An important part of declarer’s job is to play close attention to how the opponents defend on each deal. It is good policy to assume that they are defending in their own best interests, so whatever they do should be given careful consideration.

Take this case from the 2003 North American Open Pairs, where declarer failed to draw the proper inference from the opponent’s defense. South reached four hearts, and West led the spade deuce.

East took the top two spades and continued with a third spade, ruffed by South with the three as West followed with the queen. East’s unusual defense — helping declarer establish dummy’s 10 as a trick — failed to make an impression on declarer, who next led the queen of hearts and finessed.

This was the opening East had hoped for. He took the king and returned his fourth spade, and South was doomed. If he ruffed low, West would overruff with the ten, and if he ruffed with the jack, East’s nine would become a trick.

Declarer could have averted this ignominious outcome simply by crossing to the jack of diamonds and leading a heart toward his Q-J-7. As long as the opposing hearts were divided 3-2, this would have assured the contract.

If East rose with the king and returned a spade, South could ruff with the jack, after which his queen and dummy’s ace would take care of the missing trumps. And if East did not rise with the king, declarer would win and play the ace of hearts next to achieve the same result.

Finally, if West had the king of hearts, leading a heart toward the Q-J-7 would also limit the defense to one trump trick.

It is true that if West had led a club initially, or if East had shifted to his singleton club at trick two, the contract could always have been defeated — but that’s another story.

Tomorrow >> Famous Hand.

— Steve Becker