Battle of Midway
1. On May 2 messages that were intercepted by the U.S. from Japan began to indicate some forthcoming operation, and a key fact, the planned day-of-battle position of the Japanese carriers, would be divulged in a notice sent on May 16. By the time Nimitz had to make final decisions, the Japanese plans and order of battle had been reconstructed in considerable detail.
2. Torpedo bombers became separated from the American dive-bombers and were slaughtered (36 of 42 shot down), but they diverted Japanese defenses just in time for the dive-bombers to arrive; some of them had become lost, and now by luck they found the Japanese.
3. United States was able to preempt and counter Japan’s planned ambush of its few remaining aircraft carriers, inflicting permanent damage on the Japanese Navy.
Allies: the victory allowed the United States and its allies to move into an offensive position. Also weakened the Japanese fleet to where they were heavily outnumbered. The island was important because it was able to hold a landing stretch for planes.
Axis: Japan was unable to secure the island and lost communication advantages making them weak toward the U.S. powers.