In short
Okinawa was the Ryūkyū Kingdom, independent and tributary to China, until its annexation in 1879. Its culture, language and cooking differ markedly from the rest of Japan.
The gusuku sites — including Shuri Castle, destroyed by fire in 2019 and being rebuilt — are World Heritage. The archipelago stretches a thousand kilometres towards Taiwan.
What it really costs
The flight from Tokyo or Osaka is the main item, and the Japan Rail Pass is useless here: there is no railway, only a monorail in Naha.
A car is essential as soon as you leave Naha, and the archipelago is covered by ferry or inter-island flights. Transport weighs more than housing.
What nobody tells you
Okinawa holds most of the American military bases in Japan on less than one per cent of the national territory. It is a live local political subject, and it shows in the landscape.
Typhoon season runs from July to October and cuts inter-island links for days at a time. April–May and October–November are the windows.
The finest islands are not the main Okinawa but Ishigaki, Miyako and Iriomote, another hour away by air.