Why was operation downfall carried out?

Operation Downfall was the planned Allied invasion of Japan during World War II, intended to bring about the country's unconditional surrender. It was conceived in response to the fierce resistance encountered in battles like Iwo Jima and Okinawa, which suggested that a conventional invasion would incur massive Allied casualties. The operation was ultimately rendered unnecessary by Japan's surrender following the atomic bombings of Hiroshima and Nagasaki in August 1945.