This was the most intriguing flat board from the 2001 World Championship match between Italy and USA, where in each room South reached an apparently hopeless slam. Consider how it came home at both tables before I let you in on the secret.

Lorenzo Lauria and Alfredo Versace bid the hand as shown here. North first showed a sound spade raise. Then the auction escalated fast, with Lauria’s final jump to slam on the pushy side — but why shouldn’t partner have had the diamond 10?

As you can see, making 12 tricks requires you to lose just one diamond trick. Playing for both the king and queen to be onside seems obvious — but will not work today.

However, both Versace and Bob Hamman had heard West bid clubs. Both won the club lead and led a diamond at once. When West followed low, they decided to go up with the diamond ace. Then, they cashed the top hearts and ruffed a heart, ruffed a club, ruffed a heart, and ruffed a club. This eliminated the clubs and hearts from both hand and dummy.

At this point, both declarers drew precisely one round of trumps and exited with a diamond. In the three-card ending, West was left with only clubs to lead. On the forced ruff-and-discard, dummy could take the ruff, and declarer the discard. Contract made, for a remarkable flat board.

Had either West managed the spectacular play of unblocking the diamond king on the first round of the suit, the slam would have been defeated.

On today’s deal, suggested by Michael Rosenberg, North-South reach the normal spade game, but even with the hands fitting well, finding a “sure tricks” line is difficult.

You might reasonably assume this was one of those textbook hands where after cashing the spade ace, you cross to dummy in hearts (which the defenders must duck), then lead a spade to the jack when East follows. This way, you have a re-entry to dummy in spades for the 13th heart if trumps are 2-2, or trumps will play for no losers if they are 3-1.

Alas for you, it is West who has the spade length. Now, when the heart ace is held up, you will have no way to pick the club suit, since the defenders can exit in diamonds at their every opportunity. A slight improvement would be to ruff a diamond at trick two and follow the same plan, which might give you a chance to make on the actual layout.

The best line, though, is to win the diamond ace and ruff a diamond, take the spade ace, lead a heart to the jack (which must be ducked) and ruff a diamond. Next, lead the heart king. If the defenders duck, play another heart. Should they take a heart ruff at any stage, you have a sure discard coming on the hearts, plus a trump entry to reach it.

As the cards lie, East has to choose between providing you with an entry to dummy’s long heart and being endplayed to lead into the split tenace in clubs or give you a ruff-and-sluff via a diamond exit.

South demonstrated how much his side-suit shape was worth when he pushed to game opposite a simple raise.

At trick one, declarer realized that he might need to bring the clubs in without loss, since even if he could score three diamond ruffs in hand, he wouldn’t have 10 tricks. However, another, better approach might be to set up dummy’s diamonds instead.

So South won the second heart and led the diamond nine to dummy’s queen, in an attempt to ruff down honor-third diamonds on his left. He would also succeed against East holding aceking-third. East took his ace and forced dummy with a heart. Then declarer ruffed a diamond and switched horses by playing the trump ace and king and another trump.

The danger in ruffing another diamond was that if the king did not come down, declarer would need to bring the clubs in. By conceding a trump trick at this stage, he retained the chance of ruffing the diamond king, should the club queen be onside, but it also increased his chances of squeezing the defenders.

(Declarer could not afford to ruff a diamond, then give up a spade; East might win and run hearts.)

Had West taken the third spade, he would have had to open up clubs for declarer and leave him in good shape. As it was, East took the third trump and continued the heart force. However, that was too much for West to bear. He had already let go of a diamond and now had to spare a club. Declarer could then finesse the club jack and run the suit.

Had West started by opening one club rather than a Precision diamond, his opponents probably would have been unable to locate clubs. They would have played three no-trump and would surely have gone down.

As it was, South could bid a natural and forcing two clubs over North’s one-spade overcall. When he caught a raise, he gambled on five clubs, since his clubs seemed too slow to set up in three no-trump.

Declarer won West’s lead of the heart queen in hand and saw drawings trump could wait; he instead had to work on shedding his second diamond loser on a spade. He cashed the spade king and ruffed a heart to dummy. The spade ace and a spade ruff followed.

If declarer had then crossed to the club ace before ruffing both hearts, he would have risked conceding an unwelcome over-ruff on the fourth spade. West would then have been able to draw dummy’s last trump, leaving declarer an entry (and thus a trick) short.

Instead, South ruffed the heart king back to table, and when he took his second spade ruff, it did not matter which defender had the long spades. It was East who had the 13th spade, so West was in a position to over-ruff on the fourth round of clubs and attack diamonds, but declarer remained in control. South was able to reach dummy with the club ace and pitch his last diamond on the spade nine, losing just two trump tricks in total.

This was another deal from a local teams game in which different approaches by the two declarers yielded a swing. Against four hearts, the lead was the same at both tables: the diamond 10.

At the first table, declarer flew up with the ace while East played an encouraging six. Declarer then crossed to hand with a top trump. After returning to dummy with the club 10, South finessed the heart jack. West won, and since his side needed at least one diamond trick, he continued with the diamond three to try to give count in the suit. East won and carefully shifted to the spade king, then cashed another spade to defeat the contract.

