Editor’s note: Contributed by the War in the Pacific National Historical Park. Photos from the Micronesian Area Research Center, National Archives, Naval History and Heritage Command, The Japan Times, War in the Pacific, and Wikimedia Commons collections.

26 July 1940

Japanese Envoys. Wikimedia Commons

Relations between Japan and the United States deteriorate as America initiates first trade embargo on war-related goods to the Asian nation.
27 July 1940

map asia co-prosperity

Japan declares the Greater East Asia Co-Prosperity Sphere concept desiring to ensure its dominance in Asia and the Pacific and its ability to take raw materials from its neighbors. Japan’s determination to realize the concept through a policy of expansion through aggression would lead to direct conflict with numerous nations, particularly the United States and Britain.


4 December 1941

Naval Governor of Guam, Captain George J. McMillan, receives a Navy Department war warning message and orders to destroy all secret and classified items which was done on the 6th and 7th of December.


7 December 1941

Aircraft of the Japanese navy launch a surprise strike on US military facilities on Oahu, Hawai`i. The attack cripples the navy at Pearl Harbor as the US is thrust into World War II. Killed were more than 2,500 Americans, 21 warships were either destroyed or damaged, 169 aircraft demolished. The attack and others nearly simultaneous across the Pacific, including Guam, and Asia would eventually net Japan an empire of more than 20 million square miles.


8 December 1941

Across the dateline and shortly after the Pearl Harbor attack, Japanese dive-bombers from bases in Saipan, the Marshalls and Formosa, strike Guam, Wake Island, and the Philippines. On this day in the US mainland, President Roosevelt, elected 5 November, describes the attack on Pearl Harbor as “a date which will live in infamy.” US formally declares war on Japan as do Canada and Great Britain.


9 December 1941

Japanese aircraft return to Guam to bomb and strafe Hagåtña, Piti, Sumay and other villages.

10 December 1941

Japanese Invasion of Guam by Kohei Ezaki. Guam Public Library System (GPLS).

In the darkness of early morning, troops of Japan’s South Seas Detachment invade Guam; one group of 400 soldiers lands at Dungca’s Beach in Tamuning, other units, totaling 5,500, come ashore south of Hågat village, at Togcha and at Tumon. After a brief but futile firefight at the Plaza de España between the Guam Insular Guard and the detachment, Capt. George McMillan, naval governor of Guam, surrenders the island to the Japanese about 5:45 am.


11 December 1941

Germany and Italy, partners with Japan since the signing of the Tripartite Pact in September 1940, declare war on the United States. The United States answers in kind.


23 December 1941

On 23 December, after repulsing an initial Japanese landing on 11 December, US sailors, Marines and others surrender Wake Island. Forty-five CHamorus participate in the island’s defense; 10 of those die in the 12 day siege. Initial Japanese force receives support by some ships and aircraft involved in the 7th of December attack on Pearl Harbor. On Christmas Day the Japanese capture Hong Kong.


January – June 1942

Japanese Soldiers. Micronesian Area Research Center (MARC).

The first of three Guam Minseibu (Department of Civil Administration) periods. Commander Hayashi Hiromu’s period (January – June 1942) focused on the recovery of public peace in Guam.


10 January 1942

American military and civilian personnel, Navy nurses, as well as American and Spanish priests on Guam are forced to march to Piti and board the ship Argentina Maru. Their destination: Prisoner of War camps in Japan.


17 March 1942

General Douglas MacArthur, ordered by President Roosevelt to leave the Philippines 11 March evades capture by Japanese forces and arrives in Australia. There, he makes a vow and one of the war’s most famous declarations: “I came through and I shall return.”


30 March 1942

President Roosevelt appoints MacArthur as Supreme Commander Southwest Pacific Area and Admiral Chester W. Nimitz as Commander-in-Chief, Pacific Ocean Area.


9 April 1942

American and Filipino forces on Bataan surrender to the Japanese army under General Homma Masaharu. The “Bataan Death March” begins. About 76,000 American and Filipino survivors are forced to march 60 miles to Prisoner of War camps. As so many are in a weakened and starved state, 5,000 perish; still more die in the camps.


