Dormer on Deduction

Deductions from the opening lead

Last week’s article covered some of the deductions a declarer can draw when playing at a notrump contract. It was pointed out, for example, that many chances for detective work arise simply because it is usual for a defender to lead a long suit. When he doesn’t there has to be a reason, and if you can figure out the reason you have learned a great deal about the unseen hands.
Now let’s consider the deductions that can be drawn from the opening lead against a trump contract. These deductions are of a different order, for against a trump contract defenders do not have such a single-minded objective as that of establishing long cards.
However, we can start with one or two very safe propositions. For example, defenders seldom underlead an ace on opening lead against a trump contract; therefore, if you don’t have the ace of the suit led, you should always assume that the RHO has it.
Another reliable deduction is that when an opponent leads a spot card of high or middle rank, he probably has no honor card in the suit. This knowledge may well save you form eventually or immediately taking a losing finesse in that suit. Say you are declarer on this deal:

♠ A Q 5 4
K J 3
♣ A 5 3 2
♠ K J 10 7 3 2
A 7
10 4
♣ K 8 6
South North
1♠ 3♣
3♠ 4NT
5 5NT
6 6♠

You start life with 11 winners and —in the abstract— appear to have an excellent chance of bringing matters to a favorable conclusion by taking finesses in both hearts and diamonds. If either finesse wins, you are home.
Such would certainly be the simplest way to proceed if you had no information about the defenders’ hands, but in practice it is virtually impossible for a defender to make an opening lead without tipping off his hand to some extent, and we’ll say that in this instance West leads the 9.
It now becomes a moral certainty that East has the queen i that suit, which means you would be wasting your time taking the heart finesse. The wheeze, therefore, is to try to figure out some way of profiting from the expectation that East has the Q, and the strategy that suggests itself is to use the J, not for the purpose of taking a hopeless finesse, but as a means of throwing East into the lead later in the play.
Accordingly, you win the heart opening with the ace and draw opponents’ trump. Next you take the ♣A-K, cash the K and lead the J. You could ruff East’s queen, of course, but instead you discard your last club.
If East happens to have been endowed with only two clubs originally, he will be out of that suit and will thus have to give you the contract outright by returning either a diamond into the A-Q, or a heart, in which case you will make your slam by ruffing in dummy while discarding your losing diamond.
Alternatively, if East began with three clubs, he will be able to return the remaining one, but you will simply ruff this and then discard your losing diamond on dummy’s established club.
Only if East is inconsiderate enough to have begun life with four or more clubs will you be in trouble, and in this case you can still take a diamond finesse.
Now let’s say that West’s opening lead is the 9. This time you would deduce that East had the king of that suit, and you would therefore plan to develop the hand in a similar way, eventually throwing East in with his king after having eliminated the black suits from his hand.
On the other hand, if West led a low heart originally, you would be much more inclined to place him with the queen, and it would then be reasonable to take a finesse in that suit.
Of course, in each and every case described your deduction might turn out to be wrong, but you should not let that discourage you. Bridge is not like tic-tac-toe, where if you play correctly you cannot lose. In the long run you will improve on the normal mathematical chances by attempting the sort of deductions set forth here, even though you cannot be right every time.
The opening lead by a sound defender is always the first step in a long-range plan of defense, and you must try to deduce what the plan is, even if only in general terms — active, passive, forcing or ruffing. For example, it is a basic principle that a defender who tries for a ruff stands a far better chance of succeeding if he hold a winner in the trump suit. Therefore, when a defender plays for ruffs you should tend to assume he has a trump trick.

