Consider the fate of the likely final contract of four hearts on this deal from the Politiken World Pairs.

On a minor-suit lead, declarer can simply win and take a heart finesse. The best defense now is to shift to spades, but South wins the king, gives up a heart, and now has 10 tricks.

So a spade lead must be best for the defense. What happens if declarer puts up the king after a deceptive low spade lead, then leads a trump? This is what happened when Jaggy Shivsdasani of India was declarer.

Larry Cohen, East, won his heart ace and thoughtfully continued with the spade jack. (He was known to hold the queen from the earlier play in the suit, so he wanted to make sure his partner knew what was going on.) Steve Weinstein (West) overtook the jack and played a third spade. This forced declarer to ruff, then cross to dummy in diamonds and lead a low heart, putting in the jack when East discarded.

Declarer was all set to concede one trump and claim the rest, but Weinstein ducked his trump queen! Now declarer could cash the heart king and play on diamonds, but West could ruff the third round and exit with a spade, leaving declarer with a losing club for down one.

If declarer had played on diamonds without cashing the trump king, West would again have ruffed the third diamond and exited with the trump queen. Cut off from dummy forever, declarer would eventually have had to surrender a club to East.

This deal is one of my favorite defensive problems, despite my being on the wrong end of it. (I sat East when it came in a long-ago Vanderbilt match.)

Put yourself in the West seat. Your partner opens one club in second seat, and you end up defending three spades — you don’t have to like it, but since four hearts your way on a spade lead would not have come home, at least you now have a chance for a plus score.

Against three spades, you lead your singleton club, and partner takes his ace as declarer follows with the six. Partner returns the club eight, declarer produces the king, and you ruff. What next?

Declarer’s shape is virtually known to be 6-2 in the black suits. Given that, you can set the contract for sure if declarer is 6-2-3-2 (partner has a spade trick, you have a heart trick plus the diamond ace, and you already have two club tricks in the bag). And if partner has no spade honor, he certainly has at least one diamond trick.

But what if your partner’s hand consists of a 4-2-2-5 pattern with the club honors, the spade ace and the diamond jack?

This would mean that declarer will pull through by squashing both your spade jack and partner’s diamond jack — unless you find the low diamond switch at trick three. Then your partner can arrange a diamond ruff when in with his trump winner. This was indeed the actual layout; alas, the rationale for the diamond switch only emerged in the post mortem.

Today’s deal sees a contract of four spades that looks easy to defeat, but where the fate of the contract swung back and forth before the result was finally reached.

North-South were playing the simple spade raise as mildly constructive, so South felt he had just enough for a game try. In context, North’s club spots looked like they should be useful, so he bid game, reaching a contract that rated to have at least four top losers most of the time. But West was not in on the game; he made his natural lead of the diamond 10. Declarer won in hand and had only to cash his top trumps, take his discard on the diamonds and give up three tricks. What could go wrong?

At trick two, South cashed the spade ace, and East craftily dropped the jack. Declarer delayed his trump guess, taking the three top diamonds, then playing a club to his king. When it held, he led a spade to the 10. Disaster! East won with his jack, led a low heart to his partner and ruffed the fourth diamond with the nine, then cashed the club ace for down one.

In retrospect, did declarer do anything terrible? Had no spade honor appeared at trick two, cashing the top spades early would have protected declarer against the same hand being short in both spades and diamonds. Maybe South could have led the fourth diamond to discard the heart loser instead of playing on clubs, but that course would have carried risks of its own.

In action on today’s hand is Zia Mahmood, playing in the 1999 U.S. Spingold Teams. After finding an unhelpful trump division, he took full advantage of the inferences available from the bidding to bring home his five-level contract.

After Mahmood, South, opened one heart, West doubled for take-out and North redoubled. East bid two spades, and Mahmood jumped to four hearts. West now bid four spades (a contract that makes), but Mahmood bid on, making a move toward slam; however, the partnership came to rest in five hearts.

The defenders began by cashing two spade tricks, then switched to a diamond. South took his ace and played the heart ace, discovering that East held the balance of the trumps. Zia’s next move was to finesse the club 10. When it held, he cashed the ace, discarding a diamond, then played the king. East ruffed, and declarer over-ruffed, then drew the outstanding trump and returned to dummy on the third round of trumps to pitch his last diamond on the club queen.

Why the spectacular finesse of the club 10? Zia had noticed from the bidding that West was likely to have at least four cards in each minor, especially after he had shown out in hearts. If he had simply played clubs from the top and East had ruffed the third (as he would have), declarer would have needed two further entries to dummy: one to set up a club winner and a second to cash it for the last diamond discard. And those entries would not have been there.

