In the fifth session of the Cavendish pairs, you are faced with a difficult slam decision.

None vul, East deals. As South, you hold:

1♣: 16+ points
2♦: 5+ diamonds, 9+ points, game-forcing. Natural bidding follows.
2NT: 9-11 or 14+ points (with 12-13 and the right shape North would bid 3NT). Likely exactly 3-2-3-5 shape, since responder tends to bid out his shape.

Your call?

Your hand is notrumpish with honors in all the short suits. 3NT is quite likely to be superior to 4♥. Bidding 3NT is quite tempting.

On the other hand, you do have 6 hearts and partner doesn't know that. If you bid 3NT you can never get to 4♥ if that is right, but if you bid 3♥ partner can still bid 3NT or hedge with 3♠ if he thinks 3NT might be better. Partner knows that you know his shape, so both partners will know that a 6-2 heart fit exists.

Another consideration is that partner is unlimited. You assume initially that he is in the 9-11 range, but he might have the 14+ hand. You could be in the slam range. If so, 6♥ could be the best slam if partner has the right sort of hand. If that is the case, you must rebid 3♥. It must be the better choice.

You bid 3♥. The bidding continues:

4D: Q-bid for hearts, slam interest.

Your style is not a control-bidding style. Partner will tend to cue-bid in the suit where he needs help. Also, if partner wanted to give you maneuvering room he could have Q-bid 4♣, even without a club control, in order to leave you a 4♦ last train option.

If you move towards slam, you have available:

4♠: RKC for hearts
4NT, 5♣, 5♦: Asking for a control in spades, clubs, or diamonds respectively
5♥: General invite

Your call?

Partner clearly has the 14+ hand, and you are in the slam zone. You must evaluate your hand in light of what you have already shown.

Your side controls are great, in particular the king of diamonds which is surely working. If partner had bid 4♣ you would certainly be worth a 4♦ last train call. But you don't have that option. If you move toward slam, your must go beyond the 4♥ safety level.

You have a 6-card heart suit, but partner already knows that. The suit is about as bad as can be. Partner will need 2 honors in hearts to make 6♥ a good contract. You are minimal in high card strength. If your ♣K were the ♣Q you might not have opened 1♣. You don't have any singletons. Partner doesn't know this. For all he knows you could be quite distributional. All things considered, it looks like you are on the low side of what you might hold. You really aren't worth any further move at this point. If there is a slam, partner may be able to find another call.

You bid 4♥. The bidding continues:

5♥: General slam try. Partner had the same slam move options available that you had.

If you aren't passing or bidding 6♥, your other bids mean:

5♠ or 6♣: cue-bid, grand slam interest
5NT: Pick a slam
6♦: Offer to play

Your call?

Once more you have to re-evaluate. Your hand is minimal, but you have already told your partner that. He is still interested. Now you must decide how bad your hand really is in the context of minimal hands.

It could be worse. You do have primes. Your diamond holding could be golden. You even have the heart intermediates to guard against a 4-1 heart split. You definitely have an acceptance.

It looks like 6♥ is the best slam. Having a trump suit gives you the potential to set up his long diamonds by ruffing as well as the other flexibility from a trump suit. It seems highly likely that partner has two heart honors, else he probably wouldn't have a further invite. If you had to make the final decision yourself, you would choose 6♥. But you don't have to make that final decision yourself. Suppose partner has something like ♠Kxx ♥Ax ♦AQJxx ♣Qxx. His auction would be quite reasonable, and 6♦ or 6NT are far better contracts than 6♥. Keep in mind that while you know your hand is balanced, partner doesn't know that. It is well worth going that extra mile and bidding 5NT to give him the choice. Most of the time he will choose 6♥, but if he does choose 6♦ or 6NT that is quite likely to be the superior slam.

You choose to bid 6♥, ending the auction.

West leads the ♣3 (3rd and 5th leads).

How do you plan the play?

If the ♥Q isn't doubleton you have 11 winners -- 5 hearts, 2 diamonds, 3 clubs, 1 spade. The twelfth can come from setting up a diamond trick or by taking the spade finesse. Obviously the diamonds should be tried first, since if they don't split appropriately you may be able to fall back on the spade finesse.