18 April 1942

Launched from the carrier Hornet, 16 B-25 Mitchell bombers, commanded by Lt. Col Jimmy Doolittle, attack military facilities in several Japanese cities. The air strike uplifts America from coast to coast, as the nation is still in shock from Pearl Harbor and the reality of war.


4-8 May 1942

The significance of air power on the sea is highlighted in the first naval battle in history, pitting aircraft carriers against aircraft carriers. Although each side loses a carrier (the Lexington and the Shoho), the US Navy defeats the Japanese navy in the Battle of the Coral Sea. The US notches a strategic victory in the battle in the sea southeast of New Guinea and northeast of Australia. Japan is flustered in its drive to extend battle lines southward toward Australia.


6 May 1942

With the island fortress of Corregidor succumbing to the siege by the Japanese Imperial army, General Jonathan Wainwright, commander of US and Filipino soldiers in the place of MacArthur, surrenders. The Philippines falls.


3-6 June 1942

US Navy carriers under Admiral Nimitz confront carriers of a fleet commanded by Japan’s Admiral Isoroku Yamamoto in the Battle of Midway. After an initial Japanese air strike on Midway Island, US Navy pilots seize the advantage when they catch Japanese aircraft on carrier decks fueling and rearming. At battle’s end, sunk are the Japanese carriers Kaga, Soryu, Hiryu and the Akagi. Although the Yorktown sinks following the battle, the US victory would prove to be a critical turning point of the war in the Pacific.


7 June 1942

Japanese invade the American possessions of Attu and Kiska in the western region of the Aleutian Islands in Alaska. The two islands, Wake and Guam, are the only American territories occupied by the Japanese in World War II. Indigenous Aleut native Americans are evacuated by US from the island chain and transferred to vacant canneries and other facilities in the Alaskan panhandle; the transfer devastates Aleut traditional culture.


22 June 1942

Trying to push southward to extend its battle lines closer to Australia, Japan begins its Papua campaign with the objective of capturing Port Moresby. Soldiers attempt overland route through extremely dense jungle and rough terrain.

June 1942 – October 1943

Japanese Occupation. War in the Pacific Collection.

The second of three Guam Minseibu (Department of Civil Administration) periods. Commander in the reserve Homura Teiichi period (June 1942 – October 1943): the most stable, but active Minseibu period.


7 August 1942

In first US amphibious operation of war, the 1st Marine Division lands at Guadalcanal, the largest island of the Solomons. Unveiled is the tactical blueprint for taking the war through the Pacific to Japan; a landing force attacks as aircraft and naval gunfire, in close support, strike at enemy ground forces. The Japanese, after months of bitter fighting, withdraw from Guadalcanal in February 1943.


12 September 1942

Navy sailors Chief Machinist Mate LL Krump, Chief Aerographer LW Jones, and Yeoman First Class A. Yablonsky were discovered in the Manenggon area in September 1942 and were beheaded by the Japanese. They were three of the six Navy sailors on island prior to invasion.

October 1942

The Japanese Administration implemented an educational program using their language. Children between the ages of 7 to 16 were assembled in the respective schools in the outlying districts and in Hagåtña. They also started a boarding school for adult men and women and some young people. Three civilian Japanese instructors were brought from Japan for this special school.


12-13 November 1942

Naval forces collide in the sea battle of Guadalcanal. The Japanese battleships Hiei and Kirishima are sunk. The sinking follow those of the Japanese carrier Ryujo on August 24, and the American carriers Wasp, on September 15 and the Hornet on October 27. Though losing ships, the US accomplishes a strategic victory as the battle demonstrates the Japanese inability to resupply or reinforce troops at Guadalcanal.


November 1942

Navy sailors radiomen first class Al Tyson and machinist mate first class CB Johnston were found and shot in Machananao after having been harbored by Frank D. Perez and others. They were two of the six sailors on island prior to the invasion.

22 January 1943

At Buna and Gona in New Guinea, US and Australian troops catch Japanese forces in retreat from a failed campaign to take Port Moresby. The Allied counter attack ends the Japanese threat to Australia; the victory is the first decisive triumph on land for the Allies in the Pacific.

