At the European Open Championships last year, Cedric Lorenzini played six spades on the lead of a low heart to the 10, East’s queen and a low ruff. He played three rounds of diamonds, ruffed a heart to hand, took the spade ace and led a fourth diamond. West ruffed in, and that was fatal. (Pitching a heart now, and again on the fifth diamond, is better. Declarer ruffs a club to dummy and advances the heart king, which East must duck to set the slam).

As it was, declarer overruffed and led the heart king to pin the jack. West ruffed the fifth diamond, but declarer could discard dummy’s club loser and ruff one club in dummy, pitching the other on the established heart nine.

At trick five, declarer does better to lead the heart king. When East covers with the ace, South ruffs with the queen or jack. Next, he cashes the spade ace and follows with the fourth diamond, giving West a choice of poisons.

If he ruffs low, South overruffs in dummy, ruffs a heart back to hand and plays the last diamond, pitching a club from dummy. South can arrange to cash the club ace, ruff a club and discard a club on the established heart nine.

If West ruffs high to return the spade eight (the best play), declarer wins dummy’s 10 and ruffs out the heart jack. Finally, if West pitches a club or the heart jack, South throws a club from dummy and leads the fifth diamond. Declarer now either scores his trumps separately or sets up the heart nine, if necessary.

Today’s deal from the 2017 European Open Championships shows various declarers at work in a slam. You play six spades (after partner uses Blackwood while showing a club void) on the lead of the diamond three. Let’s have a look at what happened to a variety of careless declarers.

At the first table, declarer received the lead of the diamond three and immediately turned his attention to the trump suit by winning in dummy and calling for the spade 10. That card held the trick, and declarer repeated the finesse. West won this time and played back a club, rather than finding the killing defense of returning a third spade. 12 tricks claimed.

At a second table, West did find the play of a third trump. Declarer won in hand and ruffed a club to set up his 12th trick, but stood no chance to get back to his hand to pull that last trump! One down.

It would have been better when East discarded on the second round of trumps to go up with the ace, ruff a club and play a spade to the eight or jack. It then doesn’t matter when West wins his spade king — he is endplayed since he has the heart queen and is forced to help declarer get back to his hand.

This is vastly inferior to the correct line, however, which is embarrassingly easy — though apparently few declarers found it. Run the diamond lead to your hand and ruff a club, then finesse in spades. Nothing can go wrong unless the cards are so hostile that you are booked for defeat no matter what you do.

On this deal from the 2017 European Open Championships, the bulletin remarked that just because the double-dummy analysis (a computer program called Deep Finesse) tells you something, that doesn’t mean it is “true.” The program tells you what should happen on best play; but how often do you encounter that?

For example, Jovanka Smederevac declared four spades doubled on this deal, where the analysts had indicated that nine tricks were the limit — but no one told declarer!

Smederevac, playing with Matilda Poplilov, received a diamond lead; East won and cashed her heart king, then continued with the heart jack. Smederevac ruffed, led a club to the king, which was ducked, and led a club back. East took her ace but shifted to a low diamond, which turned out to be fatal. Smederevac won her queen, took the spade king, ruffed a diamond to dummy, and cashed the third club to pitch a diamond.

She had reached a four-card ending where dummy had the spade ace, a losing heart and two club winners, while East had three spades and the diamond ace, and South the Q-J-6 of spades and a losing diamond.

When declarer led a club from dummy, East could ruff in with the seven, but declarer could over-ruff, ruff a diamond to dummy, and be in position for the trump coup.

East had needed to notice that declarer has only nine tricks: five spades and four clubs. If you play a trump at every turn, declarer can take diamond ruffs, but in turn you can kill her club tricks by ruffing in.

The European Open Championships at Montecatini Terme, Italy, in June last year featured a week of mixed pairs and teams events. Because it is an open tournament, players come from all around the world, and squads or partnerships can consist of mixed nationalities.

David Berkowitz of the U.S. was playing with his wife Lisa, with teammates Jan and Aida Jansma from the Netherlands, and David was full of praise for his teammates’ effort on defense here.

Both rooms played four hearts, and both defenders in the West seat led their singleton club, but Lisa Berkowitz brought home 10 tricks easily enough in the closed room. Here is what happened at our featured table, though.

Declarer won the club lead in hand and ruffed a diamond, East giving count in the process. Declarer next led the heart queen, and Aida ducked this to Jan, who put the spade king on the table! Declarer was forced to try to cash two spades immediately to pitch his club loser. Next, he led a third spade from dummy, and East took the opportunity to ruff high as declarer discarded a club. But that let East give her partner the club ruff to set the hand.

Note that if East covers the first trump, this defense will not work. Similarly, if West shifts to a diamond or a low spade when in with the heart ace, declarer can win in hand and lead a second trump, preventing the defenders from taking their trumps separately.

The European Open Championships allow anyone to enter, and cross-national partnerships and teams are permitted.

Last year the championship was held in Montecatini Terme, Italy, and all this week’s deals come from that event. Today’s deal features a clash between Norwegian and Austrian squads. This was a nice auction to a sensible spot.

In the other room, Terje Aa passed the West hand after a strong club to his right, then bid up to four spades on his own. Since South had shown both his suits, North was persuaded to bid on to five hearts over four spades. Unluckily for his partnership, while declarer does not appear to need the club finesse in that contract, repeated spade leads promoted the heart nine into the setting trick, so five hearts went quietly one down.