A 3-3 diamond split is easy. How about a 4-2 diamond split? You will need 3 entries, 2 to ruff out the diamonds and the third to get back to cash the long diamond. The ♦A itself is the entry for the first ruff, and the ♣Q will be the late entry. You will need one heart entry. This means that you will be able to draw one and only one round of trumps before going after diamonds.

If nothing of interest happens, the plan is as follows: Win the ♣A in hand. Heart to ace. Diamond to king, diamond to ace, diamond ruff, heart to king, diamond ruff, draw trumps, and the ♣Q will be the entry to the good diamond. Assuming the hearts aren't 5-0, this line of play will fail only on a 5-1 diamond split. Even that might be survived if the second round of diamonds is ruffed with a natural trump trick and the ♠K is onside.

What of interest might happen on the first round of hearts to change your plans, and how will your plans change?

If the ♥Q falls on the first round of hearts, you no longer need to set up a diamond trick to make the contract. All you need to do is to cash another heart, get back to your hand, draw trumps, and claim.

If East has 4 small hearts, your safest way back is with a diamond. If East ruffs, he ruffs air, and you still have 2 diamond winners.

If West has 4 small hearts, your safest way back is a spade finesse. Whether it loses to the king or a ruff, West cannot damage you.

If hearts are 5-0, you will not have enough trumps to be able to take advantage of a 4-2 diamond split. However, a 3-3 split can be used, with the spade finesse in reserve.

When West has 5 hearts, it is easy. Cash the second high heart, cross to the ♦K, and knock out his ♥Q. Say West returns a club. You win in hand and draw his trumps, discarding a diamond, a small spade, and the ♠Q from dummy. Then you test the diamonds, and if they don't work you take a spade finesse.

When East has the 5 trumps this won't work, since he can lead a spade when in with his ♥Q and force you to make a premature decision. Therefore, you must risk taking the diamond ruff before knocking out his ♥Q so you find out if the diamonds are 3-3.

What of interest might happen on the first round of diamonds to change your plans, and how will your plans change?

Suppose West plays a diamond honor when you cross to the ♦K.  It might be a singleton. In order to guard against that, you could lead another heart. If they split 3-2 without the queen dropping, you then cross to the ♣K, lead a diamond up (so West can't ruff your winner), and if West has a singleton diamond follow with a ruffing finesse.

Similarly, if East plays a diamond honor it could be a singleton or he could be splitting from QJx. Once again it might be right to draw the second round of trumps and test the diamonds, and if they aren't 3-3 fall back on the spade finesse.

There are pitfalls. For example, suppose West plays the ♦J on the first round of diamonds. You lead a second round of hearts, and both opponents follow small. However, when you cash the ♦A, both opponents follow small. You lead the ♦10, and East follows small. Now what? West might be fooling around with ♦Jx, but he would never play the ♦J under the king looking at that dummy from ♦QJx, would he? So you take the ruffing finesse.

Could West find such a falsecard from QJx? He might. He can deduce from your bidding (no diamond raise ever) and your line of play that you have only a doubleton diamond. He can see you are planning on setting up the diamonds, and that your plan will succeed. So yes, he could find such a falsecard.

The conclusion is that if a diamond honor falls on the first round of diamonds your line of play depends upon your judgment of your opponents. If you don't think they would be up to falsecarding, you should protect against a singleton honor. But if you believe they are good enough to find such a diabolical falsecard, then you should ignore the honor and continue with your original plan.

As it turns out, nothing exciting happens. The cards are as friendly as can be, and you take all the tricks. The full hand is:

West did have ♦QJx, but didn't see the falsecard. It wouldn't have done him any good since you have the ♥J, but he can't know that for sure. If his partner had held the ♥J, the falsecard might have led you astray.

Do you agree with North's bidding?

It looks right on target. He described his shape perfectly. He wasn't quite worth driving to slam. For example, you might have held: ♠AJ ♥J10987x ♦Qx ♣AKJ. With that hand you would have passed the 5♥ invite, and slam would have been poor.

With his actual hand had you bid 5NT he certainly would have picked 6♥, so going the extra mile wouldn't have made any difference. But if he had more in diamonds and less in hearts it could have made a big difference.

Many pairs focus on cue-bidding controls at the 4-level, and then if they have all the suits controlled they try to determine if they have a slam. We use the 4-level to see if we have the strength for slam. If we decide that we do, then we can use RKC if we think keycards are the issue, asking bids if we think controls are the issue, or simply invite if we think a bit more power might be needed.