In his new book, “Tricks of the Trade,” published by The Bridge World, Larry Cohen advises us always to avoid a brilliant low-percentage play when there is a high-percentage line, no matter how ordinary.

In today’s deal, you judge well or luckily not to bid the tempting slam. West leads the diamond queen; you win and cash a high trump, finding hearts 1-1. What is your plan to try for an overtrick?

An endplay is just about possible, though highly unlikely. You could eliminate the diamonds and hope that a defender has a singleton club ace. Or perhaps you could sneak one round of clubs past a player with a doubleton ace, then eliminate the diamonds and throw him in with a club, hoping for a favorable spade position.

But why look to such an unlikely layout? You have a much better chance with a more ordinary maneuver. At trick three, lead a low spade toward dummy, just as you would with ace-tripleton.

At least some of the time, an experienced West will duck (smoothly, he hopes), trying to give you a guess. How can West tell that the play of the spade suit isn’t the key to the deal? Ducking may give him a chance to set the game or hold the overtrick if you hold ace-third of spades and guess the suit incorrectly.

Yes, the elimination play is more spectacular, but you must resist the urge. Win the event on the next board, not this one.

Today’s deal is an unusual example of a hand where both opponents are potentially the danger hand, so that either may need to be kept off lead. If that sounds paradoxical, the play to trick one will determine which opponent you are going to need to beware of.

In the auction, North might use New Minor at his second turn to look for an eight-card heart fit. Then again, if his partner has three small hearts, locating a 5-3 heart fit might lead him to the only game that goes down.

Be that as it may, all routes lead to three no-trump, and after a low spade lead from West, South must plan the play carefully. Which spade should he play from dummy? He should put up the queen; if it holds, then East is the danger hand — declarer must keep him off play, or a spade through South’s king could be fatal. In that case declarer would play the king of clubs, then the 10, and let it run. That way, he can set up four club tricks in safety.

When East instead wins the spade ace at trick one and continues with the spade jack, South must hold up the spade king and win the third round. Then he leads the club nine and passes it, willing to lose to East, the safe hand. What declarer cannot afford to do is concede a club to West and see him cash two more spade winners.

Of course, if spades are 4-4, declarer may lose three spade tricks, but he will still make his game even if he does lose a club trick.

Tim Bourke, one of my Australian bridge-playing friends, has a splendid eye for a good deal. He is also an outstanding player who has only been kept from representing Australia because of ill health. But his wife, Margi, has been a regular on the Australian team over the last few decades.

Bourke played this one recently against a computer, finding the way to overcome an extremely unpleasant break. He declared six hearts on the lead of the club king to the ace. A low heart to dummy brought forth the bad news. But he put up the heart queen and correctly decided he needed East to have started with precisely a 3=5=3=2 or 4=5=3=1 shape. He next led the heart three from dummy to the nine and king. Having forced a high heart spot out of East, he cashed dummy’s top diamonds, pitching clubs, then led the heart eight, covered by the 10 and king.

In the six-card ending, there was only one way home. He crossed to a top spade in dummy to ruff a club to hand, then took the spade queen and went back to the spade king. East had been forced to follow to every trick thus far and was down to the J-5 of hearts, while South had only the trump seven left.

However, for the final two tricks, he could lead a minor from dummy and score his heart seven either at this trick or the next. This play, when you score a trick by leading a plain card and over-ruffing your opponent, is called a coup en passant.

Today’s deal shows how a careful declarer can find an unlikely extra chance in a situation where the success or failure of his contract appears to depend on one thing only. Having been given that huge hint, be honest: How would you play six spades on a top heart lead from West?

I’m absolutely confident that a significant percentage of bridge players (hopefully not my readers!) would win the heart and draw trumps, then take an early diamond finesse of the jack. The good news is that the finesse will work; the bad news is that the 4-1 break will leave you helpless.

But what is the hurry to take that finesse? Win the heart lead and draw trumps in three rounds, then cash all the club winners and exit with the second heart. You aren’t giving up anything, but you force the defenders to give you a ruff-sluff or lead diamonds for you. Say West wins the heart and leads a low diamond. You capture East’s card, go to dummy with the diamond king, and have a marked finesse against East’s remaining diamonds. On any other defense, you can discard a diamond from one hand and ruff in the other. Then you can take the diamond finesse against the queen and claim 12 tricks.

This line of play never loses when the contract can be made, and it ensures you can always survive the 4-1 diamond breaks with the queen onside.

It is never a good idea to criticize your opponents’ methods to their faces; behind their backs is another matter. If you make the mistake of commenting unfavorably, then you slip up in the play, they won’t forgive and forget — as today’s deal shows.

