The challenge is to make Ryukyu an independent and sovereign state surviving to the present day.
Have them get fed up with the American bases and separate to get rid of them.
not enoug Man power and do you think America will stand it while China is Agressive?
Find some way for the British to turn the Ryukyu Kingdom into a protected state where they take over control of foreign policy and defence but internal matters are left to the native monarchs as like what happened with Brunei or Tonga. During WWII the Japanese invade the kingdom just as they did with other British territory and occupy it until the islands are liberated towards the end of the war. Post-war since they've never been a part of Japan and won't have suffered the suppression of Ryukyuan culture, language and religious practices the Japanese carried out after annexing them in 1879 in our timeline there would be no reason for them to join with Japan. From there you can take things where you want. If it happened after the Satsuma domain annexed the Amami islands in the early 1600s I believe it was you could potentially see Japan being forced to hand them back, personally however I think they would be more trouble than they were worth since by then the local population is likely to have been pretty, forcibly, culturally assimilated. But it's not like international relations have always run on total logic.![]()
Will their native monarchy still be in power?
Not that challenging really. Have the Ryukyus remain in American hands after WWII, and they can end up as a protect... associated state like the Marshall Islands or Palau. With China and Japan as neighbors, they're going to need a powerful friend.