February 1943

Sgt. Shoichi Yokoi, 28 years old, is transferred to the 38th Regiment in Guam. He is assigned to the supply corps of the Japanese naval garrison.


30 May 1943

US forces land and retake Attu, in the far western Aleutian islands, from the Japanese, who occupied the island and nearby Kiska since 7 June 1942. (Kiska was taken 15 August 1943 without a battle because Japanese had evacuated secretly under the cover of fog more than two weeks earlier.)


30 June 1943

With the Navy securing control of the Bismarck Sea in March, MacArthur, landing in New Guinea, and Admiral William “Bull” Halsey, his forces coming ashore in the eastern Solomons, put into motion Operation Cartwheel. The operation, which establishes airfields from which to bomb the major Japanese base of Rabaul, takes months to accomplish but dooms the base.


27 August 1943

Japanese transport vessel Tokai Maru is sunk on 27 August 1943 by the submarine Snapper in Apra Harbor.


November 1943 – March 1944

Japanese Guards. War in the Pacific Collection.

The final of three Guam Minseibu (Department of Civil Administration) periods. Commander in the reserve Homura Teiichi period (November 1943 – March 1944): preparation for fortification and militarization of the island.


1 November 1943

Still trying to isolate Rabaul, US forces under Halsey invade Bougainville; among the units involved is the 3rd Marine Division, destined to invade Guam. Securing Bougainville takes until April 1944 but the operation sustains US superiority in the region.


20 November 1943

Nimitiz begins “island-hopping” in the central Pacific through Micronesia. The 2nd Marine Division invades heavily fortified Tarawa, and the Army’s 27th Infantry Division lands on Main (both part of Kiribati, formerly the Gilbert Islands). The battles in this eastern-most part of the Micronesian Region are costly; while only 60 men were killed at tiny Makin, 1,056 die in 76 hours of fierce fighting at Tarawa. Future invasions, in the Marshalls and Marianas, feature better intelligence, better ship-to-shore transfer of troops, equipment and supplies.


26 December 1943

Forces under MacArthur achieve landings at New Britain in the Bismarck Archipelago. From there, MacArthur begins to secure the western Solomons, New Guinea, and eventually the Philippines. With the operations of MacArthur and Halsey complementing each other in the southwest Pacific, the Allies mount another offensive to nearly parallel Nimitz’s path through the central Pacific toward Japan.


1 February 1944

The drive by US forces through Micronesia and the central Pacific continues. In the Marshall Islands, the 4th Marine Division and the Army’s 7th Infantry Division attack Japanese forces on Kwajalein and on Roi Namur. Also invaded and captured is Majuro, the atoll which is the present day capital of the Republic of the Marshall Islands. The costly lessons of Tarawa pay off; only 334 men are killed in the landings.


7 February – 7 March 1944

US campaign seizes the Admiralty Islands, north of Papua New Guinea. US forces now greatly hinder Japanese supply lines from Rabaul in the south Pacific to Truk (now Chuuk, Federated States of Micronesia), Japan’s major naval base in the central Pacific. The path is clear for the capture of the Marianas.


17-18 February 1944

Borne by carriers of the fleet of Admiral Marc Mitscher, Navy aircraft conduct a series of raids on Truk (now Chuuk, Federated States of Micronesia), a major Japanese naval installation in the western Pacific. One raid was the first nighttime bombing mission by the Navy. Japanese losses from the raids are heavy; 275 aircraft, 10 ships and 31 merchant ships. Ship tonnage lost – 200,000 tons – was the highest in the war for a single action.


19 February 1944

US forces under Nimitz continue westward through Micronesia toward Japan. Another atoll is taken when Eniwetok is invaded and taken by the 2nd Marine Division. More than 250 men are killed, light when compared to Tarawa.


23 February 1944

US carriers carry on their program of destruction, this time their pilots unleashing their firepower in raids on the Marianas. US Navy pilots down 168 aircraft and sink two freighters while losing only six aircraft.


15 June 1944

The 2nd and 4th Marine Divisions land on Saipan in the Marianas, beginning the first battle fought in Japan’s inner defense line. US forces find fighting extremely difficult against a Japanese enemy growing desperate. Americans complete capture of Saipan on July 9.


