In December 1941, Japan set their site on the western and central Pacific Ocean. They wanted to control and dominate the western half of the Pacific. Not only did they attack Pearl Harbor on December 7, 1941, but by the end of the month, Japan had invaded Wake Island, Guam, Siam (Thailand), Hong Kong, Gilbert Islands, Philippines, Burma and Borneo.
On February 15, 1942, Singapore surrenders to Japan.
On February 19, 1942, Japan bombs Darwin, Australia.
By the end of May 1942, Japan had attacked the Solomon Islands, Ceylon (Sri Lanka). The Philippines and Burma surrender to Japan.
On June 7, 1942, the Japanese take control of Attu Island, on the western end of the Aleutian Islands.
By the end of 1942, the Japanese have taken the battle to Midway Islands, Guadalcanal and New Guinea.
In 1943, US Marines and Navy begin pushing back against the Japanese invasions throughout the Pacific with more weapons, troops and determination.
On January 31, 1944, US Marines land on Marshal Islands and begin effort to drive off the Japanese occupation.
On February 18, 1944, US Navy launches massive air raid on the Japanese at Truk Island.
On February 19, 1944, US Marines land on Eniwetok Island to fight the Japanese.
On March 15, 1944, Japan invades India with the desire to also control most of the Indian Ocean.
On March 22, 1944, US lands forces on Hollandia in Dutch New Guinea. At the time, Hollandia, located on the north coast of New Guinea was considered to be part of the Dutch East Indies.
On June 15, 1944, US B-29 bombers flying out of China bomb Japan.
On June 19, 1944, the Japanese carrier fleet is defeated in the Philippine Sea.
On August 22, 1944, Japan pulls back from India.
On October 20, 1944, US forces land at Leyte Philippines.
On October 23-26, 1944, Japan suffers another fleet loss when their battle fleet is destroyed at Leyte Gulf, Philippines.
On December 15, 1944, US forces land at Mindoro, Philippines.
On January 9, 1945, US forces land at Luzon, Philippines.
From February19 to March 16, 1945, the Battle of Iwo Jima, ending with the US conquering the island.
On March 3, 1945, Allied forces take Manilla, Philippines from the Japanese.
On March 10, 1945, US drop firebombs on Tokyo, Japan.
On March 21, 1945, Mandalay, Burma is liberated from Japanese occupation.
From April 1 to June 21, 1945, fierce battle at Okinawa.
On April 7, 1945, US sinks infamous Japanese battleship Yamato.
On April 12, 1945, US President Franklin D. Roosevelt dies from a massive cerebral hemorrhage while sitting for an artist painting his portrait. Vice President Harry S. Truman is sworn in as the 33rd President of the United States.
On June 30, 1945, Luzon, Philippines declared secure, however, small fighting continues with remnant Japanese troops.
On this day, August 6, 1945, an atomic bomb nicknamed ‘Little Boy’ was loaded onto a B-29 bomber named the Enola Gay after the pilot’s mother. At 2:45am, Lt. Col. Paul Tibbets takes off from Tinian Island, in the Marianas and heads for Japan. At 8:16 am, Tibbet is over Hiroshima, Japan when the atomic bomb is dropped and explodes 1,900 feet above the city. The initial blast kills 80,000 Japanese and destroys a large portion of the city. At least 30,000 others were injured at the time of the blast and by the end of 1945, at least 60,000 more Japanese died as a result of the radiation and fallout. The estimated power of the Little Boy atomic bomb was the equivalent to 12,500 TONS of TNT.
President Harry Truman had given the order to drop the atomic bomb on Japan after Japan had flatly refused to unconditionally surrender at the Potsdam Conference. He was determined to end the war as quickly as possible and believed that the use of the atomic bombs would do just that. However, Japan still refused to an unconditional surrender after the dropping of the bomb on Hiroshima.
Sources for the above includes: World War II in the Pacific; The Pacific War; World War Two in the Pacific; Atomic Bomb is Dropped on Hiroshima; The Atomic Bombing of Hiroshima; The Atomic Bombings of Hiroshima and Nagasaki: Chapter 7 – The Attacks