the Japanese dug an tunnel network under ground on a huge scale to avoid bombings from allied ships, before the invasion of Okinawa.
沖縄県 (okinawa-ken), which is "Okinawa Prefecture", omitting the last Kanji 県 (ken) makes it 沖縄 (okinawa).
Okinawa is an island
Okinawa is a part of Japan so yes, Okinawa was in WWI.
Okinawa is in the northern hemisphere.
Okinawa is in Japan not China.
Okinawa Expressway was created in 1975.
Okinawa Island's population is 1,384,762.
Okinawa no Kaze was created in 2001.
Okinawa Television was created in 1959.
Okinawa Bulletins was created in 1945.
Okinawa Monorail was created in 2003.
Okinawa Rail was created in 1981.