Indochina was a French-administered colony in Southeast Asia comprising the present-day nations Vietnam, Laos, and Cambodia. On July 20, 1941, Japanese troops entered the region and quickly occupied the entire area. Japan justified the occupation as necessary in order to deny resources to the Chinese resistance. However, Indochina also provided Japan with a convenient base for launching attacks against other countries and territories in the region, including Singapore and the Dutch East Indies. Both the United States and Britain saw this move as a threat and a clear indication of Japan’s intention to continue its expansion throughout the Pacific Rim. The two countries expressed their disapproval by freezing Japanese bank accounts.
As early as January 1941, Admiral Yamamoto Isoroku developed a plan for attacking the U.S. fleet at Pearl Harbor and carried out training exercises to prepare specifically for such an attack. In October, the Japanese emperor, Hirohito, gave his general approval for action against the United States and, on November 8, approved the specific Pearl Harbor attack plan.
On November 25–26, the Japanese fleet set sail from Japan, unseen by U.S. spies. Even then, however, some Japanese officials disapproved of the plan, and it continued to be debated heatedly. By December 1, all discussion had ended, and Hirohito ordered the plan to proceed. Japan’s goal was to make a permanent end to Western interference in its affairs by obliterating the U.S. and British military capabilities in the Pacific.
On the morning of December 7, 1941, a fleet of six aircraft carriers, twenty-five submarines, and nearly three dozen additional support ships was sitting 200 miles north of the Hawaiian island of Oahu—in the open sea, far beyond the line of sight of any U.S. forces. The first wave of Japanese planes numbered more than 180. Although U.S. radar operators saw the massive formation nearly a full hour before the attack began, they raised no alarm, because they mistook the planes for a group of U.S. bombers expected to arrive from California around the same time. This mistake happened in spite of the fact that the planes seen on the radar were coming from the wrong direction and were much more numerous than the expected bomber fleet.
The first wave arrived at the U.S. Navy base at Pearl Harbor at 7:55a.m. and achieved complete surprise; only nine Japanese planes were lost. The primary targets were major U.S. warships, most of which were docked close together in neat lines. These included eight of the nine battleships in the U.S. Pacific Fleet, along with several dozen other warships. The Japanese also targeted six nearby military airfields. A second attack wave of more than 160 planes followed just over an hour later. By this time, the Americans were well alerted and managed to bring down twenty Japanese planes.
In all, the attack on Pearl Harbor killed 2,402 Americans, destroyed five battleships completely, put three more out of commission, sank or seriously damaged at least eleven other warships, and destroyed nearly more than 180 aircraft on the ground. The only good luck the U.S. Navy had was that none of its aircraft carriers were in port at the time and that the Japanese bombers failed to hit the large fuel reserves in the area.