I actually think Okinawa is a very fitting name for the system, it being a tiny island and former independant kingdom quite a swim from mainland Japan.
You could compare it with Orkney (Bretonia not being allowed to physically claim it, with it now being regarded as a borderworld).
Orkney is also an island a bit off the mainland (houses ALL of Britains Nuclear submarines, and all of the nuclear deterant of the UK, minor point).