Japan's attack on Pearl Harbor was the first step in the Southern Operation, an attempt to invade and conquer resource-rich Southeast Asia. By crippling American naval power in the Pacific, Japan hoped to consolidate and strengthen its hold on its conquests before the United States could rearm.
- 1931 Japan overruns Chinese Manchuria, quits League of Nations.
- Aug. 1937 Japanese troops attack Chinese city of Shanghai and face three months of fierce opposition from Chinese.
- July 1939 Japanese troops move into northern Indochina.
- Sept. 27, 1940 Japan signs the Tripartite Pact, aligning with Germany and Italy.
- Jan. 1941 Admiral Isoroku Yamamoto, who assumed command of the Japanese Combined Fleet in 1939, proposes an attack on Pearl Harbor. Preparation of attack plans begins in March.
- March 8, 1941 U.S. Congress approves the Lend-Lease Bill to provide aid to countries, including Great Britain and China, who are fighting the Axis countries.
- June 1941 Japan now occupies all of Indochina. In response, the U.S. freezes Japanese assets and cuts off oil exports to Japan on July 24.
- Aug. 1941 Japan negotiates with U.S. for removal of sanctions, but decides to go to war with U.S. and Great Britain if talks are not successful by October.
- Sept. 24, 1941 U.S. intercepts intelligence between Tokyo and the Japanese Consulate General in Honolulu, asking spies to report positions of U.S. ships at Pearl Harbor.
- Oct. 17. 1941 General Hideki Tojo, war minister and leader of military extremists, becomes Prime Minister of Japan.
- Nov. 5, 1941 Admiral Yamamoto orders the attack on Pearl Harbor.
- Nov. 26, 1941 The Japanese First Air Fleet leaves Japans Kurile Islands for Hawai'i. The fleet takes a route rarely used by merchant ships, and avoids radio transmissions to remain undetected.
- Dec. 6, 1941 In Washington D.C., U.S. President Franklin Roosevelt makes a final appeal to the Emperor of Japan for peace. There is no reply. Late this same day, the U.S. code-breaking service begins intercepting a 14-part Japanese message and deciphers the first 13 parts. The Americans believe a Japanese attack is imminent, most likely somewhere in Southeast Asia.
- Dec. 7, 1941 About 9 a.m. Washington D.C. time, U.S. officials decode the last part of the Japanese message, stating that diplomatic relations with the U.S. are to be broken off. About an hour later, another Japanese message is intercepted. It instructs the Japanese embassy to break off talks with the U.S. at 1 p.m. Washington time. The U.S. War Department then sends out an alert to Hawai'i military officials. Technical delays prevent the alert from arriving until noon Hawaii time, four hours after the attack has already begun.
- Pearl Harbor attacked. Almost at the same time, Japanese warplanes strike the Philippines and two U.S. islands: Wake and Guam, which are later occupied. The Japanese also invade Thailand and Malaya. Later that month, Japanese troops invade Burma and Hong Kong.
- Dec. 8, 1941 The United States and Britain declare war on Japan.
3:42 a.m.
The minesweeper Condor, on patrol near the entrance to Pearl Harbor, spots a submarine periscope 50 yards in the distance. The Condor notifies destroyer USS Ward via blinker-light.
6 a.m.
The Japanese attack force, located 230 miles north of O'ahu, turns its carriers into the wind to launch its first wave of planes. Pilots use a Honolulu radio station's music to reconfirm navigation. 200 miles south of O'ahu, the aircraft carrier USS Enterprise launches 18 aircraft to scout ahead and land at Ford Island around 8 a.m.
6:45 a.m.
The USS Ward fires on the submarine. The midget sub, struck at the waterline, appears to slow and sink. The Ward then drops depth charges on the craft. At 6:53, two coded messages are sent from the Ward to the 14th Naval Headquarters at Pearl Harbor Naval Station, saying it had "attacked, fired upon, and dropped depth charges upon submarine operating in a defensive sea area."
7:02 a.m.
A private at the Army's six-month-old Opana Mobile Radar Station spots a large contact on the radar screen: 50 or more aircraft on a bearing for O'ahu. The private calls the Fort Shafter information center, the hub of the radar network.
7:15 a.m.
At Pearl Harbor Naval Station, code clerks decode the destroyer Ward's message about the mystery sub. Adm. Husband E. Kimmel, commander in chief of the Pacific Fleet, decides to "wait for verification" of the report because there had been so many "false reports of submarines" recently. Japanese launch 168 aircraft for second attack wave.
7:20 a.m.
