Problem

The Auction:

You are South on this deal, declaring 2♥ after West opened a 15-17 1NT. West leads the ♦5, you choose to win the trick with dummy's ace. At trick two, you exit with a spade off of dummy, East wins the trick with the queen. East plays a trump, West wins the ace and plays back another trump. Plan the play.

Solution

Your side has a combined holding of 18 points, the opponents therefore have 22 points. West has advertised 15-17, so East has 5-7. East's spade play typically promises the king and queen, so he can have at most another queen. When West returns a heart after winning the ♥A, it is tempting to finesse the ten. However, if East has the ♥Q, he will back a third trump to lock you in dummy. If you win and exit a spade, the defenders will cash two more rounds of the suit, and stick you in dummy with a diamond, after which you will have to lose a club trick.

You cannot do any better by winning the king on the heart return - the same problem exists. If you exit a spade after going up with the ♥K, the defenders will cash their spade tricks, the ♥Q, and lock in in dummy with a diamond. The solution is to unblock the ♥K under the ace! This has the effect of creating a trump entry to hand, in order to take a club finesse. Later, if the defenders do not play diamonds, you can ruff a club back to hand and take the diamond finesse.

The only other noteworthy variation is when declarer sticks in the ♦J from dummy. If declarer exits with a spade at trick two, and East wins the ♠Q and backs a trump to West's ace, unblocking the ♥K would once again result in success. In this scenario, declarer can survive even without unblocking the ♥K. He should win the heart return with the king though, cash his diamond honors, and exit with a spade; the defenders will then be forced to provide an entry to the South hand.

Par Contract Analysis

The par contract on this deal is 2♠ by East-West. While it appears as if there are six losers in 2♠, North will be endplayed at some stage, and will have to lead away from one of his honors.