Merrimac Coup

A Merrimac coup occurs when a defender plays an unusually high card to disrupt declarer's communications. Specifically, the high card forces out an entry in declarer's hand or dummy.

The Merrimac coup is named for the U.S. ship Merrimac, which Americans deliberately sank in the Spanish-American War. The ship was sunk in the harbor of Santiago de Cuba to block Spanish ships from entering. (Unlike in bridge, the actual blockade failed.)

		North
		A4
		95
West		8542		East
JT532		AQJT8		K6
876				T3
JT		South		AQ963
964		Q987		K752
		AKQJ42
		K7
		3

East opens 1, but South reaches an ambitious 6 contract. West dutifully leads the J (a spade would be better), won by East's ace.

If East makes a passive return like a diamond, declarer can win, draw trumps, and take a ruffing finesse in clubs against East. Whenever East covers the Q, South will ruff, cross to the A, and use dummy's good clubs to discard spade losers from hand. Making 6.

East has a more interesting alternative at trick 2, which is to lead the K. This Merrimac coup yields an extra spade trick to declarer, but eliminates the vital entry to use dummy's clubs. After South wins dummy's A, no good lines present themselves. If South tries ruffing spades in dummy, East overruffs. And if South sets up clubs via a ruffing finesse, there is no way to reenter dummy to use them.