Why did the US want to capture the island of okinawa?

United States forces were scheduled to invade the mainland of Japan at its southernmost island -- Kyushu. (The invasion took place April 1, 1945)The invasion and control of Okinawa was important so the U.S. could build Hugh airfields there and then our B-29 Superfortress bombers to soften up the island prior to the invasion. After the invasion smaller craft could operate from the same airfields to provide troop movement and support. Okinawa was also close enough to be a foreward "jumping off" base to assemble troops, ships, supplies, arms, etc. for use prior to, during, and following the invasion. Once Kyushu was taken U.S. forces could then move up the mainland of Japan to Tokyo -- and victory.We had taken Iwo Jima in February of 1945 so we would have airfields from which our bombers could bomb Tokyo but Iwo was too far away from Kyushu to act as a foreward base. Iwo was 800 miles from Kyushu -- Okinawa was only 350. Hope this helps...... vcsWW2