The trump coup is a contract bridge coup used when the hand on lead (typically the dummy) has no trumps remaining, while the next hand in rotation has only trumps, including a high one that would have been onside for a direct finesse if a trump could have been led. The play involves forcing that hand to ruff, only to be overruffed. A similar motive is met in coup en passant, where indirect finesse is used instead of direct.
In the end position below, spades are trump. The king of spades is onside, but declarer (South) cannot finesse against it because dummy has no trumps remaining.
Declarer takes all three tricks by playing a heart first. When a club is led from dummy, East has nothing but spades remaining and therefore must ruff, and South can overruff with the ace or queen according to which spade East plays.
A trump coup is not possible in a double-finesse position, since declarer with a holding like A-Q-10 over defender's K-J-x would take the first trump trick and then would have to give the defender a free finesse. In effect, a trump coup against a king (or rather, the second-highest remaining trump) must find it guarded by exactly one other trump. (If East held another card instead of the small trump, say a diamond, North-South could still play the hand as just described, but the trump coup would be unnecessary as South could just drop the king of spades instead.)
Similarly, with A-K-J of trumps in hand, a trump coup against Q-x-x on the right is possible, and so on.
To execute a trump coup, declarer must have exactly the same number of trumps as the defender. If declarer had more trumps, entry could not be given to dummy at the critical point when the defender will have only trumps remaining. Sometimes a declarer with too many trumps, but needing to do a trump coup, can set up the desired position by entering dummy and leading a suit he can ruff, to shorten his own trumps.
Famous quotes containing the word trump:
“If there was one egg in it there were nine,
Torpedo-like, with shell of gritty leather,
All packed in sand to wait the trump together.”
—Robert Frost (18741963)