Region on the South China Sea (5)
I believe the answer is:
macao
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">region on the south china sea</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for macao that I've seen before include "Eastern city" , "Former Portuguese colony in China" , "Portuguese province" .)