Each year on April 28th, the Japanese government commemorates the day Japan saw its restoration of sovereignty in 1952 with a festive celebration. For Okinawa however, this day marks no bright event. The below cartoon summarizes the reasons for this nicely.
Taken and translated from the newspaper Okinawa Times, 28th April, 2013.
NOTE: Seeing as this comic was originally made in Japanese the reading method too follows the Japanese style (different from western style). The place to start reading will be "April 28th 1952?" then "That's right" and without crossing the slightly fatter middle line keep working your way downwards and you'll be alright!