I got an email from a friend and multiple national champion. “I screwed up this deal in the Vanderbilt. You can use it in your column, as long as I stay anonymous.”
See if you can do better. Sitting South, he held:
♠K J 8 3 ♥8 ♦Q J 10 2 ♣A J 7 3
With both sides vulnerable, he opened 1♦. West overcalled 2NT to show a two-suiter in hearts and clubs. Expert partnerships have agreements here. North cuebid 3♥ to say that he had five or more spades and at least invitational values. (3♠ would have shown a weaker hand.) Right-hand opponent competed to 4♥ and South tried 4♠. LHO went on to 5♥, after which North’s 5♠ bought the contract.
How would you play on the ♣K lead? Aside from the two missing aces, finding the ♠Q is a problem. With West having all the hearts and clubs, it makes sense to finesse against East in spades. Accordingly, declarer won the ♣A and ruffed a club to dummy. (He didn’t want to touch diamonds, risking a ruff there.) He led the ♠10, intending to finesse. A look at the Real Deal will show you what happened:
Good news – the ♠Q was onside. Bad news – East rose with the ♠A and played a heart to West’s ace. West won and played another club. East overruffed the dummy for down one.
What was the error? Crossing in diamonds would have worked, but that was risky. The correct play is a heart at trick two. This cuts the communications. When East later wins his ♠A, he has no way to reach his partner for the overruff. Declarer can reach dummy in diamonds to take the winning spade finesse.