Map No. 3 — Okinawa Island Group
The direct advance to the Ryukyus-Bonins line from the Luzon-Marianas was thus conceived within the framework of the general strategy of destroying by blockade and bombardment the Japanese military forces or their will to resist. The Ryukyus were within medium bomber range of Japan, and it was estimated that 780 bombers, together with the necessary number of fighters, could be based there. An advanced fleet anchorage was available in Okinawa. From these airfields and naval bases American air and naval forces could attack the main islands of Japan and, by intensified sea and air blockade, sever them from the Japanese conquests to the south. The captured bases could also be used to support further operations in the regions bordering on the East China Sea. Finally, the conquest of the Ryukyus would provide adequate supporting positions for the invasion of Kyushu and, subsequently, Honshu, the industrial heart of Japan.{13}
The Ryukyu Islands lie southwest of Japan proper, northeast of Formosa and the Philippines, and west of the Bonins. (See Map No. l.) The islands, peaks of submerged mountains, stretch in an arc about 790 miles long between Kyushu and Formosa and form a boundary between the East China Sea and the Pacific Ocean. The archipelago consists of about 200 islands, only 30 of which are large enough to support substantial populations. The climate is subtropical, the temperature ranging from about 60F. to 83F. Rainfall is heavy, and the high humidity makes the summer heat oppressive. The prevailing winds are monsoonal in character, and between May and November each year the islands are visited by destructive typhoons.{14}
Approximately in the center of the arc is the Okinawa Group (Gunto) of some fifty islands clustered around the island of Okinawa. The Kerama Islands lie in an area from ten to twenty miles west of southern Okinawa. Kume, Tonachi, Aguni, and Tori form a rectangle to the north of the Kerama Group. Ie Shima stands off the jutting tip of the Motobu Peninsula on northern Okinawa, while farther to the north lie the Iheya Islands and Yoron. A chain of small islands, called by the Americans the Eastern Islands, extends along the eastern shore of southern Okinawa. Lying in the path of the Japan Current, the entire Okinawa Group is surrounded by seas warm enough to allow the growth of coral, and hence all the islands are surrounded by fairly extensive reefs, some of which extend several miles off shore. (See Map No. 2.)
Okinawa is the largest of the islands in the Ryukyus. Running generally north and south, it is 60 miles long and from 2 to 18 miles wide, with an area of 485 square miles. It is entirely fringed with reefs: on the western side the reef lies fairly close to shore and is seldom over a mile wide; on the eastern side, where the coast is more sheltered, the reef extends for some distance off shore, the widest and shallowest points being north of Nakagusuku Bay. (See Maps Nos. II and III.)
OKINAWAN CUSTOMS include the burial tomb and the veneration of ancestors. The burial tombs characteristics of the Okinawan landscape stand out clearly in this aerial view (above) just north of Shuri.