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Match Point strategy decision

#1 User is offline   TheoKole 

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Posted 2019-May-14, 16:44




So you manage to get to a 6 contract after south opens a strong NT and you get a trump lead; trumps are 3-1. In the play you can take the chance of 1 of 2 finesses in the minors working about 75% with a 25% chance of going down and a 25% chance of getting +1. Of course there is a stronger play to make the contract by eliminating and and playing Ace and King .

If doubleton Q doesn't drop then give up the diamond and west is endplayed if the finesse was working originally and east is endplayed if they hold either the 10 or Q and the original finesse wasn't working. All together approx. a 90% chance of making the contract with a very small chance ~ 2% singleton or doubleton Q of having a chance for an overtrick.


So playing MP's which is the best percentage play for a top and which would you choose in the field. Do you think this one of the rare instances that it is correct theory- wise to play "safely" for the endplay?

I have not discussed playing against anyone in 6NT because you cannot practically play against anyone who bids 6NT for the board. Their most likely play on a heart lead is to try the 2 finesses which will either work or not. In either case they will score higher than you making 6NT or 6NT+1 or going down on the board when you would also have gone down.


Thanks in advance for the replies,


T
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#2 User is offline   Stephen Tu 

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Posted 2019-May-14, 19:45

If you were playing solely against people in 6H, I think you better take two finesses, of course taking top honor first.

(Following odds are a bit off since you didn't specify which opp had longer trumps)
Playing diamonds off the top wins when RHO has doubleton Q offside and (CQ onside (2.52%) or CQT offside (.71%)), and when RHO has 3-5 diamonds with the Q (~42%), along with the CT but not the CQ (endplay didn't help if Q onside or QT offside). So that's what, a bit less than 14% wins over finessing?
(If LHO shows out on the 1st diamond, there is an automatic endplay playing 3rds of clubs; if shows out on 2nd diamond I think usually better to play 3 rounds of clubs playing LHO for CQ for endplay rather than play third diamond).

OTOH, finessing twice wins whenever LHO has 3-6 with the Q (~44.9%) and RHO has the CQ (probably a bit more than half of that). 23%?? So some 9+% for just taking two finesses?

But if lots of field in 6nt then that tilts towards endplay since then you can beat them if you need an endplay.
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#3 User is offline   FelicityR 

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Posted 2019-May-15, 03:42

I'm only advanced not an expert, and I am not a great fan of MPs as it's a completely different game to IMPs - where making the contract matters, not so much the overtricks - but playing MPs I have always believed that making a contract is your first priority, and if you can steal an overtrick or two in the subsequent play that's a small bonus. Without doubt many good players will be in 6NT with these cards looking for a top, so you're already looking at a smaller MP score being in 6 hearts. As both the minor suits are 3-3 with finesse-able options, playing off the AK in either suit, after drawing trumps and eliminating the spades is a lower percentage play.

As Mr Tu says, taking both finesses after taking a top honour in both the minors is, in my opinion too, the best play. Trying to analyse how other partnerships are bidding and playing these cards is purely speculative.
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#4 User is offline   Tramticket 

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Posted 2019-May-15, 05:29

View PostStephen Tu, on 2019-May-14, 19:45, said:

But if lots of field in 6nt then that tilts towards endplay since then you can beat them if you need an endplay.


Estimating the field matters here. You would expect that with 33 HCPs everyone should reach a slam and some percentage (25%?) might opt for 6NT as match points.

But if the field is mixed and includes some weaker players, then maybe some are not in slam at all. Some may have pushed to seven (super-accept the transfer and north maybe gets over-excited?). This might tilt us to the safety play.

But the trump lead against 6 is intriguing and is a little unusual. It wouldn't surprise to find that west holds all three missing queens. I think that the chance of the diamond finesse working is rather more than 50%.
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#5 User is offline   Stephen Tu 

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Posted 2019-May-15, 06:17

View PostTramticket, on 2019-May-15, 05:29, said:

But if the field is mixed and includes some weaker players, then maybe some are not in slam at all.
You'd need absolute beginners. 18 opposite 15 isn't a hand where I am considering people not in slam. It's the percentage in 6nt that matters.

Quote

Some may have pushed to seven (super-accept the transfer and north maybe gets over-excited?). This might tilt us to the safety play.
People in 7 are immaterial. They either beat you already (both finesses on), or you beat them regardless (by making 6, or by being only down 1 instead of down 2).

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#6 User is offline   rhm 

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Posted 2019-May-15, 06:24

View PostFelicityR, on 2019-May-15, 03:42, said:

I'm only advanced not an expert, and I am not a great fan of MPs as it's a completely different game to IMPs

True, but I find the reasoning hollow. IMPs is also quite different to Total Points. Does this mean we should all be fans of Total Points and reject IMPs?
The strategy of MP is as intriguing as that of IMPs and I see no good reason why one should be preferred over the other.

