A defender should assume, as a matter of course, that the contract he’s defending against can be defeated. If he does not cultivate this attitude as a regular habit, many opportunities to defeat opposing contracts will pass him by.

Let’s say you’re East on this deal and partner leads the heart four against three notrump. Should you take the ace or withhold it? If you do take the ace, is it better to return a heart, or should you shift to another suit? If you do shift, should it be to a spade or a club?

To find the answers to these questions, you must start by assuming that the contract can be defeated. The next step is to count the number of tricks declarer is sure to make. A quick survey reveals that there are eight of them in dummy consisting of five diamonds, a club and two hearts whether you take the heart ace now or later.

This, in turn, should lead you to conclude that if declarer has the ace of spades, he cannot be defeated. You therefore credit partner with the ace. Once you’ve reached this point, it becomes much easier to answer the questions posed above.

First, you must win the heart at trick one, because if declarer has the K-Q of clubs, he can score a heart, five diamonds and three clubs before your side regains the lead. Second, you should not return a heart for the same reason.

Third, since partner needs to have the spade ace for the contract to be defeated, you must shift to a spade. But you can’t lead just any spade. If you return a low spade and South has Q-x-x, as in the actual deal, he can make the contract by playing low from his hand.

To cater to this possibility, you must return the spade jack to trap South’s queen. Regardless of how declarer proceeds once the jack is led, he cannot stop you from collecting four spade tricks, and the contract is defeated.

Tomorrow: Bidding quiz.