Deductions by the Defenders

Those of you who have been following these accounts in deductive reasoning may or may not be happy to learn that this is the final installment1. While it might be fatuous to say that the subject matter has been completely exhausted, the plain fact is that it has been worn slightly thin. We began by discussing the avenues of deduction open to declarer, and for the past several articles have been examining how the defenders can gain some measure of compensation by employing some good old deductive reasoning of their own. Here is some more for our East-West friends on this phase of the game:
Suppose that, against a trump contract, your partner fails to lead the suit you have bid. How do you account for that? For one thing, he may have so many cards in the suit that he can see no possibility of establishing tricks in it. Or he may have a holding such as A-x and be unwilling to lead the suit for fear that declarer has the king. Usually it isn’t difficult to decide which is the more likely explanation. Similarly, if, after a competitive bidding sequence in which you side has bid a suit strongly, your partner leads a card in another suit, you can usually assume it is a singleton.
Going one step further, suppose that, in the middle of the play, your partner fails to return the suit you led originally. The layout could be something like this (you are West):

 Dummy
 West ♣ 8 5 4  East
 ♣ Q 9 6 2  ♣ K J 3
 Declarer
♣  A 10 7

You lead the ♣2 against a contract of 1NT and the declarer takes East’s king with the ace. When East gains the lead (in another suit) he may reason that, whatever the layout of the club suit may be, there is no particular need for him to return one at this point: the fact that he holds the jack means that the suit can equally well be continued from your side of the table. East could therefore be justified in taking the position that rather than simply return a club, it would be more constructive to lead a different suit through the declarer.
You and your partner must establish a kind of rapport in this type of situation: if your partner with the East hand, is shrewd enough to make such a shift when the occasion calls for it, you in turn must realize that it is perfectly safe for you to continue clubs when you are in, for East would have done so himself if he hadn’t had the jack.
Many deductions can be made when your partner has to discard on the declarer’s long suit. If his first discard is say, a low heart, it probably means that he wants you to hang on to your hearts while he looks after the other suits, and so forth. Quite often a well-chosen discard will indicate a player’s exact holding in a suit. For example:
Dummy
A K 6 4
Declarer is playing at 4 and your partner who has to make an early discard, divests himself of the J. This play could have only been made from the J-10-9-x-x, and therefore you know at once how many tricks declarer can take in the suit. You also know that you can discard freely from a holding such as Q-x-x.
Suppose you are East in the next situation:

 Dummy
♣ K 7 4  East
♣ 9

South, who has bid clubs once, is playing the hand at 3NT. At some point he leads a club to the king (your partner playing the three) and returns a club, going up with the ace when you discard. Your partner plays the jack under the ace. What do you make of that?
The jack surely isn’t your partner’s last club, as this would give declarer seven of them. You should therefore deduce that your partner began life with the J-10-x-x-(x), and has played the jack to tell you that South cannot run the suit without a loss*. This information will help you with you with your next discard should declarer continue the suit.
*Some players prefer to treat the play of the jack (or any unnecessary high card) in this situation as a suit preference signal.
When partners can rely on each other to make the proper deductions on defense, they can often help themselves to come up with the right answer in very difficult situations. Witness the following deal:

♠ J 10 9 4
A Q 10 3 2
Q J 8
♣ 2
♠ A ♠ Q 8 3
J 9 6 5 8 7
A K 10 4 9 7 5
♣ J 7 5 4 ♣ Q 10 9 6 3
♠ K 7 6 5 2
K 4
6 3 2
♣ A K 8
South West North East
1♠ Dbl Redbl 2♣
Pass Pass 3♠ Pass
4♠ All Pass

To beat 4♠ in this deal, West must begin by leading the A K x. When declarer wins the third round in dummy, leads the ♠J and lets it ride, a fourth diamond forces South to capitulate. If dummy does not ruff high, East’s trump eight will force the king, while if dummy ruffs with the diamond with the 10, East simply refuses to overruff and waits to collect a trick with the Q-8.
The question is whether this difficult defense is really attainable in practical play, and the answer is that West might easily stumble upon it if, when the K is led, East make the key play of dropping the 9-spot rather than the 5. (After all, East can see that it cannot be right to shift at this point.)
From West’s point of view the nine is clearly the beginning of an echo, so he proceeds to cash the A, on which East drops the five, and continues with a third diamond.
It is to be hoped that the shock of seeing East follow suit to this trick will not do irreparable harm to West’s faculties. If he does manage to recover in time, he will hit upon the defense previously described, and succeed in defeating the contract.
Finally, here is a hand that illustrates the heights to which a pair of really sleuthlike defenders can rise in this game. Assume you have the East cards:

 Dlr: South ♠ J
 Vul: N-S 7 3
Q 10 8 7 4 3
♣ K Q 8 6
♠ 7 6 4 2
A 10 9 5
6 2
♣ J 7 4
South West North East
1♠ 2 Pass 3
4♠ 5 5♠ All Pass

Against South’s contract of 5♠, your partner leads the K, on which you play the 10. His next lead is a low heart and you win with the ace, South following suit.
It is readily apparent that to beat this contract West has got to have the ♣A or the A (and on the bidding is almost certain to have one of them). It is also equally clear that if you return the wrong suit, the contract may be made. Why, then, did your partner not save you a headache by simply cashing his ace before leading a second heart?
There’s really only one logical explanation and you can see the nature of your partner’s problem if you take a look at the complete deal:

Dlr: South ♠ J
Vul: N-S 7 3
Q 10 8 7 4 3
♣ K Q 8 6
♠ 9 ♠ 7 6 4 2
K Q J 6 4 A 10 9 5
J 9 6 2
♣ A 10 9 3 2 ♣ J 7 4
♠ A K Q 10 8 5 3
8 2
A K 5
♣ 5

After winning the first trick with the heart king, West has to consider the possibility that South is void of clubs and has the A x x. In this case, if West tries to cash the ♣A, South will ruff, cross to the ♠J, and dump his losing diamonds on the ♣K Q. To avoid this ghastly possibility, West leads a low heart at trick two so that you can return a club without danger.
Note that the situation would be quite different if West had the A instead of the ♣A. In this case, West would have no qualms about laying his ace down at trick two (or cashing the Q first and then leading the A). True, South might ruff, but in that case nothing would be lost because, with you holding the king, diamonds would not become established.

1A five-part series, Dormer on Discovery, will appear on BridgeFeed soon.