Army Lt. Kermit Tyler, who is in training at the radio-network operations center at Fort Shafter gets the Opana radar station report. The lieutenant believes that the radar had picked up a flight of U.S. B-17 Flying Fortress bombers heading from California to Hawai'i. He tells the men: "Don't worry about it."
7:40 a.m.
Japanese planes reach O'ahu's North Shore. As they near O'ahu, the attack commander hears a Honolulu weather report: "Clouds mostly over the mountains. Visibility good."
7:49 a.m.
Air-attack commander Mitsuo Fuchida, looking down on Pearl Harbor, sees no aircraft carriers, which the Japanese hoped to destroy and thus thwart U.S. retaliation. He orders his telegraph operator to tap out to, to, to: attack. Then other taps: to ra, to ra, to ra: attack, surprise achieved. Though not meant to have a double meaning, to ra is read by some Japanese pilots as tora tiger. According to a Japanese saying, "A tiger goes out 1,000 ri (2,000 miles) and returns without fail."
7:55 a.m.
At the Command Center on Ford Island, Cmdr. Logan C. Ramsey looks out a window and spots a low-flying plane dropping a bomb. Ramsey runs to a radio room and orders the telegraph operators to send out an uncoded message to every ship and base: AIR RAID ON PEARL HARBOR X THIS IS NOT DRILL. The coordinated attack begins as dive-bombers strike the Army Air Forces' Wheeler Field in Central O'ahu and Hickam Field near Ford Island's Battleship Row. Most U.S. planes, parked wingtip-to-wingtip in neat rows to guard against sabotage, are easy targets.
8 a.m.
Twelve B-17 Flying Fortresses have been ordered to the Philippines as part of a U.S. plan to bolster the Pacific forces. The first stop is O'ahu. Unaware that Japan is attacking, they prepare to land. Because they are unarmed to save weight the B-17s can only dodge Japanese fighters and U.S. antiaircraft gunfire. Most manage to land intact, one of them touching down on a golf course.
8:10 a.m.
A 1,760-pound armor-piercing bomb dropped by a high-altitude bomber penetrates the decks of the USS Arizona. The explosion in the forward magazine of the battleship sets off more than a million pounds of gunpowder, and creates a huge fireball. The blast, which sets off shock waves felt throughout the harbor and even by Japanese pilots flying 10,000 feet above, kills 1,177 men aboard. In nine minutes, the Arizona is on the bottom of the harbor and fires aboard it burn for two days.
8:12 a.m.
The USS Utah, a former battleship converted into a target ship, capsizes after taking two torpedo hits. Fifty-eight men are lost.
8:17 a.m.
Through the flames and smoke, the destroyer USS Helm speeds to the open sea. As the Helm leaves the channel, a lookout spots a Japanese sub snagged on a reef. The Helm "turned hard right toward enemy submarine," shoots and misses. The two-person sub breaks free and submerges. But it snags again. Trying to escape the foundering sub, one crewman drowns. The next day, the other is washed ashore near Bellows and becomes the United States' first World War II prisoner of war.
8:39 a.m.
As the destroyer USS Monaghan tries to get out of the harbor, a nearby U.S. ship signals that it has sighted a submarine. The Monaghan heads for the sub at top speed, hits it with gunfire, then rams it and drops depth charges. The charges are so close that when they explode, the blasts lift the Monaghan out of the water but do not damage her. The sinking midget submarine manages to fire a torpedo. But it does not hit anything.
8:50 a.m.
The USS Nevada gets underway and, with anti-aircraft guns blazing, heads for the open sea. Japanese planes of the second wave bomb her, hoping to sink her in the narrow harbor entrance and close off the harbor. Its captain deliberately grounds the ship off Hospital Point to avoid that situation.
8:54 a.m.
The second wave of Japanese planes meets heavy antiaircraft fire. Bombers attack the Navy Yard dry docks and hit the battleship USS Pennsylvania. Another bomber hits the destroyers USS Cassin and USS Downes. Onboard ammunition explodes, and the Cassin rolls off its blocks and into the Downes. Bombs hit the light cruiser USS Raleigh. Crewmen jettison gear to prevent capsizing.
9:30 a.m.
A bomb blows off the bow of the destroyer USS Shaw, creating a massive explosion that cuts the ship in two; pieces of the ship rain down half a mile away.
10 a.m.
The second wave of Japanese fighters heads back to the carriers. Of the 29 Japanese planes lost, anti-aircraft guns probably shot down 15. Exuberant Japanese pilots urge a third strike on Pearl Harbor, particularly gasoline tanks which supply fuel to ships and planes.
Aftermath
Japanese commanders, saying the attack has been successful, rule out a third strike. One reason is a possible retaliation by U.S. aircraft carriers that were not in the harbor. By 1 p.m., the strike force is on its way home.