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

West leads the 7 and East wins with the ace. East returns the 5 and dummy’s nine wins the trick., West following with the tree. How would you continue?
At first it seems that life is just a bowl of cherries, for you can afford to lose a trick to the king of trumps, plus two diamond tricks. However, the whole setup suggests West is aiming to ruff your K, and therefore you have to decide whether to try to discard that card on dummy’s clubs before going any further. Admittedly, there are risks in this line of play also.
Before committing yourself you should review the few clues you have to go on. Diamonds have been bid and supported, and West could have made a safe enough lead in that suit if he wanted to. This suggests that his actual lead of a heart must have looked good to him, and this in turn suggests that he has the K-x-x of trumps. With only K-x, the possibility of a ruff would have looked less appealing to him.
Therefore you should not take the trump finesse, or lay down the A-Q, but should first take three rounds of clubs, discarding the K. Once this succeeds, you can try the spade finesse in complete safety. The full deal may be something like this:

♠ 10 9 5
J 10 9 2
4 3
♣ A Q J 9
♠ K 4 3 ♠ 7 2
7 3 A Q 8 5
A Q 10 9 7 K J 2
♣ 10 8 3 ♣ 6 5 42
♠ A Q J 8 6
K 6 4
8 6 5
♣ K 7

No less valuable than the previous type of deduction are the deductions that arise when a defender is evidently making no attempt to score a ruff. For example:

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

Let’s say West leads the K and East overtakes with the ace. East returns the 6, which you ruff. You cash the A and then lead dummy’s low trump, East following low. The question is, do you finesse the 10?
It seems certain that West held seven diamonds originally, and therefore his distribution is probably 7-3-2-1 (such a hand pattern is far more common than 7-2-2-2). If West had held a singleton in either clubs or spades he probably would have led it in an attempt to gain a ruff; therefore, his singleton is most likely to be in hearts, so you should finesse the 10.
A particularly valuable inference arises when a defender — who is not trying for a ruff — refrains from making what would seem to be the obvious lead of the unbid suit. Suppose your holding in the only unbid suit is x-x in dummy, K-J-x in hand. You should always expect the player on the left, who refused to lead the suit, to hold the ace. If he held the queen — or neither the ace nor the queen — he would certainly have led the suit.
An opening trump lead also tells a story in one way or another, and in this case it is particularly important to recollect the bidding. If only the trump suit has been mentioned, a trump opening is simply a “give-nothing-away” lead, from which you may assume that the opening leader has no strong alternative. He probably has tenace holdings in the plain suits.
When at least two suits have been bid in the course of which the declarer has become marked with a side suit, the lead of a trump by a sound defender conveys a very special message. It means the side suit is not going to produce as many tricks as the declarer may have hoped. (If the side suit had been breaking well, the defender would have made a more active lead.)
Thus, if you are playing at 4♠ after having bid hearts, an original trump lead will usually mean the player who has led it has the heart suit well in hand. Somewhat less reliable is the deduction that arises if you play at 4♠ after dummy has opened 1 and rebid 2. A trump lead in this case may mean the player on your left is short on diamonds and expects the suit to be well stopped by his partner.
Here is a typical case where a sleuth-like declarer may profit from a deduction based on an opening trump lead:

♠ K 7 5 2
Q J 7 6
A 9
♣ 5 4 3
♠ A 10 6 4
K 8 2
J 7
♣ A K J 8
South North
1♣ 1
1♠ 2♠
3♠ 4♠

The &spades2 is led and East plays the queen, which you win with the ace. You draw a second round of trump with the king. West playing the nine and East the three. What now?

For a start, you should assume for the moment that the club finesse is going to lose, for otherwise the contract would be icy. You must therefore plan to establish a long card immediately in either hearts or clubs, aiming to discard a diamond on it and so limit your losses to three tricks.

Of course, you anticipate that unless the defenders are chumps, they will shift to a diamond as soon as they gain the lead in hearts or clubs. Therefore, it is important to gauge which of these suits is more likely to break 3-3. You will not have time to try them both.

West’s lead of a trump affords the best indication. It suggests that he does not expect you to set up many tricks in your first-bid suit, clubs. He may well hold something like Q-10-x-x. You should therefore go after the hearts, driving out the ace and planning to discard your diamond loser if the suit breaks 3-3. Even if the hearts divide unfavorabley, you can still fall back on the club finesse for your contract.

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