Opening ploy in chess (6)
I believe the answer is:
gambit
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">opening ploy in chess</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 gambit that I've seen before include "Tactic intended to gain an advantage" , "Opening action" , "opening on board" , "Initial move in chess" , "Sacrificial chess opening" .)