Deductions From Opponent's Bidding

A noted expert, renowned for his cautious bidding methods, was once asked how many grand slams he had reached in the course of his career where the bidding had enabled him to be absolutely certain of making the contract. He thought deeply and then replied, “only one,” adding, as an afterthought, “. . . and it went down.”
I mention this only to make the point that if an expert cannot rely 100% on the accuracy of his own partnership bidding — and the annals of bridge show conculsively that he cannot — then it stands to reason that more than a few of the deductions that you make about the meaning of your opponents’ bidding are bound to prove wrong.
Nevertheless, making deductions — and acting fearlessly upon them — is something you simply must do. When tackling a suit combination after a contested auction you have to ask yourself not “What is the normal percentage play with this combination?” but “In view of the bidding, what is the most likely distribution of the opponents’ cards?”
Suppose you have nine trumps in the combined hands, missing the queen, as in this familiar situation:

 Dummy ♠ A 10 7 4 Declarer ♠ K J 5 3 2

The normal percentage play, of course, is to lay down the A-K. But suppose that one opponent or the other has overcalled in clubs: in this case you should tend to expect the partner of the overcaller to be long in the suits other than clubs, and therefore youshould play him to have the Q-x-x of spades.
This type of deduction is most useful when the mathematical difference between two lines of play is slight. Thus, when you are missing four trumps, including the queen, playing to drop the queen is only very slightly better in mathematical sense than taking a finesse against it.
When the card you are trying to locate is a queen or jack, there is seldom any sound reason to assume that it forms part of the high-card values on which an opponent’s overcall was based. For example:

 Dummy ♦Q 10 5 2 Declarer ♦A K 6

Let’s say East has overcalled in spades. It makes no difference to the soundness of East’s overcall whether he has the jack of diamonds or not, and therefore, needing four tricks from this suit, you should boldly take a third-round finesse with dummy’s tenspot rather than follow normal procedure of playing A-K-Q, as you would after an uncontested auction.
The deductions you can make about suit lengths in the unseen hands are even more precise when an opponent has opened the bidding than when he has merely overcalled. These deductions arise because, by and large, opponents can be expected to follow the normal rules of systematic bidding. A player who opens one spade is clearly unlikely to have as many as four clubs and so on.
A useful tip is that you should always stop and think when a defender who has opened the bidding turns up with a singleton. Very reliable deductions can be made in such cases, sometimes to the extent of revealing the opponent’s complete hand-pattern. For example:

 Dummy ♠ J 9 6 2 ♥ K 6 4 2 ♦ A 10 5 ♣ 10 4 Declarer ♠ 10 8 3 ♥ A J 9 5 ♦ K Q 4 ♣ A J 7

Let’s say you are at 3NT, East having opened the bidding with one club. West leads the ♣2, dummy plays low, East plays the queen and you win the ace.
You are certainly entitled to count on a second trick in clubs and this brings your tally to at least seven winners. The natural suit in which to seek extra tricks is hearts, and East may very well hold the Q-x or Q-x-x. However, before leading a heart to the king and a heart back, it will cost nothing to cash the K-Q of diamonds. This is done merely to see if anything turns up, and in the actual case it does, for East shows up with a singleton diamond.
This, together with the bidding, means that poor old East’s holdings have become virtually public knowledge. He has opened one club on what appears to be a four-card suit (since West’s opening lead would seem to indicate that he has four of them). East would not normally open one club if he held five cards in either of the major suits, and since he has shown up with a singleton diamond his distribution can only be 4-4-1-4. Therefore you do not play the hearts in normal fashion: instead, you lead a heart to the king and then finesse the nine. After forcing out the king of clubs, you cross to the ace of diamonds and take a second finesse in hearts to land 3NT.
If you become declarer after an opponent has made a call that defines his hand-pattern fairly closely — such as one notrump, a takeout double or a preemptive bid — you will invariably be able to figure out quite a lot about the hand. A point to remember about takeout doubles is that the fewer honor cards you are missing, the more likely is your opponent’s double to be based on a classic three-suited hand such as 4-4-4-1 or 5-4-3-1, with a shortage in the suit doubled. If you are missing quite a few high cards, however, an opponent’s double may not necessarily be based on classic distribution.
The following deal shows how this type of deduction might help you to resolve a very close decision:

 Dummy ♠ 5 4 3 ♥ A 9 8 7 2 ♦ A J 2 ♣ Q 8 Declarer ♠ A K ♥ Q 6 3 ♦ K Q ♣ J 10 9 7 5 3
 West North East South 1♣ Dbl Rdbl 1♠ 1NT Pass 2NT Pass 3NT All Pass

West leads the queen of spades and East plays the 10. At first sight it seems natural to attack clubs, but then you realize that if East happens to have five spades, the defense will get three spades and two clubs before you can make nine tricks.
If East really does have five spades, your only hope of getting home will be to establish four heart tricks. However, West is bound to have the king of hearts as part of his takeout double, and moreover he is likely to have four cards in that suit.
This last fact, however, raises an interesting possibility: if East’s singleton heart is the 10 or the jack &emdash; which is by no means unlikely — you can get home simply by leading the queen of hearts through West, thereby limiting him to one trick in the suit.
Well then, do you go for the club suit or do you go for the hearts? You’ll agree that the choice is extremely close, and my own way of resolving it would be to try and gauge just how nearly West’s hand is likely to approach a classic hand-pattern for his takeout double.
Suppose first that East-West are vulnerable and North-South are not. In this case I would assume that West is certainly likely to have four cards in both major suits. On this count, therefore, I would plan to establish the clubs rather than the hearts.
On the other hand, if North-South were vulnerable and East-West were not, I would strongly consider the possibility that West has entered the bidding with a 3-4-4-2 hand-pattern. In this case there would be no time to establish clubs and I would return the queen of hearts at trick two.

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