A similar motive is met in coup en passant, where indirect finesse is used instead of direct.
In an earlier text by George S. Coffin,[2] he names the trump coup as an "Overruff Finesse Endplay".
The king of spades is onside, but declarer (South) cannot finesse against it because dummy has no trumps remaining.
A similar tactic can also be used to create an endplay situation, with similar results to the more ordinary trump coup: NW ESIn this six-card ending, originally given as a whist hand, clubs are trumps and the lead is in the North hand.
If he executes the coup but then fails to cash both spades before touching trumps, East will lead his remaining spade to force South back on lead to give up a second trump trick.
Often, for a trump coup to work, the key defender must have a suitable distribution in other suits, so that he cannot ruff a declarer's winner prematurely.