The third largest city in Japan (5)
I believe the answer is:
osaka
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">the third largest city in japan</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for osaka that I've seen before include "Japanese port, on Honshu" , "Kinki's capital" , "Japan's third-largest city" , "Port city of southern Honshu" , "Japanese metropolis" .)