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a question of hypothesis

#1 User is offline   cencio 

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Posted 2018-November-28, 03:45

Let's say that to make a hand one must necessarily finesse in a suit, but if the finesse goes wrong, he loses more tricks than if he had taken another path.
How to behave: always look for the contract?
in practice are there hands where to settle for a less poor result rather than risk?
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#2 User is offline   helene_t 

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Posted 2018-November-28, 04:29

Most often, it is right to try to make the contract. At IMPs this is almost always the case, unless you have clues from the bidding and play that the finesse is very unlikely to work. Even then, you should probably still take it if you are nonvulnerable and not doubled, as the extra downtrick is cheap.

At matchpoints, there are more exceptions. If you were lucky to be allowed to play a cheap sacrifice, or if the defense has already screwed up and missed a chance to take several downtricks, you may judge that one down will be a good score so it is not worth the risk to try to make.
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#3 User is online   mikeh 

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Posted 2018-November-28, 13:15

To expand on the good advice from Helene:

Always ask yourself this:

How do I expect to score if I settle for -1? How to I expect to score if I take the finesse? Both if it wins and if it loses.

Assuming no clue from the play or auction as to the odds of the finesse winning, take the finesse if you think that the gain from it winning is bigger than the gain from it losing. Not by comparing, say, +140 to -100 or -200, but in terms of what kind of matchpoint score the different results might generate, or the imp swings.

This often means that you have to have some impression of how 'normal' your contract is.

For example, assume that you or your partner did something a little off the wall, and you have reached a 4S contract that very few would ever reach. Miraculously you see that you have a 50-50 play for the contract, but you will go down 200 if it loses, while you can cash out for -100.

Well, if you think the field will likely be taking a small plus your way, by staying at a lower level or by defending, then you are getting a bad score for any minus. Maybe not a zero for -100, but a bad score.

Let's say that you estimate that -100 will get you at most 25% of the matchpoints, but that -200 will get you zero.

Taking the finesse will cost you 25% of the board if it loses.

But what if it wins? Given the conditions, you can probably estimate a 90% or better result if you make. So the finesse stands to gain you 70% of a board, while risking 25% of the board. You'd need to be almost certain that the finesse will lose before you refuse to take it.

Another example: you reach 3N and realize that your 4-4 or 4-5 major suit would score 620 and you can cash out for 600 or try for 630, while risking a minus. It is probably fair to assume that much of the field is in the major, so settling for 9 tricks is almost surely a bad result at mps...take the finesse.

At imps, tho, it would be crazy to take the finesse: scoring 600 loses 1 imp. Scoring -100 loses 12!

A different scenario: you have sacrificed, and think that many pairs will let them play their cold vulnerable game.

You can cash out for -500 or finesse and risk -800 and hope for -200. So long as a significant percentage of the field lets them play their game, you should cash out. There will be relatively little mp difference between -200 and -500, but an enormous difference between -500 and -800.

At imps, however, getting out for -200 means winning 10 imps if your teammates are in game, making, while going -800 costs only 5 imps! So if unless the finesse seems very likely to lose, take it.

There are, of course, many other situations to consider. For example, sometimes you don't know if the opps' contract would make...it may even depend on whether the finesse wins or loses...if it wins, they would go minus, while if it loses, they make their contract.

So there is no one size fits all answer. What I can say is that at mps, particularly in partscore battle hands, it usually (but not always) pays to risk the extra undertrick for the contract if the decision is close. You are unlikely to be a winning matchpoint player if you consistently settle for small minus scores. Too many things can go wrong at other tables to allow you to conclude that playing for -100 is a good idea. At other tables, your side may be playing at a lower level, or there may be misdefence, and so on. If you have the balance of power on a hand, it is best to play for a plus score unless you have very good reason to think that the finesse will lose.
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#4 User is online   Winstonm 

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Posted 2018-November-28, 16:45

In my experience where this has occurred has more often been in Moysian fits - playing for the 3-3 leads to down several if the 3-3 doesn't occur while catering to the more likely 4-2 settles for down 1. Do you play for +110, -100, or -300/400?
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#5 User is offline   mikestar13 

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Posted 2018-November-29, 07:57

View PostWinstonm, on 2018-November-28, 16:45, said:

In my experience where this has occurred has more often been in Moysian fits - playing for the 3-3 leads to down several if the 3-3 doesn't occur while catering to the more likely 4-2 settles for down 1. Do you play for +110, -100, or -300/400?


Multiply the mp/imp expectation of +110 by the chance of a 3-3 split, multiply the expectation for -400 by the chance of a 4-2 or worse split, and add the numbers together. Now compare that to the expectation for -100. More likely right to play safe than on a finesse, but it still may be right to go for it, depending on the odds.
If the odds make it too close to call on any decision, I aim to go plus rather than minus,to get the biggest plus if there are no minuses, and to get the smallest minus if there are no pluses. But the odds make the correct action clear most of the time.
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#6 User is offline   mikestar13 

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Posted 2018-November-29, 08:03

Toward the end of a match, state of the match considerations also are involved. In teams, if you have a comfortable lead, tend to play safe, if badly behind go for it, if about even follow the odds.
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