19-20 June 1944

West of the Mariana Islands, the naval Battle of the Philippine Sea is joined when the US fleet of Admiral Mitscher intercepts the Japanese fleet of Vice Admiral Jisaburo Ozawa. Ozawa’s force is rushing to catch the American invasion force on the beaches of Saipan. In what would be called “The Great Marianas Turkey Shoot”, US carrier pilots destroy more than 400 enemy plans, sink a carrier and other vessels. Mitscher’s two subs join in the devastating defeat of the Japanese force by sinking two carriers. American losses were more than 100 aircraft and slight damage to the battleship South Dakota.


10 July 1944

Radioman Tweed. War in the Pacific Collection.

One of six Navy sailors, radiomen first class George Tweed, was on island prior to the Japanese invasion. Tweed was rescued by the US Navy Destroyer McCall on 10 July 1944, he was sheltered in an isolated rocky crevice in the northern coastline cliffs on Antonio Artero’s ranch.


10 July 1944


Manenggon survivors. Photo courtesy of Don Farrell.

Manenggon Concentration Camp: General Takashina, the Japanese commander, ordered all CHamorus throughout the island to be evacuated from their villages and marched to campsites in the southern interior of the island. Thousands of people, from infants to the elderly, were forced to march to the Manenggon camp, with very little possessions, from as far north as Yigo and as far west as Hågat.


12 July 1944

Father Jesus B. Duenas. Micronesian Area Research Center (MARC).

Father Jesus B. Duenas is beheaded for his refusal to disclose the whereabouts of radioman George Tweed. On 8 July 1944, Father Duenas and his nephew, former Island Attorney Eduardo Duenas, are arrested by Japanese authorities in Inarajan. They are were tortured and beheaded on 12 July in Ta’i,  along with Vicente Baza and Juan (Mali) Pangelinan.


15 July 1944

0009-M7 005-Memorial Services

Merizo Memorial Service. Micronesian Area Research Center (MARC)

Tinta Massacres: On 15 July 1944, the 800 or so Merizo residents were rounded up and taken by soldiers to the Geus River Valley. Thirty of the residents were lead into a Tinta cave when Japanese soldiers tossed hand grenades in after them. The Japanese soldiers then took swords and bayonets and began stabbing anyone still alive. Still, by pretending to be dead, 14 of the CHamorus survived.


16 July 1944

Merizo Memorial Services. Don Farrell Collection.

Faha Massacre: On 16 July 1944, male residents of the Faha area in Merizo were rounded up and lead to their death. The exact details are not known, but it is speculated that the Japanese again used machine guns, grenades, and bayonets. None of the Faha victims survived.


20 July 1944

Merizo Men in Canoe. Micronesian Area Research Center (MARC).

The people of Malesso’ learned about the Tinta and Faha Massacres and were outraged. On 20 July, in broad daylight, a group of Merizo men stormed the Japanese quarters at Atate (another area of the village) and killed 10 Japanese soldiers. Only one Japanese soldier escaped, fleeing towards the neighboring village of Inarajan.


20 July 1944

In Hagåtña, on the night of 20 July, 11 CHamoru men, women, and children were accused of signaling US aircraft and bayoneted to death by Japanese soldiers. Two teenagers escaped by faking death after being stabbed by bayonets.


21 July 1944

Marines Pinned Down, Chonito Ridge. War in the Pacific Collection USMC-87283.

More than two and half years after Pearl Harbor, the US returns to Guam to liberate the island from Japan. Confronted by intense fire from Japanese defenders, the 3rd Marine Division lands at Asan, and to the south, the 1st Provisional Marine Brigade, followed by the Army’s 77th Infantry Division, goes ashore on the beaches in Hågat.


23 July 1944

The Fena Caves Massacre. American troops invaded the island and Japanese soldiers killed more than thirty young men and women from Agat and Sumay with grenades and bayonets in the caves near Fena Lake, raping many of the women before killing them. In some accounts, it is reported that sixty-six others barely survived the massacre.


24 July 1944

Three days after US forces land on Guam, and using Saipan as a staging area, the 4th Marine Division invades Tinian. Feigning a landing on the beaches near the island’s town, the Marines instead establish a beachhead at an undefended spot in the island’s northwest, a spot thought to be too small by the Japanese defenders for an invasion force. The landing’s success led to the island being declared secure eight days later.


