Overview: Across Okinawa's islands, you will find the stone walls of castle ruins. The Ryukyu Kingdom was a country for 350 years before it was absorbed into Japan. From the 12th to 15th centuries, it erected many gusuku or castles to protect the land and also to provide a place of worship. Alfie Goodrich sets out to discover the beauty and mystery of Okinawa's old kingdom through its gusuku.