Okinawa Invasion: Rockets from an American LCI (landing craft, infantry) stream toward Okinawa, in the Japanese Ryukyus, just before U.S. 10th Army forces invaded the strategic island on March 31, 1945. By April 8, U.S. forces controlled a third of the island, and by the end of May the island was taken and superforts were using Okinawa airstrips to bomb Japan. August 20, 1945.