December 7, 1941 — a day that will live in infamy. The attack, conducted by the Japanese Navy against the United States’ Naval Base at Pearl Harbor, Hawaii, sank four U.S. Navy battleships (two of which were raised and returned to service later in the war) and damaged four more. The Japanese also sank or damaged three cruises, three destroyers, and one minelayer, destroyed 188 aircraft, and caused personnel losses of 2,402 killed and 1,282 wounded. The attack consisted of two aerial attack waves totaling 353 aircraft, launched from six Japanese aircraft carriers, and was called ‘Hawaii Operation Z’ by the Japanese Imperial General Headquarters. Japanese losses were minimal, at 29 aircraft and five midget submarines, with 65 servicemen killed or wounded.
War between Japan and the United States had been a possibility each nation had been aware of (and developed contingency plans for) since the 1920s, though tensions did not begin to grow seriously until Japan’s 1931 invasion of Manchuria. Over the next decade, Japan continued to expand into China, leading to all out war in 1937. The transfer of the U.S. Pacific Fleet from its previous base in San Diego to its new base in Pearl Harbor was seen by the Japanese military as the U.S. readying itself for a potential conflict between the two countries.
While the attack ultimately took place before a formal declaration of war by Japan, Admiral Yamamoto originally stipulated the attack should not commence until thirty minutes after Japan had informed the United States he considered the peace negotiations at an end. In this way, the Japanese tried both to uphold the conventions of war as well as achieving surprise. Despite these intentions, the attack had already begun when the 5,000-word notification was delivered. The declaration of war was printed in the front page of Japan’s newspapers in the evening edition on December 8.