The first round of the 2016 Vanderbilt Knockout Teams produced an intriguing example of the unsafety play.

You declare four spades on a low diamond lead, after an artificial auction has made South declarer. You might reject the finesse at trick one, I suppose. But you don’t. The diamond goes to the 10 and your queen. With overtricks on the horizon it would be easy to relax – but don’t!

At the table, declarer carefully cashed the spade ace to guard against a 4-0 trump break, Success! West had all four missing spades. A spade to the 10 and queen was followed by a club to the ace and another club to the queen.

East won the club king and got out with a heart to South’s ace. A heart ruff was followed by a club ruff by South. Disaster! West overruffed and exited in hearts.

Now, even if the diamond finesse was working, declarer couldn’t take it. But imagine the diamond finesse is wrong, the spades are 4-0, the clubs 5-2 offside. You are still cold!

Win the diamond queen, cash the spade king to find the bad news (the “safety” unsafety play). Then play the club ace and another club to the queen and king. Win the heart return, cross to the diamond ace and ruff a club with the spade nine.

West overruffs and the defense have a diamond to cash, but they can’t stop you ruffing a club with the spade ace, then finessing in trumps for 10 tricks.

When South opened one spade, North could not jump to four spades immediately, since that would have emphasized distribution not high-cards. So he manufactured a two diamond response, and when South elected to rebid two spades, North jumped to the spade game, expecting a nine-card fit. Thus the cold three no-trump contract was missed.

When West led a trump, South decided to play to ruff a club in dummy to protect against a bad break in that suit. Winning with the spade ace, he tried the effect of ace and another club. When East won and returned a trump declarer took it and played a third club, hoping that if there was a bad split, the hand that won would be out of spades. Alas for declarer, East won and was able to return the last defensive trump, ensuring the defeat of the contract.

When South complained about his bad luck, his partner was unsympathetic; can you see why? So long as all South’s side-suit aces and kings stood up, declarer had a guaranteed line to take 10 tricks, by ruffing in the long (not the short) trump hand. He can win the trump lead in dummy, then cash the red-suit winners, followed by ruffing a diamond high. Now he plays the second heart, which the defenders do best to win, to return a trump.

Declarer wins in dummy, ruffs a heart high, leads a club to dummy’s ace, then ruffs dummy’s last heart with his last high trump. That brings South to nine tricks, and dummy’s master trump represents the 10th trick.

This deal came up in a regional tournament earlier this year. Let’s consider it on the most challenging defense of the club jack lead, which says nothing about holding a higher non-touching honor.

Best is to duck the trick in dummy, win the ace, draw trump then play on hearts. If West can win the heart ace, you may have to guess clubs. But as the cards lie, when East wins the heart ace he can do no better than shift to diamonds. Now you rise with the ace, eliminate the hearts and play a second diamond, hoping it will be East who wins the trick.

The only defense is for West to win the diamond king and play a top club through. At this point you appear to have a guess to make the contract: if clubs are 3-3 with the king wrong you cannot succeed, but if West started life with precisely the doubleton J-10 of clubs you must duck. It might also appear that you have a guess when the cards lie as they do in the diagram, with East having begun with the doubleton club king – but that is an optical illusion.

In the ending you will reach, you can’t go down whatever you do. Even if you misguess and cover the club queen, since East’s club king is doubleton, he is endplayed when he wins the trick. He has no club left to play, and whether he leads a diamond or a heart, you ruff in dummy and pitch your remaining club loser from hand.

In today’s hand, at his second turn South felt he had a little too much to sign off at two hearts, and when North also took an aggressive position, the delicate game was reached. Nonetheless, the competitive auction should have given declarer a blueprint for the play.

Against four hearts West led his singleton diamond. Declarer rose with dummy’s ace, and with the intention of ruffing a club in dummy, he next played dummy’s club queen. East rose with the ace and continued with the diamond king, on which West pitched a spade. Declarer ruffed the subsequent high diamond with the 10 and West thoughtfully discarded another spade. The club king was cashed and a third club was ruffed in dummy. Then came the heart nine – and again West correctly withheld the trump ace, since the dummy’s five of trumps would have protected declarer from being forced by a fourth round of clubs.

These maneuvers ensured the defeat of South’s game; if declarer played another trump, West would win and force him with a club, to promote a second trump trick for the defense. And if South played on spades, West could ruff the third round, with the heart ace still to come.

So what went wrong? South should have known that West had started with exactly four spades, and therefore East held three. So, South’s correct sequence of plays was to cash his three spade tricks after winning the diamond ace, before West could take any discards. Had South done so, he would have been home free.

