Gusuku are usually located in high places or hills overlooking a city.
They are built with elongated sturdy stonewalls.
Gusuku normally has a sacred area. People visit these sacred areas as a place for worship til today. It makes most gusuku a part of Okinawa’s historical sites.
The most prominent one, because it was reconstructed after World War II, is the palace of Shuri.
Gusuku are, in simple term, castles or fortress during the Ryukyu period. Most of their walls or main foundations are that remain. During the Ryukyu period, these fortress are as simple as the stonewalls, solely to protect kingdom people to do work and trades using the high grounds for outlook and the sacred areas to pray to guardian spirits.
My most favorite Okinawa castle ruin is Katsuren.
Wikipedia listed 20 castle ruins in Okinawa. I’ve been to five of it. I’m that awesome. :D It’s hard for a commuter to go places, yah know. The first one I visited is Zamiki Castle.
We saw a couple on their kimono.
The area we went to in Cape Kyan is actually a gusuku.
Urasoe is also currently under reconstruction.
Obvious recommended places to go to in Okinawa are Churaumi Aquarium, Shuri Castle and Okinawa World. Obvious must do and see are snorkelling, any festival, and cherry blossom. If you happened to have an ample time in Okinawa, consider visiting a gusuku or two. Reimagine Okinawa as it used to be and go see Okinawa in good views.