It's more complicated than that: Ryukyu was a tributary of both Japan and China, and de facto a vassal state of Satsuma from 1609 onwards. https://en.wikipedia

It's more complicated than that: Ryukyu was a tributary of both Japan and China, and de facto a vassal state of Satsuma from 1609 onwards. https://en.wikipedia.org/wiki/History_of_the_Ryukyu_Islands#Ryukyu_Kingdom https://en.wikipedia.org/wiki/History_of_the_Ryukyu_Islands#...