View PostTramticket, on 2019-May-15, 05:29, said:

But the trump lead against 6 is intriguing and is a little unusual. It wouldn't surprise to find that west holds all three missing queens. I think that the chance of the diamond finesse working is rather more than 50%.

Maybe, but if West holds all missing queens what do you gain by taking the diamond finesse? If the diamond finesse is better on the lead, the chance that the club queen finesse is working has diminished by the same argument.

Rainer Herrmann
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#7 User is offline   msjennifer 

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Posted 2019-May-15, 21:15

Sirs,if playing in an average standard field I have to keep level with the field if its a MP event,Safety plays are next in order.Practically everyone who does not understand the importance of spot cards are going to take to take both the finesses and score all 13 if the finesses are working.In that case a safety play will make the contract MOST of the times but one gets almost a certain ZERO in such a field.In a better than average field I shall certainly make the safety play losing only to those who bid and make a grand slam.IN any IMP event I shall always take the safety play hoping to lose only one IMP to opponents taking both winning finesses and of course a bushel to opponents if they bid and make the grand,
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#8 User is online   helene_t 

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Posted 2019-May-15, 22:28

Unless I am playing in an extremely weak field where most would just be in game (or part-score), I would go for 13 tricks.

Against those who are in 7, it is good enough. Even if you are 1 down, they will probably be 2 down so you still beat them.

Against those who are in 6NT, you have to make an overtrick and hope they play safe.
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#9 User is offline   Stephen Tu 

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Posted 2019-May-16, 02:20

View Posthelene_t, on 2019-May-15, 22:28, said:

Against those who are in 6NT, you have to make an overtrick and hope they play safe.

How's that going to work? You only make overtrick if both finesse work. 6nt is going to take first finesse, it will work. No reason for them not to take the other at this point. It's not like they have 1 spade stop which was knocked out on opening lead.

If think substantial portion of field is in 6nt, I think you have to go for endplay and hope it necessary to make the contract. (Or find the doubleton DQ offside which will help your cause also).
If think 6nt not so common, then try make 7.

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#10 User is offline   rmnka447 

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Posted 2019-May-16, 12:00

View PostStephen Tu, on 2019-May-16, 02:20, said:

How's that going to work? You only make overtrick if both finesse work. 6nt is going to take first finesse, it will work. No reason for them not to take the other at this point. It's not like they have 1 spade stop which was knocked out on opening lead.

If think substantial portion of field is in 6nt, I think you have to go for endplay and hope it necessary to make the contract. (Or find the doubleton DQ offside which will help your cause also).
If think 6nt not so common, then try make 7.

I think you're exactly right.

Now that the final contract is 6 , you'll only get a really good score when 6 makes but 6 NT doesn't. So keep faith with the bidding and make the best play you can to make 6 .
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#11 User is offline   gszes 

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Posted 2019-May-16, 13:48

I am in a strong contract that that will only be beaten by 6n (maybe a bit over 80%) making or the 7 level making (28% or so). IMHO I would try to take advantage of the fact that I am playing in hearts and go for the strip and endplay.
trick 1 win heart lead
trick 2 heart
trick 3 heart
trick 4 spade A
trick 5 spade K
trick 6 ruff spade
trick 7 dia ace
trick 8 dia K assuming the Q has not fallen
trick 9 exit a dia
if west wins the trick the hand is over (lead a club or give ruff/sluff
if east wins the trick they must exit a club (or give ruff/sluff and we play low and now lho must hold both the Q AND the T of clubs for us to go down

this LOP is around 90%
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#12 User is offline   TheoKole 

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Posted 2019-May-16, 19:58

View PostStephen Tu, on 2019-May-15, 06:17, said:

You'd need absolute beginners. 18 opposite 15 isn't a hand where I am considering people not in slam. It's the percentage in 6nt that matters.

People in 7 are immaterial. They either beat you already (both finesses on), or you beat them regardless (by making 6, or by being only down 1 instead of down 2).


By the same reasoning, aren't the people in 6NT immaterial? They either beat you or you beat them. They beat you by 10 points, except in the case of doubleton Q with east (which they would not play for) or in the case where the minor suit Q's are offside and east has the 10 clubs incase they go down and you make your contract.


Regards, T
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#13 User is online   nige1 

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Posted 2019-May-16, 20:17


Thank you for the intriguing problem, Theokole.
Stephen Tu's conclusions seem correct
Although they confirm Justin Lall's advice, about eschewing safety-plays at match-points, I still found them surprising.
If the field is in 6, it appears that you should take 2 finesses.
If you suspect that several pairs will reach 6N, however, then you should eliminate and play AK and another.
IMO, in real-life, a wheel sometimes comes off, leaving a few players in game, in which case, you should again consider the safety-play.