On this deal from an Open Pairs event a few years ago, Barnet Shenkin, formerly of Scotland, was the hero. He was playing with another Scottish expatriate, Sam Levinson.

Against four spades, West led the diamond king to Shenkin’s ace, and declarer played the spade king at trick two to East’s ace. Next came the diamond jack, followed by a third round of the suit, ruffed by Shenkin. Declarer got the bad news in trumps when he cashed the spade queen. Undaunted, he continued with a heart to dummy’s king (it would not have profited West to ruff a loser), followed by a club to his jack.

Shenkin then took the club ace and played a spade to dummy’s nine. East was already starting to feel the pressure, and it became unbearable when Shenkin cashed the spade jack.

In the four-card ending, what was East to do? A heart discard was out of the question, so he had to let go of a club. Shenkin then exited with the club queen, putting East on play in the two-card ending and forcing him to lead from his Q-10 of hearts into the tenace in dummy.

Did you notice the defensive resource? Shenkin remarked afterward that maybe he should have ducked the first trick to cut the defenders’ communications. Had East won the spade ace and given his partner a ruff by leading a suit-preference heart 10, West could then have underled his diamonds and received a second ruff.

Today’s deal should lead in a straightforward fashion to a contract of four hearts, but North’s rebid does raise a question of theory. After opening one spade and hearing a response of two hearts, should North make a splinter jump to four diamonds, showing heart support and a singleton diamond, or does that call promise some extras, either in shape or high cards? You can certainly make the argument that North should simply raise hearts and is not worth the splinter raise, but either way, South should avoid going past four hearts.

In four hearts, declarer’s best play is a simple crossruff. He needs only eight trump tricks besides the two major aces, and even if West leads a trump he can make his game — but he needs to be careful.

After the low heart lead, declarer needs to ruff with his small trumps. The ruffs in dummy (on the second and third rounds of diamonds) are relatively safe, but the spade ruffs in hand carry more jeopardy. So declarer must play the heart jack or king at trick one.

The play continues with the diamond ace and a diamond ruff low, then the spade ace and a spade ruff low. Then comes a diamond ruff with the heart six, and finally declarer can play a high cross-ruff to come to 10 tricks.

Try running the lead to your hand, or fail to take the first two diamond ruffs plus first spade low, and you will go down. So the hand is not as easy as you might think.

Today’s deal saw South take a flyer at four spades, partly because he was not sure what his opponents could make, and partly because it was hard to guess what his partner’s hearts would offer. Facing nothing in hearts, four spades could be cold; facing heart honors, maybe he would get lucky and find the opponents would lead the suit so he could take quick discards.

West did indeed lead hearts, and dummy was about as bad in the majors as it was possible to imagine. Nonetheless, when the first trick got ruffed, East could immediately see that the threat of discards coming on the clubs was a real one. How would you suggest he defend after declarer leads the spade jack from hand at trick two?

The answer is that East must go against received wisdom and lead a diamond back into the tenace. The best lead is a low diamond, hoping to find declarer with at least three diamonds, and for West to possess the 10, or at the very least the nine, with declarer misguessing and failing to put up the 10 from his hand.

As the cards lie, East gets in on the second spade to play a second diamond, and then again with the club king to cash out for down one. If East does not shift to a diamond, South’s slow diamond loser goes away on the clubs.

Curiously, the deal is far easier to defend if North is declarer; after a top spade lead from East, he has a natural shift to a low diamond.

When South opens one no-trump, North drives directly to the no-trump game. If North’s diamonds were exchanged with his spades or hearts, he would show his major on the way to three no-trump, to offer a choice of games.

After a spade lead, South must put up dummy’s spade queen, his only chance to win a trick with that card. East covers the queen with the king, and South must hold up his ace twice, hoping to exhaust East of his spades. When East errs by playing a third spade (yes, a club would defeat the game), South wins and is one trick short of his contract. Sooner or later, South needs an additional trick in hearts. But South begins by running four of the diamonds in case the defenders err again or come under real pressure.

South must leave a diamond entry to dummy, since it would be pointless to develop a heart trick if he could not reach it. He lays down the heart ace, then leads a low heart toward dummy. When West plays low, declarer must decide whether to play the queen or the 10 from the dummy.

This may look like a guess, but South actually has no choice. If West had the heart king, he would take it immediately and cash out his good spades. South must therefore assume that East has the heart king. The only hope is to insert dummy’s heart 10, in the hope that West has the jack. When the 10 forces the king, South gets his extra heart trick and his contract.