While three no-trump has nine top tricks on today’s deal, it was hard for South to reach that contract when missing a club stopper, but with unbiddable extra values. One can see the argument for temporizing with three hearts over the three-club cuebid. But that might get you to no-trump the wrong way up, with a spade lead coming through the exposed king.

Anyway, South faced the prospect of making five diamonds after West led the club king. There was nothing to be gained by ducking the trick – West could have been endplayed later on in the hand, but that would not gain declarer a trick. Instead, the lead had to be taken with dummy’s ace.

Trumps were drawn by cashing the diamond ace, and dummy’s heart king won the third trick. Coming to hand with a trump, South discarded a club from dummy on the heart ace. now after ruffing the last heart in dummy, declarer crossed his fingers (hoping the club jack was to his left) and led a club.

West had to take this trick, of course, or else declarer would avoid losing a club altogether. But now he found himself endplayed, forced either to lead away from the spade ace or to concede a ruff and discard. Either way, declarer would hold his spade losers to one.

Discarding from club length in dummy on the heart ace, rather than pitching a spade, may appear somewhat counter-intuitive. North’s club is not a loser, since it can be ruffed, but getting rid of that card completes the endplay.

With his best hand for months at the rubber bridge table, South criticized his partner’s bidding as soon as he saw dummy.

When South produced his second slam try and North jumped to slam, South could not bid on. But North should have bid six clubs over the five diamond cuebid. Had North done so, and then bid six hearts over six diamonds to show the third round control, his side might have reached the respectable grand slam.

After winning West’s diamond king lead in six spades, South played two top trumps to reveal the bad break. Suddenly there were problems in even the small slam, and declarer continued with heart ace and a heart to the queen. He would have been home if the jack had fallen, or had the suit had divided 3-3, or even if East had had to follow to the second heart. However, as the cards lay, East was able to ruff the heart queen and eventually the defenders came to another trick.

Declarer had mistimed the play badly. With two entries to the table, he should have tackled the hearts by first leading towards the queen. When the second round is led from dummy, it would not have helped East to ruff a loser. So he must discard, and now after winning in hand, South re-enters dummy with the club king for another heart play. Again, East cannot profitably ruff, and dummy still has a trump left to take care of the losing heart. East can overruff but declarer has the rest.

This is a splendid declarer play problem from last summer’s Grand National Teams at the Chicago NABC.

In four spades East wins the diamond lead with the ace, and after some reflection, shifts to the club king. Play on. At the table, South won an early club and played the diamond king. When West ruffed, declarer was out of chances as the cards lay.

The winning line, even seeing all four hands, isn’t that easy to spot. The point is that it is easy to make the hand if diamonds break 5-2; your target is to bring home the game when diamonds are 6-1. After the diamond lead and club shift, you must duck the club king, to cut the defenders’ communications for a trump promotion. Win the next club and play the diamond 10 from hand.

If West pitches, discard dummy’s last club. After losing to the diamond queen, you plan to draw trump and pitch two hearts on the diamond king and the now established jack. If West ruffs in on the diamond 10, overruff, and draw two rounds of trump, ending in hand. The key is that you have forced West to ruff a loser, so now he is out of trump. That lets you cash the diamond king to pitch the club, and you will eventually be able to ruff dummy’s third heart in hand.

The see-saw effect, of determining which suits you want to ruff in hand or dummy, and the challenge of how to neutralize the opponents’ trumps seems especially attractive to me.

In the next deal from the Chicago NABC last summer, you would probably want to play six diamonds, but getting to a 4-4 minor-suit slam with a combined 29-count isn’t easy. And while slam certainly wasn’t cold, it offered the opportunity for careful play. A relatively natural sequence like this one, where North shows a balanced 12-14 then 4-5 in the minors, worked well.

In six diamonds, after a low club lead, it seemed logical to play a cross-ruff. South cashed the club ace, ruffed a club, went to the spade ace, and ruffed a second club, then cashed the high hearts. When East produced an ominous queen, that seemed unlikely to be a false-card unless he had the jack as well, so declarer changed tack. A spade ruff and a club ruff with a high trump reduced everyone down to four cards.

If you now decide to trust the opponents’ carding, you have a guaranteed route to 12 tricks. Play the diamond queen, then the spade jack. When West shows out, the diamond 10 and ace are good for two tricks.

But had West produced the spade queen, you would have discarded dummy’s club loser. In that case, if you believe his earlier carding, East will have started life with precisely 3=2=4=4 pattern. He would have to ruff his partner’s winner and lead into dummy’s diamond tenace at the end.

At the table the opportunity for brilliancy ended when West showed out on the spade, but the swing North-South scored for making slam was a perfectly acceptable alternative.