Largest of the Ryukyu Islands (7)
I believe the answer is:
okinawa
'largest of the ryukyu islands' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for okinawa that I've seen before include "Japanese location" , "American victory, June 1945" , "Region of southern Japan, scene of fierce fighting in 1945" , "battle!" , "Japanese island captured by US in June nineteen forty five" .)