BRIDGE The danger comes from one side

Oscar Wilde claimed: “An idea that is not dangerous is unworthy of being called an idea at all.”

At the bridge table, the concept of the danger hand arises early in one’s education, but it is more difficult to grasp than one might think.

In this deal, how should South play in four hearts after West leads the spade king, and East signals with the jack?

North’s double was negative, promising four hearts (or five or six if he didn’t have sufficient points to bid two hearts). South was just worth his jump rebid, and North bid game because he was hoping for a double fit in the rounded suits.

The contract is in danger when West has the diamond ace. Then, if East can get on lead to push a diamond through South’s king, the contract will fail. How might East win a trick?

East’s spade jack strongly suggests holding the 10 as well -- play the top of touching honors when you cannot win the trick. So, South must let West’s spade king win the first trick (first critical play).

Let’s suppose West continues with another spade. Declarer wins and leads a low heart (second critical play). If South cashes the heart ace first, West will have the chance to unblock his king, giving East an entry with his heart jack.

What can West do now? If he wins with the heart king, declarer will score 10 tricks via three hearts, the spade ace, a spade ruff in hand and five clubs. If West plays low, South puts up dummy’s queen, then leads a low heart. When East plays the nine, declarer ducks, allowing West to score his king anyway. Tricky!