You are South in 3NT. How are you going to make the contract after East plays the jack of hearts at trick one and you win the queen?
*From I Challenge You by Victor Mollo
Count your sure winners: one spade, two hearts, one diamond, and one club. You need to develop five more winners to get to nine tricks. The diamond suit should set up for four or five of the additional tricks. That gets you to eight or nine tricks. By driving out the king of spades you will have at least nine tricks.
But there is a danger that the opponents will get five tricks before you can get nine! How are you going to avoid that danger and what card do you play at trick two?
This is a common dilemma for declarer, so it would benefit you to work it out before scrolling down for the solution:
It looks like West started with five hearts and East with three. The danger is that West may cash three heart tricks if she has an entry with the king of spades. And East is certain to continue the heart attack when she gets in with the king of diamonds. To prevent this, you must keep East off lead while West still has an entry with the king of spades. Play the queen of spades at trick two. No matter who wins that trick, you have a sure nine tricks when East gets in with the king of diamonds: two spades, two hearts, four diamonds, and one club. And you will make an overtrick if West has the king of diamonds. If East happens to get in with the king of spades at trick two, you can safely duck her heart return and take your ace when she continues hearts at trick four.