The Battle of Okinawa was a great battle of World War II. It took place on Okinawa Island in the Ryukyu Islands (south of the four big islands of Japan). The battle was between the military forces of the Empire of Japan and the Allies. It was the second biggest amphibious battle (from sea to land) of World War II, after the Battle of Normandy. It was also one of the longest battles in history, from April to June 1945. The Allies won the battle and occupied Okinawa. Today, Okinawa is Japanese territory, but there are still American military bases there.