One month after the Battle of the Coral Sea, Admiral Isoroku Yamamoto, the commander of the Combined Fleet, determined that the US carrier fleet needed to be destroyed. The US Navy was numerically inferior, so Yamamoto needed to lure them out into a trap.
The Japanese had been planning to seize Midway Island to use as a base for future attacks against the US in Hawaii and the Pacific. Yamamoto decided to go ahead with the invasion, and destroy American reinforcements with a massive force.
What Yamamoto did not know, was that US intelligence had cracked the Japanese codes, and were fully aware of Japan's plans. They sent their own force of three aircraft carriers and prepared Midway's air component for battle.
The following battle was a massive loss for the Japanese. All four of Japan's heaviest aircraft carriers, Akagi, Kaga, Soryu, and Hiryu were sunk. The Japanese also lost one cruiser, 292 aircraft, and over 2,500 sailors and airmen.
The US lost the aircraft carrier USS Yorktown — which was repaired after it was damaged in the Coral Sea — a destroyer, and 145 aircraft. 307 US sailors and airmen were killed.
Crucially, the Japanese aircraft carriers that were lost or damaged in the Battle of the Coral Sea were not able to participate in the battle, an element that helped secure an American victory.
The battle proved to be a turning point. Japan had lost its largest aircraft carriers and best naval aviators, and the Allies went on the offensive in the Pacific, with the Battle of Guadalcanal starting two months later.