Why Americans won the Battle of Midway?

The American code breakers at Pearl Harbor were, at almost the last minute, able to decode enough of Japanese radio messages to know that there would be a large-scale attack on Midway. For that reason, the American carriers, support ships, and later, a submarine, were hiding behind Midway when the Japanese struck. The American forces surprised the Japanese, sunk 4 of the aircraft carriers (The Hiryu, Soryu, Kaga, and Akagi) and other ships, with the result that the Japanese turned tail and steamed for home.