those in the japan camp are waaaaaaaaaaaaaaaay too focused on the technicalities you'd be hard pressed to find any book that introduces joseon was a tributary of china or joseon was a sovereign country nation state no it'd more like joseon was a country in korea the end so that whole google book page hit is irrelevant and bill price is right the english terms are a sort of a cop out i mean surely you wouldn't call the british empire a tributary of china prior to the opium wars despite this denomination joseon was and acted as a independent sovereign nation this excerpt explains more about the relationship and how such terms may be confusing