At our featured table, South appeared to have found himself in a contract where there was no home for the club loser, but things did not work out that way. Declarer in five diamonds doubled, Petter Tondel, won the spade ace and ruffed a spade, overtook a trump to dummy to ruff a spade, then drew the last trump and took a heart finesse of the jack.

If Andreas Babsch, West, cashed the queen and ace, he would then have to open up clubs, so he won his heart ace and returned the queen, hoping his partner had the jack. (Of course, declarer would have then ducked the second heart.) Whatever he did, declarer had 11 tricks and 12 IMPs.

The NEC tournament in Japan was recently won by a squad made up of one pair from Australia and one from New Zealand. In the finals, Tony Nunn from the winning Down Under team had to work very hard to generate a small swing for his side.

In one room, with two spades relatively comfortable for East-West, the Down Under team had sold out to one no-trump after West had shown the majors over a strong club.

Against one no-trump, the defenders led a spade to the queen and king; the spade nine came back and was covered and ducked. The defense could now take their four spades and two aces, but declarer had his seven tricks.

In our featured room, Tony Nunn played in three clubs after the auction shown, and West found the thoughtful lead of the heart ace and a second heart. Nunn won and played a trump to dummy, which was ducked, and a second trump to hand. When West discarded, declarer played a third trump to East, who led a spade to his partner for the heart ruff.

East now found the diamond shift, and Nunn read the position perfectly when he won in dummy and cashed one more trump. East was now subjected to an unusual squeeze: He chose to pitch a spade, so declarer came to hand with a diamond and ruffed out the spade king, with a diamond entry left in hand to cash his spade winner. Had East pitched a diamond, that suit would have run for declarer.

Making 110 was worth 1 hard-earned IMP.

Today’s deal has a relatively simple theme, but the answer is one that might surprise some of my readers. North may have done too much here, to reach slam. While he does have all four aces, he should have taken second- and third-round controls into account as well, and in this case he has no idea where any spade losers may be discarded.

When the spade king is led to the ace, declarer has to find a way to take care of his spade losers, not to mention the club queen. Which defender should you play for the missing club honor?

After winning the heart ace, king and jack, declarer has to imagine a situation where he can achieve an endplay after extracting the clubs. For that situation to arise, declarer will need to find East having begun with a singleton spade. Given East’s known singleton heart, South must hope that East originally had a 1-1-7-4 shape. So, after cashing the club ace, declarer leads out the club jack, covered by the queen and king.

Then after leading the diamond three to dummy’s ace, declarer cashes two more club tricks with the aid of the marked finesse. At this point, he can lead the diamond queen from hand, throwing a spade from dummy. When East takes the trick, he has only diamonds left to lead, and dummy’s other spade disappears when declarer ruffs the diamond return in hand.

Notice that it is key to lead the club jack from dummy and not to lead low to the 10 on the second round of that suit.

Today’s deal sees North with a promising hand for slam when his partner opens the bidding. However, the one-no-trump rebid persuades North to look no higher than three no-trump. He certainly has no reason to assume that game will be as delicate as it actually turns out to be.

When West leads his fourth-best diamond, the fate of the contract hinges on declarer’s play to the first trick. He should reason that West is relatively unlikely to have led low from a suit headed by all three of the king, queen and 10, so one of those honors must be held by East. If this is so, and the suit divides 4-3, the defenders will have three tricks in diamonds, but no more.

If diamonds break 5-2, the play of the ace may well block the run of the suit for the defense. South’s correct play, therefore, is to go up with the ace in dummy. This play does not lose even if West has led from both the king and queen, because the fact that the 10 would then be doubleton in East’s hand will prevent the run of four tricks. Declarer must still exercise caution; if he next finesses in clubs, the defenders can unscramble their six winners.

Instead, declarer must unblock spades and go after hearts at once, since he needs no more than two tricks in that suit to make his game.

West can win with the heart ace, but his side can take no more than two diamond tricks, even if East has unblocked his king at the first trick.

This deal (with a slight alteration of the heart honors) came up in the Common Game in December last year. Pretty much everyone would have bid the North-South cards to three no-trump; North has just enough to use Stayman and invite game, since if partner has a heart fit or a maximum, there should be decent play for game.

The opening lead gives you grounds for optimism as declarer. The club 10 comes around to your queen, and now it seems natural to go after diamonds. Beware, though! If you play the ace and another diamond, the defenders can clear the clubs and remove your last sure entry to hand. If the defenders duck the first spade and win the next, then cash their club winner, West can exit in hearts and collect the fifth trick for their side.

A much better line is to lead the diamond eight to the queen at trick two. At the table where I was involved, East won her diamond king and continued clubs, but declarer could simply drive out the spade ace and come to nine tricks painlessly enough.

Had East ducked the diamond king, South would next go after spades by running the jack, then leading a spade to the king. The defenders can still make life awkward by winning the second spade and returning a club, but the fall of the spade 10 and the fact that hearts are 3-3 allows you to come home against any defense. You win the third club, cash the remaining top spade to pitch a heart, and set up diamonds, leaving the defenders with two clubs, one spade and one diamond trick.