At times when playing against a fine dummy player of Bridge, one wonders at how he comes to know more often than not the right line of play, sometimes dropping singleton kings, at times placing the key cards in the right spot to win the 2 way finesse. Let us first illustrate by an example where NS quickly reached a 4S contract on the following bidding and hand. West opened the lead with a club 10 and the east took the first 2 club tricks with KA shifting to a diamond.
Declarer after winning the diamond shift played the QS and when west played low, went up with the ace confidently. But west has held the following hands:
The question posed by west was why he did not finesse for the KS. South's answer reflected the crux of the issue at hand for NS held:
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North
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A 6 4
K 8 7 6 5 3
8 3
Q 5
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South
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Q J 10 9 8 7
4 2
A K Q
8 2
============
South explained that if west held the KS, the finesse if taken would only yield 9 tricks for then surely the KH would never score as east who had called was surely holding the AH so the only chance for the declarer to succeed in 4S was to assume west has the AH and east the KS and that too a singleton.
Let us take another illustration to highlight this force of assumption of cards north south reach 4S on the following hand:
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North
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K 10 9 6
J 5 4
K 8 5 4
7 6
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South
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A Q J 7 4
9 3 2
J 9
K J 10
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The bidding:
West leads the KH followed by the QH and the 10H to east's ace. East returns a small club.
Suppose NS had held this hand:
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North
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K Q 10 9
J 5 4
J 4 3 2
7 6
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South
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A J 7 6 4
9 3 2
Q
K J 10 3
=========
In both cases, on the return of a small club after 3 heart tricks are cashed, as south what is your play in each hand and why? In the first case, the placement of the DK is important. By card place assumption for your contract to succeed you must assume west has the AD for your KD to win. Once you assume AD with west who has already shown KQ of hearts and yet passed in the opening seat, you can rightly assume that west cannot have the club ace. So you go up with the KC and succeed when west east produce:
In the other case, south's only concern being the club suit,west who has shown up with KQ of hearts and not shifted to a diamond, places the diamond top honours to be split, so had west the club ace, he would surely have opened. Hence the correct play again is to go up with the club king for west east held:
So the principle of card to card location is to be followed by assuming it to be where one can succeed. Like in the following NS hand:
West opened ID, east responded is south 2C and east 2D; north to bid 3C as final bid, west cashes KA of diamonds and plays 10S. South's losers are 2 diamonds, one heart for sure. There can be further losers in hearts and spades. But as south you must assume AH to be with east for your 3C to succeed. Otherwise 2 heart losers will sink your 3C contract. On this assumption west surely has spade ace to open the bidding therefore the correct play is to go up with KS on the principle of CPA - card placing assumption.
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E S W N
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1C 1S P 2H
P 2S P 4S
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All Pass
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West East
K 5 2 3
Q 10 9 A J
9 6 5 4 J 10 7 2
10 9 7 A K J 6 4 3
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W N E S
P P P 1S
P 2S All Pass
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West East
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8 5 3 2
K Q 10 A 8 7
A 7 6 2 Q 10 3
Q 5 4 2 A 9 8 3
====================
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West East
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8 5 3 2
K Q 10 A 8 7 6
A 9 6 5 K 10 8 7
Q 8 5 4 A 9 5
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North South
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K J 5 4 7 3
8 7 2 K Q 5
8 6 3 Q 9
K J 8 A Q 10 9 7
=====================