Pearl Harbor (World War II)

For the geographic area, see Pearl Harbor

On December 7, 1941, units of the Imperial Japanese Navy conducted air and submarine operations against American forces in the Battle of Pearl Harbor. This battle was a key element in the major Japanese escalation of what they call the Pacific War.

While the United States had intelligence suggesting a high probability of Japanese attacks in December 1941, and some specific information that either did not reach the Pearl Harbor commanders, Admiral Husband Kimmel (Navy) or Lieutenant General Walter Short (Army), the attack was a tactical surprise.

Few battles, and the circumstances leading to them, have been studied as extensively as this one. Many concepts of the discipline of intelligence and warning resulted from this action.

Japanese operational concept

Japan opened World War Two in the Pacific with an offensive principally based on their Strike-South doctrine, seeking resources in Southeast Asia. Nevertheless, they believed they had to deter U.S. forces from intervening.

U.S. intelligence and planning

Threat assessment

Sabotage vs. air attack

Short was convinced that the major threat to his aircraft was sabotage by residents of Japanese ancestry, so he had them parked in close formation for ease in guarding them against ground attack. This made them dense targets for strafing and bombing.

Implications of the Battle of Taranto

In 1940, the Royal Navy, at the Battle of Taranto, delivered a devastating night attack, by torpedo aircraft, to battleships in a harbor. The U.S. Navy, in spite of knowing the details of that attack, still believed its ships were safe from aerial torpedoes in a harbor, although Taranto was as shallow as Pearl.

The attack

Preliminaries

Japanese torpedo bomber taking off to attack Pearl Harbor

First wave air attack

Japanese perspective approaching Battleship Row

The picture, taken from a Japanese aircraft, shows USS Nevada (BB-36) with flag raised at stern; USS Arizona (BB-39) with repair ship USS Vestal (AR-4) outboard; Tennessee (BB-43) with West Virginia (BB-48) outboard; USS Maryland (BB-46) with USS Oklahoma (BB-37) outboard; USS Neosho (AO-23) and USS California (BB-44).

West Virginia, Oklahoma and California have been torpedoed, as marked by ripples and spreading oil, and the first two are listing to port. Torpedo drop splashes and running tracks are visible at left and center. White smoke in the distance is from Hickam Field. Grey smoke in the center middle distance is from the torpedoed USS Helena (CL-50),