Jacob Bronowski, the mastermind behind the extraordinary “Ascent of Man” series, said, “Knowledge is an unending adventure at the edge of uncertainty.”

In bridge, though, sometimes knowledge will allow someone to play with certainty – as in this deal. How should South play in three no-trump after West leads the spade queen?

South saw that he had seven top tricks: two spades, two diamonds and three clubs. It looked so easy to establish the extra two winners in diamonds. So, after winning the first trick with his spade king, he cashed the diamond ace … and suddenly the contract was unmakable.

Declarer did the best he could by crossing to the dummy with a club to the 10 and leading a low heart toward his hand, but East had seen this position before. He rose with his king and, when he won the trick, returned a spade to establish his partner’s suit while West still had an entry in the heart ace.

That was well defended, but South had a safety play to make his contract a certainty.

At trick two, he leads the diamond three from his hand, planning to cover West’s card with dummy’s 10 (or taking the queen with the king). Here, though, West would discard a club. Now declarer still finesses the 10. East takes the trick and returns a spade, but South wins, plays a club to dummy’s 10, leads a diamond to his eight, and can claim these nine tricks: two spades, four diamonds and three clubs.

Finally, note that if declarer immediately goes to dummy with a club and plays a diamond to his eight, he wins here, but will fail when West has the singleton nine.