Vienna coup

The Vienna coup is an unblocking technique in contract bridge made in preparation for a squeeze play. It is so named because it was originally published by James Clay (1804-1873) after observing it being executed in the days of whist by "the greatest player in Vienna" - identity unknown.

Examples

♠	A J	Example 1a South to lead
♥	A
♦	-
♣	2
N                  E S		♠	K Q
		♥	K 4
		♦	-
		♣	-
♠	4
♥	Q 2
♦	-
♣	A

On the play of the ♣A by South, East is squeezed but can escape by throwing a small heart. Although the ♥Q is now set up, South must next play either the ♥Q, ♥2 or ♠4 to be won in dummy and has no entry back to cash it; he must now lose a spade to East.

♠	A J	Example 1b South to lead
♥	-
♦	-
♣	2
N                  E S		♠	K Q
		♥	K
		♦	-
		♣	-
♠	4
♥	Q
♦	-
♣	A

However, if instead, South plays the ♥2 to the ♥A, East is squeezed when declarer next leads the ♣2 to the ace.

If East discards the ♥K, declarer cashes the ♥Q discarding the ♠J and leads to the ♠A. If East discards the ♠K or ♠Q, declarer cashes the ♠A and ♠J.

♠	A J	Example 1c South to lead
♥	-
♦	2
♣	-
N                  E S		♠	K Q
		♥	K
		♦	-
		♣	-
♠	4
♥	Q
♦	-
♣	A

In this layout there is no way to get back to the hand by playing the ♣2 to the ace. In this case, the ♥A must have been cashed already at an earlier stage to squeeze East when declarer leads the ♣A and discards the ♦2 from the table.