On 7 December 1941, Japan launched a surprise air attack on the US naval base at Pearl Harbor in Hawaii. Japanese forces also overran Allied possessions in south-east Asia and The Philippines. Japan hoped for a short war, seeking to quickly weaken US naval strength and capture strategically vital oil supplies. But American industrial might proved too great to overcome.
In June 1942, a decisive aircraft carrier battle near Midway Island marked the end of Japanese expansion. Allied forces also successfully fought back in New Guinea and the Solomon Islands, and removed the threat to Australia.
USS Yorktown at Midway

The carrier USS Yorktown is hit on her portside during the Japanese bombardment in the Battle of Midway in the Pacific on 4 June 1942. The Yorktown was the only American carrier lost in the battle. Japanese losses included 4 carriers and more than 3,000 men killed or captured.
The United States now had the initiative and began a two-pronged campaign to drive back the Japanese. In the south-west Pacific, General MacArthur advanced towards the Philippines. The main attack was in the central Pacific, where Admiral Nimitz fought an island-hopping campaign with his carrier battle-groups. The capture of islands such as Tarawa, Saipan and Iwo Jima saw heavy casualties on both sides.
Flying over the battleship HMS King George V

Three Grumman Avengers flying over the battleship HMS King George V and other units of the British Pacific Fleet when on the way to attack Sakishima targets in support of the American landing on Okinawa.
In April 1945 the Americans assaulted Okinawa, only 350 miles from Japan. Hundreds of kamikaze suicide planes failed to stop the landings. B-29 bombing raids and a submarine blockade now brought Japan to its knees. The bombing of Hiroshima and Nagasaki was the final act that ended the war.