25-26 July 1944

Unsuccessful in keeping US forces from establishing a beachhead, Japanese forces in Guam counter-attack during the night at Asan-Piti, but fail. Killed in a series of banzai charges are 3,500 Japanese soldiers.


28 July 1944

In Guam, two American invasion forces link up at Mount Tenjo. With the final beach line secured, US troops advance to the north, chasing retreating enemy soldiers.


8 August 1944

Charging North. Don Farrell Collection.

CHagui’an Massacre: On 8 August US forces charging northward found a Japanese truck loaded with 24 decapitated bodies of CHamoru men. They continued to search the area until the following morning, when 21 more bodies were found.


9 August 1944

The Battle of Aitape in Palau New Guinea ends after a month of fighting. Unable to capitalize on a breakthrough of Allied lines, Japanese troops under General Adachi Hatazo falter, then are fatally enveloped in a counterattack. More than 10,000 Japanese soldiers perish in the last battle of Papua New Guinea.


10 August 1944

General Roy Geiger declares Guam secure by American forces. Military officials are now tasked with two duties: providing car to war-ravaged island residents and molding Guam as a staging area for naval and air operations against Japan.


15 September 1944

US forces hit another Japanese stronghold, this time Palau. There the 1st Marine Division invades Peleliu and the 81st Infantry Division strikes at Angaur. But the battle of Peleliu continues for weeks and is reminiscent of Tarawa’s heavy fortifications but with a twist – Peleliu possesses caves. At battle’s end, the dead: nearly 1,300 Marines and almost 300 soldiers from units called in to relieve the worn and ragged men of the Corps.


20 October 1944

MacArthur makes good on his vow to return to the Philippines as four US Army division land at Leyte. By February US forces have landed in Luzon and go on to occupy Manila.


24-25 October 1944

The Battle of Leyte Gulf, comprised of four separate engagements and the largest of the war, results in devastating defeat of the Japanese navy. Four Japanese carriers are sunk as the US solidifies its ability to retake the Philippines. For the first time “kamikazes” – pilots on suicide missions – are send into battle in a desperate attempt to halt the US advance toward Japan.


19 February – 16 March 1945

The siege of Iwo Jima nearly takes a month to complete. The volcanic isle leaves behind a legacy written in blood by the 3rd, 4th, and 5th Marine Divisions; US casualties are 6,800 dead, 20,000 wounded. There are practically no survivors of the 21,000 Japanese defenders.


1 April – 22 June 1945

USS Intrepid (CV-11) afire, after she was hit by a Kamikaze off Okinawa. 80-G-328441

With American forces nearing the Japanese home islands, the Japanese up the ante at Okinawa. Kamikazes spearhead the defense of the homeland, and nearly 2,000 soar to attack the US fleet supporting the invasion force. It is bloody at battle’s end; 12,500 American troops and 110,000 Japanese dead.


6 August 1945

Three months after Germany has capitulated to the Allies, US officials desire to end the war quickly and without a bloody invasion of the Japanese homeland. It is decided to utilize a secret and terrible weapon. The “Enola Gay”, a B-29 bomber of the 509th Composite Group based in Tinian, drops the first atomic bomb in history on Hiroshima.


9 August 1945

The decision is made to unleash another atomic bomb, this time on Nagasaki. Bock’s car, another B-29 bomber of the 509th Composite Group on Tinian, drops the weapon. In the two atomic bomb detonations, more than 100,000 people perish; still more will die from injuries and radiation.


15 August 1945

In a radio broadcast which was the first public speech by a Japanese emperor, Emperor Hirohito announces the surrender of Japan.


2 September 1945

The Japanese formally surrender to the Allied powers in a ceremony aboard the US battleship Missouri in Tokyo Bay.


24 January 1972

Sgt. Shoichi Yokoi, the last Japanese straggler, is captured by Manuel De Gracia and Jesus Duenas. The two CHamoru men were checking their fish traps when they found Yokoi and subdued the 57 year old Sergeant after he charged at them.