At the second table, declarer also won the first trick. Then he cashed the heart tops before playing on clubs. When the third round of clubs was not ruffed, he was able to discard his remaining diamond on a good club. West ruffed in with the trump queen and exited with a diamond, but a spade ruff in dummy was the tenth trick.

What are the odds for each approach? Both plans would succeed if the heart queen appeared singleton or doubleton from East. Otherwise, the first approach makes the contract on just half of the 3-2 breaks, about a third of the time. The second declarer succeeds when there is a doubleton trump queen on his left, but also when the hand with three trumps has at least three clubs. This has just short of a 5050 chance of bringing the contract home, making it the plan to choose.

Both tables in a local teams game reached four spades on the opening lead of the heart jack. Both Souths saw that if trumps were 2-2, 10 tricks would be easy; if they were 4-0, impossible. Each declarer won the lead in dummy and, to protect against a 3-1 break, crossed to hand with the trump ace to lead a low diamond toward the queen.

Both Wests rose with the diamond king and then played the trump queen. One declarer won his king and led a low diamond to dummy’s queen. He continued with the club ace and another club. East won with the jack and exited with a low heart, West’s 10 forcing dummy’s king. When declarer tried to return to hand with a club ruff, West over-ruffed and cashed a heart for the setting trick.

At the other table, when East discarded on the trump queen, declarer saw the danger of taking the king. It would leave him with no fast entry back to hand after unblocking the diamond queen. So he let the spade queen hold. If West continued with the spade jack, declarer could win, cash the diamond queen and eventually return to hand with a club ruff to discard a heart on the diamond ace.

When West instead shifted back to the heart 10, declarer won his king, cashed the diamond queen and came to hand with a trump. Now he could discard a heart on the diamond ace and ruff a heart. Declarer had 10 tricks — four trumps, two hearts, a heart ruff, two diamonds and the club ace.

Suit preference can come on opening lead, but not often. Take the following problem, and assume you hold the East hand.

Consider the auction and ask yourself whether you should pass at your final turn. I agree that this is the normal action, but since you expect you can take a club ruff, put partner in with an ace, then take a second ruff, you might choose to gamble and make a Lightner double.

On the lead of the club five, you ruff away dummy’s ace as declarer produces the seven. Now you must ask: Did partner start with the 5-3-2 in clubs, or is the five his smallest in that suit? If you guess incorrectly which red ace partner holds and partner has no trump trick, declarer may get to discard his red-suit loser on the clubs after drawing trumps.

When Bob Hamman was on lead as West here, he saw that the opening lead of the club queen would be a far clearer suit-preference signal than a wishy-washy five. While leading an unsupported queen might seem dangerous, once you have decided to lead a club, you are never going to score a later trick in the suit no matter which one you choose, so you might as well help partner as much as you can.

After East’s heart return, you will succeed in putting partner in to secure a second ruff and collect 300. But playing back a diamond would allow declarer to win his ace. He might then guess to cash the spade ace and throw his hearts on dummy’s minor-suit winners — and actually make his contract!

The more unreadable the signal partner receives, the quieter the suit-preference message you should be sending. That is the simple face of suit preference; alas, life is rarely so straightforward. Consider today’s deal.

Defending against three hearts as West, you elect to lead a top spade, since you do not care to guess which minor suit to broach. That works out well enough. Dummy plays low, and partner takes the spade ace as declarer produces the five. Then he follows with the spade king as South contributes the two, followed by the spade four for you to ruff, as declarer plays the seven. What now?

The defense to beat the contract is for you to lead a diamond to partner, who can play a fourth spade and promote your heart jack. But how do you know which minor you should lead? Don’t clubs look just as attractive as diamonds, and didn’t partner play his low spade for you to ruff? No! The spade four was suit preference for diamonds — from time to time, the gods of bridge require you to do your bit: in this case, to remember that the spade three had not put in an appearance.

However, that was not the big clue. Partner hit you over the head at tricks one and two when he won the spade ace, then king in unnatural order as suit preference for diamonds (the normal play being king, then ace). Sometimes, one has to improvise suit preference, and a thoughtful partner would foresee the problems in making a small card look big.

As Thomas Gray remarked, “Full many a flower is born to blush unseen.” Today’s deal might have slipped through the cracks if Steve and Betty Bloom’s teammate had not been able to rectify that particular error by providing the Daily Bulletin with details of their prowess at a Gold Coast Congress almost a decade ago.

When Betty led the club 10 against four spades, declarer Sartaj Hans knew that he was in the wrong spot, caused by North failing to bid spades at his first turn. Worse, he could divine that there would be spade ruffs in the offing, not to mention the prospect of a diamond shift from East.

He put up dummy’s club jack and took Steve’s queen in hand, then drew trumps and played on spades. East had had two chances to send a signal. First, he followed up the line in trump (suit preference for the lower suit, here clubs), then he pitched a discouraging diamond nine on the first spade, followed by the diamond two for further suit preference.

Betty got the message. When she took her spade ace on the third round, she underled her clubs, advancing her smallest. Steve overtook her seven with his eight to make the killing diamond shift, and that produced the desired result of one down.

This was an absolute top for East-West; at all the rest of the tables in the main final, 10 tricks were taken in spades or hearts by North-South. (Interestingly, that was the case even when North was declarer, so that a diamond lead would have beaten four spades).