[38][39][40] On December 7–8, 1941, Japan attacked the American military base at Pearl Harbor in Hawaii, and invaded the U.S.-held Wake Island, Guam, and the Philippines and the British colonies of Malaya, Singapore, and Hong Kong.

The Japanese achieved great success in the initial six months of the war, allying with Thailand and capturing the aforementioned territories in addition to Burma, Borneo, the Dutch East Indies, New Britain, the Solomon and Gilbert Islands, and parts of New Guinea.

In China, Japan made large gains in Operation Ichi-Go between April and December 1944, while in Burma, the Japanese launched an offensive into India which was reversed by July 1944 and led to its liberation by the Allies in May 1945.

Although Japan had occupied much of northern, central, and coastal China, the Nationalist Government had retreated to the interior and set up a provisional capital at Chongqing, while the Chinese communists remained in control of base areas in Shaanxi.

[57] Conflicts between Chinese Communist and Nationalist forces vying for territorial control behind enemy lines culminated in a major armed clash in January 1941, effectively ending their co-operation.

British, Australian, and Dutch forces, already drained of personnel and matériel by two years of war with Germany, and heavily committed in the Middle East, North Africa, and elsewhere, were unable to provide more than token resistance.

Without inhibitions of any kind, I make it clear that Australia looks to America, free of any pangs as to our traditional links or kinship with the United Kingdom.Australia had been shocked by the speed of the collapse of Commonwealth forces in British Malaya and Singapore, in which around 15,000 Australian soldiers became prisoners of war.

The Pacific War Council was formed in Washington DC on 1 April 1942, with President Franklin D. Roosevelt, his key advisor Harry Hopkins, and representatives from Britain, China, Australia, the Netherlands, New Zealand, and Canada.

[97] The Naval General Staff advocated an advance to the south to seize parts of Australia, but with large numbers of troops engaged in China and Manchuria, the IJA declined to contribute the necessary ground forces for the operation.

Admiral Yamamoto viewed the operation against Midway as the potentially decisive battle of the war, which could lead to the destruction of American strategic power in the Pacific,[105] and subsequently allow for a negotiated peace settlement.

The convoys were challenged by American naval forces with increasing intensity as the campaign wore on, and the IJA troops on Guadalcanal began to suffer from disease and malnutrition as their lines of supply from the IJN were constricted.

[115] The battle had painfully exposed the internal rifts and rivalries that divided the Japanese military regime, and frequently paralyzed its ability to craft coherent strategies and react dynamically to challenges by Allied forces.

On 22 November 1943 US President Franklin D. Roosevelt, British Prime Minister Winston Churchill, and ROC Generalissimo Chiang Kai-shek met in Cairo, Egypt, to discuss a strategy to defeat Japan.

Throughout the war, American, British and Dutch submarines operated out of bases at Cavite in the Philippines (1941–1942),Fremantle and Brisbane in Australia, Pearl Harbor, Trincomalee in Ceylon, Midway, and later on Guam.

In addition, Japan honored its neutrality treaty with the Soviet Union and ignored American freighters shipping military supplies from San Francisco to Vladivostok,[136][137] much to the consternation of its German ally.

[151] By the time campaigning ceased during the monsoon, the Northern Combat Area Command had secured a vital airfield at Myitkyina after a prolonged siege, which eased the problems of air resupply from India to China over "The Hump".

Until the end of the war, the United States Army Air Forces based out of these islands conducted an intense strategic bombing campaign against Japanese cities of military and industrial importance, including Tokyo, Nagoya, Osaka, and Kobe.

The invasion of Peleliu in the Palau Islands on 15 September was notable for a drastic change in Japanese defensive tactics, resulting in the highest casualty rate amongst US forces in an amphibious operation during the Pacific War.

The Japanese navy deployed its largest carrier force of the war for the forthcoming battle: the nine-carrier Mobile Fleet under Vice Admiral Jisaburō Ozawa, supplemented by 500 land-based aircraft.

In all, ten US divisions and five independent regiments fought on Luzon, making it the largest ground campaign of the Pacific War, involving more troops than the US had used in North Africa, Italy, or southern France.

In late 1944 and early 1945, the Allied South East Asia Command launched offensives into Burma, intending to recover most of the country, including the capital of Rangoon, before the onset of the monsoon in May.

[176] The capture of Iwo Jima would provide emergency landing airfields for B-29s and a base for P-51 fighter escorts,[177] as well as land-based air support to protect US naval fleets sailing close to the Japanese Home Islands.

Kuribayashi knew that he could not win the battle, but he nonetheless hoped to inflict casualties so costly that it would slow the American advance on Japan, and perhaps give the Japanese government bargaining power in negotiations to end the war.

Under the command of Admiral Seiichi Itō, the battleship Yamato, the light cruiser Yahagi and eight destroyers sortied from Kyushu as bait, meant to draw away as many American carrier aircraft as possible from Okinawa, in order to leave Allied naval forces vulnerable to large-scale kamikaze attacks.

The attention of the Allies then switched back to the central east coast, with the last major amphibious assault of World War II taking place at Balikpapan on 1 July.

Although the campaign was criticized in Australia as a "waste" of the lives of soldiers, it achieved a number of objectives, such as increasing the isolation of significant Japanese forces occupying the Dutch East Indies, capturing major oil supplies and freeing Allied prisoners of war, who were being held in deteriorating conditions.

This view is explained by Victor Davis Hanson: "because the Japanese on Okinawa... were so fierce in their defense (even when cut off, and without supplies), and because casualties were so appalling, many American strategists looked for an alternative means to subdue mainland Japan, other than a direct invasion.

[209] At the time, Soviet participation was seen as crucial in order to tie down the large number of Japanese forces in Manchuria and Korea, keeping them from being transferred to the Home Islands to defend against an invasion.

The USSR's entry into the war was a significant factor in the Japanese decision to surrender, as it became apparent to the government in Tokyo that the Soviets were no longer willing to act as an intermediary for a negotiated settlement on terms favorable to Japan.

[214] Should we continue to fight, it would not only result in an ultimate collapse and obliteration of the Japanese nation, but also it would lead to the total extinction of human civilization.In Japan, 14 August is considered the end of the Pacific War.