South asked about the four-diamond call and feigned disbelief that it was natural rather than a heart raise. But he bid four spades anyway, against which West cashed his singleton diamond ace before switching to a heart.

Declarer won, drew trumps in two rounds, cashed his other top heart and led a low club toward the dummy. The bidding had marked West with the club ace, and declarer had planned to continue the attack on clubs if West followed low. In that case, declarer would have taken the queen and would then have covered East’s jack or ducked the nine on the next round. Then he would have set up the 13th club for the discard he needed.

But West saw the danger and cunningly put in the 10 on the first round of clubs. Now, whatever South tried, East was bound to gain the lead with a club and cash the diamond king for down one. Then West added salt to the wound by pointing out the winning line on the deal. Can you spot it?

Declarer must eliminate hearts and throw West in with his spade queen! (If West unblocks that card, declarer can endplay him with the trump four if he is careful.) Then West must lead clubs or yield a ruff-sluff, and the trick comes back with interest.

Bridge players love to complain, and picking up a complete Yarborough — a hand with no card higher than a nine — offers the perfect opportunity. In the days of whist, Lord Yarborough offered insurance of 1,000 to 1 against the chance of picking up such a hand. Of course, as is usual in such cases, the bookmaker had rigged the calculation in his favor: The true odds are actually 1,827 to 1.

In today’s deal, South bought his Yarborough in dummy, but he managed to exploit its meager assets in an elegant fashion for the equivalent of a trick. See if you can do the same.

When West cashes the heart king and continues with the ace against four spades, you must plan the play. Suppose you ruff, then draw trumps. Now you will find that you are out of trumps, and the defenders will run hearts on you after you have dislodged the club ace.

You must therefore follow the sound principle of trying to set up your side suit when your trump holding is tenuous. Ruff the second heart, then go after clubs, leading the king in the hope that the defenders win their ace and either don’t have a ruff or fail to take it.

After East wins his ace, he plays back another heart. Now comes the second key move. You must not ruff, but instead pitch a diamond from your hand. At this point, dummy will be out of hearts, so dummy’s singleton spade protects you against further forces in hearts.

No matter what the defenders play, you can win and draw trumps, happy to find that they break 4-3. You can next unblock your high clubs and overtake the eight, eventually discarding your last diamond on the fifth club.

Bridge is often unfair, and while pairs often reveals that more than other modes of the game, today’s deal would have been painful for the defense and delicious for declarer under any form of scoring.

The auction went swimmingly for North-South until North’s final pass. He should have known that his combination of singleton diamond and bad hearts facing likely shortage meant he should bid four spades. Of course, had he done so, South would have gone one down quietly in his game for a below-average score.

As it was, West led the diamond 10 to trick one, and declarer was happy to grab a cheap trick in the form of the diamond queen. It then seemed logical to establish a spade trick without letting East in. So declarer laid down the spade king and advanced the spade 10, covered all around as West pitched a diamond.

The bad trump break wasn’t good news, but at least South could see what the fate of four spades would have been. He cashed three top clubs, pitching a spade from hand, and led a heart to his jack and West’s queen. West exited with the ace and another diamond, South won that, returned a diamond and took the last two heart tricks to make his game. Had West exited with a low heart instead of two rounds of diamonds, declarer would have cashed his heart winners and led a low diamond. Whichever defender won that trick would have had to give declarer a trick in his hand in diamonds or a spade in dummy.

After identical auctions, both West players in a team game led a fourth-highest spade two against three no-trump rather than a second-highest spot-card.

At the first table, when declarer played low from dummy, East won with his king and counted the outstanding high cards. As he had 10 points, dummy had 7, and he knew of 20 or so to his left, West could have at most 3 points. There was very little future in spades; one more spade trick would not defeat the contract. East decided to play West for three or four clubs and a red-suit king or the club queen. So, he continued with a low club at trick two.

Declarer won the trick in dummy to run the diamond jack. West took this with the king and continued the attack on clubs. East won his club ace and king and cashed his remaining club to defeat the contract.

At the other table, declarer planned the play in some detail at trick one, counting eight likely tricks in the form of the spade ace, four hearts and three diamonds. While a ninth could come from one of the black suits, declarer saw that if East had the spade king, that player might find the unwelcome shift to a club at trick two.

So declarer took the spade ace at once, then ran the diamond nine. West won the trick with the diamond king, and declarer claimed the contract: The defenders could take a spade and two clubs, but that was all. Declarer would set up a ninth trick from one of the black suits sooner or later.