The vital first play is easy to overlook

Mae West said, “It is better to be looked over than overlooked.”

She should have known!

There are a few bridge plays that experts make almost without thinking, but a lesser player would overlook. This deal features one. How should South play in four hearts after West leads the diamond king?

West's two-diamond overcall was natural, obviously. This is a standard expert agreement these days. With at least 5-5 in the two unbid suits, West would have intervened with two no-trump. On the second round, South invited game with three hearts, and North accepted with his suitable-looking hand.

Given that declarer has three spade losers, he needs to play hearts and clubs without loss. That means assuming both finesses are working. But suppose, after winning with dummy's diamond ace, South cashes the heart king. West's discard will be a body blow, and the contract will be unmakable.

Just in case East has all four trumps, South must ruff a diamond at trick two. He continues with a club to the queen, another diamond ruff, a club to the ace and a third diamond ruff. Then he plays a heart to the king to receive the bad news. But he next leads a heart to his 10. South, who has won the first eight tricks, is down to three spades and the heart ace-jack. He exits with a spade and awaits two more tricks with his remaining trumps.

The defenders take their three spade winners, but then East is the victim of a trump coup. At trick 12, South sits with the heart ace-jack over East's queen-eight.