Stratagem, manoeuvre (6)
I believe the answer is:
gambit
I believe this is a double definition.
'stratagem' is the first definition.
(I know that stratagem can be written as gambit)
'manoeuvre' is the second definition.
(I know that gambit is a type of manoeuvre)
(Other definitions for gambit that I've seen before include "Opening chess move" , "Sacrificial strategy in chess" , "Initial move found in bag, Tim" , "opening on board" , "An opening sacrifice in chess for positional advantage" .)