Strategic bombing of the Japanese mainland began in November, thanks to victories that summer and fall in the Mariana Islands. Under the leadership of Admiral Nimitz, the U.S. launched amphibious assaults on Saipan, Guam and Tinian in June and July. Japanese troops contested every inch of ground but ultimately succumbed to overwhelming U.S. military superiority.
In a massive air battle at Saipan, the Japanese lost more than 400 planes to an American loss of less than 30. Stripped of carrier planes, the Japanese fleet fled westward, but American planes in pursuit sank several vessels, including three carriers. Only three American ships were damaged in this engagement, known as the Battle of the Philippine Sea.
Capture of the Marianas brought Japan within reach of the Army Air Forces’ huge new bomber, the B-29, which was able to make a nonstop flight of the 1,400 miles to Tokyo and back. Construction of airfields to accommodate B-29’s began in the Marianas before the shooting had stopped, and in late November 1944 bombing of the Japanese mainland began.
Tiny Tinian, a Marianas island of about 40 square miles, was transformed into the busiest airfield of the war, with six 8,000-foot runways. Later it would serve as the launching point of the planes that dropped atomic bombs on Hiroshima and Nagasaki.