What was the last Allied victory before the bombing of Hiroshima?

4 June 1942: The American aircraft carrier USS Yorktown under Japanese attack during the battle of Midway

Explanation:

4 June 1942: The American aircraft carrier USS Yorktown under Japanese attack during the battle of Midway

For six months after Pearl Harbor, just as Admiral Yamamoto predicted, Japanese forces carried all before them, capturing Hong Kong, Malaya, the Philippines and the Dutch East Indies. In May 1942, in an attempt to consolidate their grip on their new conquests, the Japanese sought to eliminate the United States as a strategic Pacific power.

During the ensuing battle the Japanese suffered the loss of four carriers, one heavy cruiser and 248 aircraft, while American losses totalled one carrier, one destroyer and 98 planes. By their victory at Midway, the turning point of the Pacific war, the Americans were able to seize the strategic initiative from the Japanese, who had suffered irreplaceable losses. Admiral Nimitz described the battle’s success as “Essentially a victory of intelligence”, while President Roosevelt called it “Our most important victory in 1942… there we stopped the Japanese offensive.”