Today’s deal is derived from a hand from a North American Bridge Championship match in San Diego. The defenders’ sidesuit holdings have been edited to make my point more clearly.

When North hears his partner respond one heart, he might believe his hand is too strong for a splinter raise to four diamonds, because slam is almost cold facing nothing more than five hearts to the queen and an ace. Some people would prefer a jump shift to spades before jump-raising hearts. Regardless, South ought to reach six hearts today. Plan the play on a diamond lead.

Here’s what you should not do: Draw trumps. If you win the diamond and play the heart ace and king, maneuvering to get that diamond ruff has suddenly become just a little awkward. You can come back to hand with a third heart, but now if you play the diamond king and ruff a diamond, you will expose yourself to a force in diamonds. And if you play on the black suits, a bad break in either suit might prove fatal.

Instead, simply ruff a diamond high at trick two, then play two more high trumps from dummy. Finish drawing trumps if they break, but when East turns up with length, simply play on clubs. You will succeed unless one hand has a singleton club and four trumps.

If West turns up with trump length and the club ace is ducked for one round, you may have to guess whether to play on clubs or spades. However, East’s early discards will probably help you decide.

After the first final session of the Mitchell Board-a-Match Teams from San Diego last year, Steve Sanborn was full of praise for his wife’s play in four spades doubled … but despite the fact that everybody was supposed to be playing the same deals, nobody else recognized the hand. Steve and Kerri were playing against Dennis Bilde and Giorgio Duboin.

The late John Lowenthal — everyone’s No. 1 choice for “Mad scientist on opening lead” — might have led a red suit at trick one. Bilde, however, looked no further than a top club for his opening salvo. At the sight of dummy, he shifted to a diamond, which went to the three, nine and queen.

Kerri played the spade 10 to the king and ace, won the spade return and ran all the trumps. She had come down to the doubleton ace in each red suit in her hand and the doubleton jack in each red suit in dummy, but what four cards was East to keep?

To keep the diamonds and hearts guarded, Duboin also had to retain two cards in each red suit. Declarer then played the heart ace and another heart; Duboin could win the latter trick, but he was then endplayed to concede the last two tricks in diamonds. Making the doubled game was good for a win on the board.

So why did no one else know the deal? It was board 28 in a 14-table section, but all the other sections had only 13 tables, so they had only played boards one through 26.

In today’s deal from the 2014 European Championships, host nation Croatia faced the favorites and ultimate silver medalists, Monaco.

In one room, South reached the normal contract, despite East’s light third-in-hand opening. After a heart lead, a simple line would be to rely on either the diamond or spade finesse working, by leading to the diamond queen. However, that approach would fail today.

Instead, assume that the contract will always make if the spade finesse works. If it doesn’t, the diamond king will surely be wrong. You cannot avoid the spade loser, but your play in the diamond suit can be tailored to the circumstances of the deal.

So how should you play diamonds for just one loser? The best line is to use the technique first identified and classified as the intra-finesse by Gabriel Chagas.

At trick two, play a small diamond to the eight or nine. East wins with the jack and returns a heart. You ruff the third heart and enter dummy with the club ace, then run the spade 10. West wins the king, you ruff the heart return, and now (though you do not know it) West has longer trumps than you.

But you play the club king and ruff a club, then lead the diamond queen. East covers, and when you play the ace, West’s 10 makes an appearance.

If you read the position, you will leave trumps alone, instead playing out another diamond. Although West can ruff, he must concede the rest whether he plays back a club or a spade.

West’s pre-emptive club raise forces North to commit to game or part-score. When he takes the high road, South buys a dummy where he is apparently doomed to lose a club, two diamonds and a spade in four hearts. However, to make up for the wasted values in clubs and duplication of shape, South can find good luck elsewhere — as long as he plays for it.

When East wins his club ace and shifts to a low diamond, South must put up the king. East has opened the bidding, suggesting he has the diamond ace, and ducking would expose him to a ruff as well as the loss of three tricks in the minors.

South’s king wins as West follows with the queen. South next draws trumps and gives up a diamond, and East must let West win with his jack, or the diamond nine will become established to provide a discard for declarer.

After winning the diamond jack, what can West do? If he shifts to a low spade, that forces East to play the jack. Declarer wins and (if he guesses correctly that spades are breaking rather than diamonds) drives out the master spade, with the defenders’ communications cut. So declarer can cash the long spade to pitch his diamond.

If West instead shifts to the spade 10 or queen, declarer ducks and can now build his spade winner in peace and quiet.

Notice that if the spades in the East and West hands are switched, when West shifts to a low spade at trick six, East must put in the 10!

