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Choice of contracts How do you best evaluate your chances

#1 User is online   thepossum 

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Posted 2019-August-02, 15:53

Hi,

Recently playing IMPs I had what seemed to be (and was) a perfectly fitting hand with 5-3 in both majors and 3-2 in both minors. How do you proceed and evaluate options after the following start. Would it be different at MPs



This was my auction but I wanted to explore more after 1NT and was a bit unsure of all the bids available to find best choice of major or NT. For example the spades are stronger than hearts. Please ignore EW hands
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#2 User is online   Cyberyeti 

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Posted 2019-August-02, 16:51

Clearly looking at both hands, 3N is the best contract, but I suspect nobody is going to play there, 4 comes next then 4, all should make on the actual lie of the cards.

Depends on agreements how you bid this.

1-1-1N-2m(checkback, or GF checkback if you play that)-2-4 I would have thought should say I want to play 4 of one of your majors, bid the one with the most stuffing in it unless you play it as a splinter in pd's suit slamgoing.
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#3 User is online   smerriman 

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Posted 2019-August-02, 18:24

Cyberyeti's suggestion sounds like a good one. Unfortunately, GIB describes 4 as only 4+ spades, and won't correct you to 4 with this hand. So with GIB, there's no point revealing your double fit; your auction sounds fine.
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#4 User is online   Tramticket 

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Posted 2019-August-03, 14:02

Did East really lead the King of hearts?!!!
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#5 User is online   thepossum 

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Posted 2019-August-03, 15:01

View PostTramticket, on 2019-August-03, 14:02, said:

Did East really lead the King of hearts?!!!


Yes :)

I'm getting used to the leads by now and it usually shows a bad break

Just thinking about it though. Its not a bad lead on the hands and given the auction. The auction suggested that trumps could be a good lead and it potentially denied a ruff and promoted a trump control for West? Maybe someone can comment. Trump leading is not my strength. I know its recommended if you are trying to deny a ruff and think their may be difficuties making the contract. Is it not a good lead. Its quite an attacking lead yes?? Maybe it was the least worst lead. Double dummy gives no difference in any leads - I just checked. I know it takes away a possible lost trick on a finesse but surely it has some merits. Hopefully someone can explain

PS I just ran a quick sim and there isnt much chance of setting the contract. Ace diamonds (then clubs) came up as best lead (in terms of average tricks) but there isnt much difference between the rest. What do all the experts say?
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#6 User is online   smerriman 

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Posted 2019-August-03, 18:58

GIB leads the king because it assumes that declarer will know it is a singleton and drop it under the Ace; therefore it will never take a trick. This of course is silly in reality, but it's just how the robots work.

Adjust your sim to assume a 'normal' line of trump play and you'll probably discover that the king costs you the contract many times that double dummy says it makes no difference.
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#7 User is online   thepossum 

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Posted 2019-August-03, 19:15

View Postsmerriman, on 2019-August-03, 18:58, said:

GIB leads the king because it assumes that declarer will know it is a singleton and drop it under the Ace; therefore it will never take a trick. This of course is silly in reality, but it's just how the robots work.

Adjust your sim to assume a 'normal' line of trump play and you'll probably discover that the king costs you the contract many times that double dummy says it makes no difference.


I did say it wasnt the top lead :)

Ace diamonds first
Clubs next
Then the rest fairly equal with not much chance of any setting the contract.
But it was a 5 minute back of the envelope sim. I'm not in the sim business and dont pretend to be :)

All I said was that it is seems to be the way the bot plays with an uneven trump break to try to give trump control to partner. I have noticed it before

Note. Here are the chances of making 4+ tricks (almost 0). I just reran it and it given there is so little difference it has a slightly different order :) The above results were relating to average tricks, not setting the contract :)

Spade 0.056
Club 0.054
Ace D 0.05
KH 0.044
Small D 0.043

95% CI Approx +-0.012

Edit For completeness this is the lead order to maximise expected number of tricks

Average number of tricks maximised by leading Ace D
Ace D 1.91 tricks
Small C 1.69 tricks
QC 1.66 tricks
Spade 1.65 tricks
K H 1.59 tricks
Small D 1.58 tricks

95%CI Approx +- 0.07


But as I said it was a 5 minute (3 to write and 2 to run) basic script and 1000 deals using bdeal. Nothing fancy in the script at all. Just a few constraints and double dummy :) I don't spend much time looking at sims although simulating leads is fun to compare with expert theory. I don't have much time left to explore that. I'm more interested in the statistical theory and game theory of competitive bridge - but I hasten to add I am a disinterested amateur, unafiliated to anyone other than myself and my (almost retired) business is not related to bridge in any way. This is a nice relaxing way for me to keep my mind active in the absence of (lack of motivation to chase any) serious contracts :)
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#8 User is offline   akwoo 

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Posted 2019-August-04, 00:21

The bots play regular new minor forcing. This means, after 1H-1S-1N, a bid of 2C is artificial and forcing, and asks partner to bid 2S with 3 spades. That was probably the right bid here.
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#9 User is offline   etha 

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Posted 2019-August-04, 02:33

Is the general rule for these sort of hands you want to be in the better trump fit? I had a vague recollection that the worse fit was better for some reason with the side suit already set up ?
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#10 User is online   Cyberyeti 

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Posted 2019-August-04, 02:54

View Postetha, on 2019-August-04, 02:33, said:

Is the general rule for these sort of hands you want to be in the better trump fit? I had a vague recollection that the worse fit was better for some reason with the side suit already set up ?


Depends if you have the side tricks to dispose of one or more of the losers in the worse suit playing in the better.
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#11 User is offline   bravejason 

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Posted 2019-August-06, 05:40

View Postetha, on 2019-August-04, 02:33, said:

Is the general rule for these sort of hands you want to be in the better trump fit? I had a vague recollection that the worse fit was better for some reason with the side suit already set up ?


I once read a comment to the effect of ‘you can’t discard trump losers’, suggesting that it is better to have the stronger suit as trump.

It seems to me that one should prefer the weaker suit as trumps on the basis that weak trump cards can still win tricks via ruffing whereas weak side suit cards always lose. That said, I’ve seen hands where I wished one was the other and vice versa. So, the best thing I’ve found to do is not worry about it and just let the cards fall where they may.

It’d be better, of course, to figure out during the bidding which suit should be trump and which should be the side suit and bid accordingly, but I’ve no idea how one would go about doing that considering that the exactly which cards held by partner are unknown and the exact number of cards held is often unknown too.
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