Christmas play problem answer

Here is the answer to the first question in my Christmas competition. (The others will be in tomorrow’s column.) How should South play in four spades after West leads a trump, and East follows suit?

South starts with nine top tricks: seven spades and two diamonds. Obviously, if West has the diamond queen, life will be easy. So declarer just knows that that card will be offside.

In addition, if East takes a trick with the diamond queen and gives his partner the lead in hearts, a lowclub shift through dummy’s king could give South a nasty guess. (Since East is a passed hand, he is unlikely to have the diamond queen and club acequeen, because West’s lead marks East with a high heart, probably the king.)

But declarer can avoid those problems. He draws the remaining trump, plays a diamond to the king and exits with a heart, taken by West. What can he do?

If West plays a second heart, South ruffs and leads a diamond. If West shows out (see the diagram), declarer ducks the trick to East, who is endplayed. He must lead a club around to the king, or play a diamond from the queen, or return a heart, conceding a ruffand-sluff. (Declarer ruffs on the board to gain an eighth trump trick.)

If West leads a second diamond, South tries dummy’s jack. If it loses, the suit must be 3-2, and the contract is guaranteed. If East fails to follow suit, the diamond jack is declarer’s 10th trick.

If West leads a club, South plays low from the board and can build up a club trick. He loses at most one heart and two clubs.