Largest of the Ryukyu Islands in the North Pacific that was a scene of heavy fighting in World War II (7)
I believe the answer is:
okinawa
(Other definitions for okinawa that I've seen before include "American victory, June 1945" , "Japanese island, capital Naha" , "WW2 campaign" , "coral island" , "Japanese island captured by US in June nineteen forty five" .)