Declarer is sometimes so certain he’s spotted the best approach to his contract that he often begins to play without stopping to double-check his plan. It is in such situations that a disciplined player restrains his impulses until he first makes sure he’s really following the right path.

For example, take this deal where West led the diamond four against six hearts. South took East’s king with the ace and quickly formulated an endplay. He drew two rounds of trump, then cashed four club tricks, discarding the jack of diamonds. Next, he ruffed dummy’s last diamond and re-entered dummy with a trump to lead a spade toward his hand.

Had East followed low, there would indeed have been a very rapid conclusion after South played the eight to force West to win the trick and concede the contract. But East rudely upset the apple cart when he inserted the nine of spades, after which South had to go down one.

Declarer had essentially the right idea at the start, but he chose the wrong way to achieve his goal. A far better approach — one that is virtually certain to succeed — is to discard the eight of spades on dummy’s fourth club and then play a diamond to the jack.

After West wins with the queen, there is no escape. He must either return a spade into the A-Q or yield a ruff-and-discard by returning a diamond. Either way, the contract is made.

By discarding a spade rather than a diamond on the fourth club, South guarantees a successful outcome if West — as seems highly likely from the play to the first trick — has the queen of diamonds. Even if East unexpectedly turns up with the queen, South still has the spade finesse to fall back on.

Tomorrow: Bidding quiz.