PEARL HARBOR, Hawaii (AP) — Six months after the devastating attack on Pearl Harbor, Japan sent four aircraft carriers to the tiny Pacific atoll of Midway to draw out and destroy what remained of the U.S. Pacific Fleet.

But this time the U.S. knew about Japan's plans. U.S. cryptologists had cracked Japanese communications codes, giving Fleet Commander Adm. Chester Nimitz notice of where Japan would strike, the day and time of the attack, and what ships the enemy would bring to the fight.

The U.S. was badly outnumbered and its pilots less experienced than Japan's. Even so, it sank four Japanese aircraft carriers the first day of the three-day battle and put Japan on the defensive, greatly diminishing its ability to project air power as it had in the attack on Hawaii....