Post-World War II Okinawa was ruled by the United States Civil Administration of the Ryukyu Islands and was RHT. It was returned to Japan in 1972 but did not convert back to LHT until 1978. The conversion operation was known as 730 ("Nana-San-Maru", which refers to the date of the changeover, 30 July). Okinawa is one of few places to have changed from RHT to LHT in the late 20th century.