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Finesse or Drop? ACBL

#21 User is offline   Lovera 

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Posted 2017-September-13, 08:02

If the situation is fifty-fifty (lacking information about) and you need finesse, can be applied the "Paul Lucacks" gadget as i indicated here: http://www.bridgebas...post__p__790905
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#22 User is offline   Kapi Blas 

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Posted 2017-September-13, 11:55

View Posthrothgar, on 2017-September-13, 05:10, said:

FWIW, with hands like this one I here's what I was taught:

On Trick 1 Lead the 10 of Hearts from hand.

If LHO doesn't cover or hitch raise with the King and then run the Jack back in the other direction...


Why would you ever play for lower percentage play instead of the better one? I can't imagine anyone covering this 10 with Q, ever. Opponents probably knows that you have 9-card suit and even if it would be 8-card there is no reason to raise with the Q because playing 10 from 10xxx to KJxx is therefore incorrect line of play. Playing for drop seems pretty obvious here.
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#23 User is offline   miamijd 

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Posted 2017-September-13, 14:32

The percentage analysis given above by a couple of folks is NOT correct at all. You can't simply add probabilities of non-mutually exclusive events.

In the absence of any information (which you may have - more below) -- and assuming that your opponents are good enough to play low in tempo with Qxx -- the drop is slightly better as explained below.

Let's say you have no clue as to how spades are divided (you know they are not 7-1 or 8-0, but let's say that's it). When you play the first round of hearts, everyone follows low, and when you play the second round of hearts, second hand plays a low card. That is the only situation that matters. The "Law of Vacant Places" says that it is now 12 to 11 (52.2%) to play for the drop. The player who has played one low heart has 12 vacant places; the other player has 11. It is therefore 12/11 that the player who has played only one low heart has the Q.

Since both players have played two spades, you might extend this to say the odds are now 10/9 (52.6%).

But you might have some other information. What are the opponents' leads? Did LHO lead the 3s and play the 2s at trick 2? If the opponents lead fourth best and don't play MUD from three, LHO either has 2 spades or 5 spades. You can probably tell which by noticing what card RHO returned. If you can determine who has 5 spades and who has 2 spades, you should play the opponent with short spades for the Qh.

Cheers,
mike
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#24 User is offline   hrothgar 

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Posted 2017-September-13, 15:18

View PostKapi Blas, on 2017-September-13, 11:55, said:

Why would you ever play for lower percentage play instead of the better one? I can't imagine anyone covering this 10 with Q, ever. Opponents probably knows that you have 9-card suit and even if it would be 8-card there is no reason to raise with the Q because playing 10 from 10xxx to KJxx is therefore incorrect line of play. Playing for drop seems pretty obvious here.


Because I am not playing in the BB or the finals of the Blue Ribbon Pairs and being able to watch people as they hitch is more valuable then playing the cards correctly
Alderaan delenda est
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#25 User is offline   miamijd 

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Posted 2017-September-13, 15:46

View Posthrothgar, on 2017-September-13, 15:18, said:

Because I am not playing in the BB or the finals of the Blue Ribbon Pairs and being able to watch people as they hitch is more valuable then playing the cards correctly


Any decent player is going to play low in tempo against a slam. GIB Bots will generally cover, but I wouldn't call them decent players,
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#26 User is online   sfi 

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Posted 2017-September-13, 16:00

View Postmiamijd, on 2017-September-13, 14:32, said:

The percentage analysis given above by a couple of folks is NOT correct at all. You can't simply add probabilities of non-mutually exclusive events.