Against six spades, a trump lead would work best to disrupt dummy’s late entries, and I suppose you can make a good case for it if you consider how weak partner’s hand is likely to be. But few of us would look too far beyond the heart sequence, so South should plan the play after winning with his heart ace at the first trick.

A poor player would pitch his diamond on the heart winner and would end up with two club losers. Meanwhile, an optimist would put all his faith in a diamond break or the convenient fall of a diamond honor. He would cross to dummy to take the diamond finesse and go down.

But the expert will rely on the diamonds breaking no worse than 4-2 — in which case he really doesn’t need any help with the fall of an honor, thanks to dummy’s trump entries.

At trick two, he plays the diamond ace, then the queen. As the cards lie, West must win and can do no better than lead a trump. Declarer wins with dummy’s spade six, underplaying it with his own three, then ruffs a diamond with the spade ace. He leads the spade seven to dummy’s eight, ruffs a diamond with the trump king, and can finally lead the spade nine to the 10. The club losers disappear on the heart king and the good diamond.

Incidentally, after a trump lead, declarer could technically succeed by winning in dummy and running the club jack, covered all around. Then he takes all his hearts and trumps to catch West in a club-diamond squeeze at the end.

After East’s opening bid of one spade, South has something in hand for his overcall of one no-trump. North might now bid game, but he does have terrible spotcards. When he merely invites, South can bid game anyway.

West leads the spade 10, and South sees that he has the top two spades and three hearts, with the club ace providing a sixth trick. South must plan to get his three additional tricks from diamonds, and his only chance is to find the doubleton diamond ace in one opponent’s hand or the other. He must first investigate which opponent has that ace.

Since his side has 26 high-card points between them, there are only 14 points left for East and West. East should have at least 11 of these points to justify his vulnerable opening bid, so he is overwhelmingly likely to hold the missing ace.

So, South wins the first trick with the spade queen and enters dummy with a heart to lead the first diamond from dummy. East plays the diamond nine, and South wins with his king. He must now play back a low diamond and contribute a low diamond from the board, hoping that East will be forced to play the ace. When luck is with declarer and East’s ace pops up, South has succeeded in establishing diamonds for a loss of only one trick.

East can return the spade king, but South can win and run for home with nine winners now.

When the sight of dummy reveals that entries may be at a premium, you must take care to avoid embarrassment. Now that you have been warned, you won’t fall into a heffalump trap, will you?

After a rapid auction to three no-trump, West led the spade queen. Declarer saw she had nine tricks — provided that the clubs brought in the expected five winners.

South ducked the opening lead, more for form’s sake than anything else, then won the spade continuation and reassessed what could go right and what could go wrong.

She noticed that if she played dummy’s clubs from the top and followed in her own hand with small cards, a 3-1 break in clubs would mean that she would be forced to win the fourth round of the suit in hand, blocking communications to the fifth winner. Similarly, if East held all four missing clubs, the contract would be doomed.

But there were two undesirable outcomes that declarer could handle, the first being that if West held all four missing clubs: The situation would still be under control, as long as South retained both her two high clubs (for the possible finesse) and the low one as an entry.

So, at trick three, South led the club seven from hand to dummy’s queen. When everyone followed, she now only had to remember to unblock her two high clubs under the king and ace.

However, if East had shown out, declarer would have been in position to return to hand and finesse against the jack.

The second qualifying session of the Kaplan Blue Ribbon Pairs from San Diego last fall threw up a challenge for the analysts. Debbie Rosenberg posed this problem: What is the optimal contract for North-South on best play and defense?

With the heart finesse working, you can make six no-trump by setting up a club or building a second spade trick, should the opponents lead that suit. But how about seven diamonds, reached after Blackwood and an ask for the trump queen?

The line of play you could follow in six diamonds as North on a trump lead (win the diamond king, cash the club ace and club queen, play a diamond to dummy, take a club ruff high, then draw trumps and eventually take the heart finesse) seems to work.

Ah, but what about an initial heart lead? Your late entry to the heart suit has now gone. But Deep Finesse (the analytical tool that looks at best play by all four hands) still obstinately insists that seven diamonds can be made. Back to the drawing board!

The solution is not intrinsically complex, but the choice of lines makes it hard to spot.

Win the heart jack, ruff a heart, then draw four rounds of trumps to reduce down to a seven-card ending. East is caught in a three-suit squeeze on the last trump. To reduce to fewer than three hearts and four clubs would immediately be fatal. But to retain those cards, East must pitch the spade king. Declarer can unblock clubs, cash the heart ace and king, then finesse in spades.