo had taken the decision not to send in a planned third wave of aircraft in case of a counterattack from the missing aircraft carriers.
Death Toll & Damage Inflicted
The Japanese task force ultimately sank or seriously damaged 18 ships. Six battleships were sunk and the other two badly damaged. These giant vessels had been neatly lined up in 'Battleship Row.' The battleship Arizona was the scene of the greatest terror; its forward magazines had exploded, and 1,103 of the ship's crew died instantly or drowned as the broken ship sank. Eyewitness Marine Richard Fiske, serving on the USS West Virginia, remembers:
I saw the Arizona blow up and she just sort of rained sailors. I wasn't very scared at this particular time because I couldn't imagine that this was happening to us: it just wasn't real; it seemed like a nightmare. I didn't really comprehend the impact of it until afterwards when I swam ashore and realised, my God, we're at war.
(Holmes, 201-2)
Three destroyers, three cruisers, and four other ships were either sunk or badly damaged. 164 US aircraft were destroyed and another 128 damaged. 2,403 people, service personnel and civilians, were killed and another 1,178 people were wounded. The Japanese force lost just 29 aircraft and six submarines, most of which were easily replaceable minisubs. 64 Japanese servicemen were killed in the attack. The Japanese carrier group returned to Japan intact on 23 December.
The attack was a crushing blow, but crucially for future operations, the two US aircraft carriers, Enterprise and Lexington, were out on manoeuvres when the attack came. The Japanese had thought there would be four carriers to attack, but the Hornet and Yorktown were operating in the Atlantic Ocean in December. Another saving grace was the fact that the fleet's heavy cruisers were all out on manoeuvres, too.
The bases' fuel depots, which had some 4.5 million barrels, and ammunition stocks, the repair shops, dry docks, and submarine pens, had all survived the attack, and so Pearl Harbor could continue to operate. These targets could have been the objective of the abandoned third wave of aircraft. The fuel and repair capabilities would be badly needed since, thanks to the water being relatively shallow, all but three of the lost or damaged ships could be recovered and eventually returned to active service.
Pearl Harbor was a disaster for the US, but it could have been much worse. If the aircraft carriers had been sunk, the US Navy would have been obliged to retreat to the mainland USA. The attack was, then, a resounding tactical victory for Japan, but it was not a strategic one. The US Navy could fight on, and the psychological impact of what was regarded as a sneak attack galvanised US public opinion into wholeheartedly supporting the US entry into the war. Resolve was further stiffened when Germany and Italy declared war on the US on 11 December.
Aftermath
Six official investigations and one inquiry by Congress were made into the Pearl Harbor disaster to discover what had gone wrong. Kimmel and Short, both of whom resigned, were made the scapegoats at the time (but later were exonerated) when really interservice rivalries and communication cock-ups had done the damage. No convincing evidence has ever come to light that US officials had deliberately allowed the attack to happen in order to force the US into war. Neither is there evidence that British military intelligence knew of the attack before it happened. In short, the Japanese attack had been so audacious that nobody had imagined it possible before the event.
The Pearl Harbor attack was not the end but only the beginning of the Pacific War (called by the Japanese the Great East Asia War). Day two of this war also went well for Japan when a raid destroyed the majority of the 35 B-17 Flying Fortress aircraft belonging to the USAAF on Luzon Island in the Philippines. The response from the US was to declare war on Japan, President Roosevelt declaring to Congress: "Yesterday December 7 1941 – a date which will live in infamy" (Horner, 29).
Japan would win many more victories through 1942, creating a huge Japanese enclave across Southeast Asia that stretched from Manchuria to the Dutch East Indies north-to-south and Burma (Myanmar) to the Marshall Islands west-to-east. The war, though, was a fight Japan could not win in the longer term given the combined resources of the Allies, which proved to be far superior in personnel numbers, weapons output, and technology. Eventually pushed back to defend only its own islands, Japan's war ended with devastating consequences for the Japanese people when two atomic bombs were dropped on Hiroshima and Nagasaki in August 1945.
