April 1

Battle of Okinawa Begins — Operation Iceberg

60,000 U.S. troops landed on Okinawa's beaches against surprisingly light initial resistance — the Japanese had withdrawn inland to fortified positions. The 82-day battle that followed became the largest amphibious assault in the Pacific War.

Okinawa's massive casualties on both sides — and the mass suicide of 150,000 Okinawan civilians — convinced American planners that invading Japan's home islands would cost over a million lives, directly influencing the decision to use atomic bombs.