You might want to be a bit more specific than that. Given that my analysis was about the only one that actually added probabilities, it sounds like you are disagreeing with what I wrote. I am interested to know where you think the errors lie.
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#27 User is online   sfi 

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Posted 2017-September-13, 16:02

View PostLovera, on 2017-September-13, 08:02, said:

If the situation is fifty-fifty (lacking information about) and you need finesse, can be applied the "Paul Lucacks" gadget as i indicated here: http://www.bridgebas...post__p__790905


This only works if you've chosen the card in question before finding out who has it. It is just a simplistic application of vacant spaces, similar to playing for queens to be split.
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#28 User is offline   Winstonm 

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Posted 2017-September-13, 16:13

First thing to consider is that with either a start with the ace or the king, half the time when the suit is 4-0 you will have guessed wrong. Once both opponents follow suit, 4-0 breaks no longer matter. Now it is simply a matter of whether or not to play for the remaining cards to be divided 1-1 or 2-0, and half the 2-0 breaks will be offside.

Of course, when the opp follows to the next card with a low one, half of the remaining 2-0 breaks are eliminated.
If something cannot go on forever, it will stop. - Herb Stein
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#29 User is offline   miamijd 

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Posted 2017-September-13, 19:49

View Postsfi, on 2017-September-13, 16:00, said:

You might want to be a bit more specific than that. Given that my analysis was about the only one that actually added probabilities, it sounds like you are disagreeing with what I wrote. I am interested to know where you think the errors lie.


You're right ex ante. But that means nothing, because the only situation you care about is one where you see three small cards on the first two rounds and have to guess whether trump are 3-1 or 2-2. The stiff Qs and the 4-0s can be eliminated. So saying it's 57 to 56 or some such thing is not correct after we have determined that trump are not 4-0 and there is no stiff Q. Now the percentages are different.

This is where the so-called Law of Vacant Places helps you.

Cheers,
Mike
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#30 User is online   sfi 

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Posted 2017-September-13, 20:02

View Postmiamijd, on 2017-September-13, 19:49, said:

You're right ex ante. But that means nothing, because the only situation you care about is one where you see three small cards on the first two rounds and have to guess whether trump are 3-1 or 2-2. The stiff Qs and the 4-0s can be eliminated. So saying it's 57 to 56 or some such thing is not correct after we have determined that trump are not 4-0 and there is no stiff Q. Now the percentages are different.

This is where the so-called Law of Vacant Places helps you.

Cheers,
Mike


Which I also described in my original post, so I'm still not sure where you believe the error in it lies.
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#31 User is offline   Lovera 

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Posted 2017-September-14, 02:01

View Postsfi, on 2017-September-13, 16:02, said:

This only works if you've chosen the card in question before finding out who has it. It is just a simplistic application of vacant spaces, similar to playing for queens to be split.

Infact. If the choising card appear in a side you have to make impasse on the other side similarly when honors are divided (52% vs 48%).
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#32 User is offline   kenberg 

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Posted 2017-September-15, 12:09

View PostGrahamJson, on 2017-September-13, 06:58, said:

Terrence Reece wrote of a hand in which, playing against two little old ladies, he needed to find a queen in order to make a slam (grand I think). He had another suit of something like A10x in dummy opposite KQJ in hand. He led the J from hand and LHO hesitated for a little before playing small. He then led the J of the key suit from hand. This time LHO did not hesitate so he let it run, successfully.


I vaguely recall a Victor Mollo variant of this. One of the Managerie characters, probably Secretary Bird, brought charges against another, perhaps Charlie the Chimp. Lacking the hand, we can use this one..SB leads the T from his hand, CC briefly hitches and then plays low. SB has no doubt that CC would play low smoothly from Qx so he assumes that CC had a stiff spot and was being "cute" with the hesitation. He therefore goes up with the K and leads a spot back to the 9. losing to the Q. SB argued that CC was taking advantage of the fact that he, CC, was known to fake thinking on plays that required no thought and so this action of hitching when actually holding something of value was unethical.

I do not recall the outcome.
Ken
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#33 User is offline   dokoko 

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Posted 2017-September-16, 00:13

IMO winning is better than playing "correctly". Even if every decent player will play low smoothly I have to consider the odds that the present opp is a non-decent one.

That said I guess most of the technical arguments are correct.

However, should my partner criticize me for preferring a 56% to a 58% line, he might as well look for a new partner.
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