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#14 User is offline   Stephen Tu 

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Posted 2019-May-16, 20:48

View PostTheoKole, on 2019-May-16, 19:58, said:

By the same reasoning, aren't the people in 6NT immaterial? They either beat you or you beat them. They beat you by 10 points, except in the case of doubleton Q with east (which they would not play for) or in the case where the minor suit Q's are offside and east has the 10 clubs incase they go down and you make your contract.


No.
Suppose you knew that everyone else was in 6H. I think I demonstrated fairly clearly that two finesses wins more MP in the long run (endplay makes 6 vs down 1 close to 13% more often, but gives up the overtrick for making 6 instead of 7 close to 23%).

Suppose you knew everyone else was in 6nt. If you take two finesses, *6nt nearly always beats you*, unless both finesses are off and you tie for down 1. The only cases you win are when RHO has doubleton Q and is endplayed (about 1.08%), and when LHO shows out on the first diamond and has CQ (~0.18%), and when LHO has 1 diamond and you throw him in with CQ (1.83%). So against 6nt, playing two finesses (but abandoning when LHO shows out on diamonds) gets a top about 3.09% of the time, ties about 23%, and gets a bottom the rest. Expectation is about 14.6% of the available MP.
OTOH if you go for the endplay, now you win when DQ is doubleton offside (4.36%), when LHO has short diamonds as above (2.01 again), and when RHO has DQ with 3-5 diamonds and CT but not CQ (~10.98%). Now you get a top 17.35% of the time, and still tie about 14.94% of the time. Expectation is now 24.82%. Clearly it's better to hope the endplay is necessary as it allows you to overtake the 6nt players.

There is some point where it's a tossup depending on the relative split of opps in 6h vs opps in 6nt, I haven't gone through the trouble to calculate exactly where it is.
6nt is not immaterial because they can't play for an endplay. An endplay allows you to overtake them when it is necessary, you will make while they go down 1. People in 7h can't play for an endplay either, but in this case finessing beats them whenever 7 doesn't make because you are a level lower, and you can still beat them by being down 1 instead of down 2. Tie in tricks that isn't 13 is a win. But for the 6nt bidders, you need to take more tricks than them to win.

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#15 User is offline   TheoKole 

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Posted 2019-May-16, 22:04

View PostStephen Tu, on 2019-May-16, 20:48, said:

No.
Suppose you knew that everyone else was in 6H. I think I demonstrated fairly clearly that two finesses wins more MP in the long run (endplay makes 6 vs down 1 close to 13% more often, but gives up the overtrick for making 6 instead of 7 close to 23%).

Suppose you knew everyone else was in 6nt. If you take two finesses, *6nt nearly always beats you*, unless both finesses are off and you tie for down 1. The only cases you win are when RHO has doubleton Q and is endplayed (about 1.08%), and when LHO shows out on the first diamond and has CQ (~0.18%), and when LHO has 1 diamond and you throw him in with CQ (1.83%). So against 6nt, playing two finesses (but abandoning when LHO shows out on diamonds) gets a top about 3.09% of the time, ties about 23%, and gets a bottom the rest. Expectation is about 14.6% of the available MP.
OTOH if you go for the endplay, now you win when DQ is doubleton offside (4.36%), when LHO has short diamonds as above (2.01 again), and when RHO has DQ with 3-5 diamonds and CT but not CQ (~10.98%). Now you get a top 17.35% of the time, and still tie about 14.94% of the time. Expectation is now 24.82%. Clearly it's better to hope the endplay is necessary as it allows you to overtake the 6nt players.

There is some point where it's a tossup depending on the relative split of opps in 6h vs opps in 6nt, I haven't gone through the trouble to calculate exactly where it is.
6nt is not immaterial because they can't play for an endplay. An endplay allows you to overtake them when it is necessary, you will make while they go down 1. People in 7h can't play for an endplay either, but in this case finessing beats them whenever 7 doesn't make because you are a level lower, and you can still beat them by being down 1 instead of down 2. Tie in tricks that isn't 13 is a win. But for the 6nt bidders, you need to take more tricks than them to win.



Thank you for your careful analysis of the hand and the thinking. I had this problem playing MP's at our local club game and was unsure whether my final decision was theoretically correct or not. I think that it seems a tossup as to whether most other pairs will be in 6NT or 6 on the hand. Having only up a minute to go though the thinking on such a hand is difficult so I find it beneficial to think about these types of hands for future reference when I will be playing similar types which will require similar decision making.


Regards, T
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#16 User is offline   WesleyC 

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Posted 2019-June-14, 12:03

I think the most important MP idea on these hands is that both North and South need to keep 6NT in the picture during the auction.

In even an advanced field, playing 6H on these cards is a MP disaster!
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