One of Japan’s main goals during World War II was to remove the United States as a Pacific power in order to gain territory in east Asia and the southwest Pacific islands. Japan hoped to defeat the US Pacific Fleet and use Midway as a base to attack Pearl Harbor, securing dominance in the region and then forcing a negotiated peace.
Breaking the Code
The United States was aware that the Japanese were planning an attack in the Pacific (on a location the Japanese code-named “AF”) because Navy cryptanalysts had begun breaking Japanese communication codes in early 1942. The attack location and time were confirmed when the American base at Midway sent out a false message that it was short of fresh water. Japan then sent a message that “AF” was short of fresh water, confirming that the location for the attack was the base at Midway. Station Hypo (where the cryptanalysts were based in Hawaii) was able to also give the date (June 4 or 5) and the order of battle of the Imperial Japanese Navy.
Early on the morning of June 4, aircraft from four Japanese aircraft carriers attacked and severely damaged the US base on Midway. Unbeknownst to the Japanese, the US carrier forces were just to the east of the island and ready for battle. After their initial attacks, the Japanese aircraft headed back to their carriers to rearm and refuel. While the aircraft were returning, the Japanese navy became aware of the presence of US naval forces in the area.
TBD Devastator torpedo-bombers and SBD Dauntless dive-bombers from the USS Enterprise, USS Hornet, and USS Yorktown attacked the Japanese fleet. The Japanese carriers Akagi, Kaga, and Soryu were hit, set ablaze, and abandoned. Hiryu, the only surviving Japanese carrier, responded with two waves of attacks—both times bombing the USS Yorktown, leaving it severely damaged but still afloat. (A Japanese submarine later sank the Yorktown on June 7.) On the afternoon of June 4, a USS Yorktown scout plane located the Hiryu, and the Enterprise sent dive-bombers to attack. That attack left the Hiryu burning and without the ability to launch aircraft before it finally sank.
Over the next two days, the US troops at sea and on Midway continued their attacks, forcing the Japanese to abandon the battle and retreat. The Japanese lost approximately 3,057 men, four carriers, one cruiser, and hundreds of aircraft, while the United States lost approximately 362 men, one carrier, one destroyer, and 144 aircraft. This critical US victory stopped the growth of Japan in the Pacific and put the United States in a position to begin shrinking the Japanese empire through a years-long series of island-hopping invasions and several even larger naval battles.