After a period of conflict between the Sanzan principalities, control of the Ryukyu Kingdom was concentrated at Shurijo Castle in 1429. At the time, the castle was smaller than it is today as it was limited to the so-called naikaku (the inner compound). When the outer compound was added in the first half of the sixteenth century, the scale of the castle was extended to cover an area of approximately four hectares measuring 400 meters east to west and 200 meters north to south. The appearance of the castle gates tell the story of these transitions. The Zuisenmon, the Shukujunmon, the Bifukumon, and other gates in the inner compound are topped with wooden structures, so-called yagura, which act as links between the castle walls. The Kankaimon, Kyūkeimon, Keiseimon, and other gates in the outer compound are in the shape of a yagura mounted over arched castle gates. These variations speak of the differences between the periods.
In 2000, “Gusuku Sites and Related Properties of the Kingdom of Ryukyu” was registered under UNESCO World Heritage Site.