Stayman with 44M less than invite

[y66]

I am actually quite open to the idea that garbage stayman should be used more often than it is.

But the idea that this is proven with the simulation data you linked to is laughable.

 

I have played a 4-3 fit or two in my life. And I know that (especially when our combined hands are fairly weak) I would really LOVE to know whether trumps split 3-3 or whether they split worse.

I also know that defending a 4-3 fit isn't easy, but it's much easier when you know it's a 4-3 fit from the beginning.

 

I would be happy to make a bet that double dummy results for declarer significantly outperform single dummy results in this situation (low-level partial, defense knows from the beginning that it's a 4-3 fit - say the auction was 1N-2C-2D-2H-2S).

I also know that defense again an unrevealing auction (1NT all pass) is harder than on average.

 

Can you or anyone construct a bet about the size of the double dummy bias in the 2 situations you describe such that a panel of 3 objective forum posters could inspect a reasonable number of reasonable samples and judge if you won or not?

[bluecalm]

Well, if you construct this bet I can search for every hand in vugraph history where 4-3 major fit was played and compare real results to double dummy results :)

[rhm]

Well, if you construct this bet I can search for every hand in vugraph history where 4-3 major fit was played and compare real results to double dummy results :)

I offer a bet that the average number of tricks taken double dummy in 4-3 fits will be within 0.5 tricks of the average number of tricks taken single dummy over all 4-3 fits you can unearth.

If the number of 4-3 fit deals is really large (more than ten thousand) the difference will be less than 0.3 tricks.

 

Rainer Herrmann

[gnasher]

Well, if you construct this bet I can search for every hand in vugraph history where 4-3 major fit was played and compare real results to double dummy results :)

That's probably not a fair test, because many of those will be deals where the players chose to play in a 4-3 fit. Those will tend to be deals where the best line is more obvious.

[bluecalm]

That's probably not a fair test

 

I agree, can you think of better one ?

[Zelandakh]

I agree, can you think of better one ?

Could you search specifically for the auctions:-

1NT - 2♣; 2♦

1NT - 2♣; 2♥

1NT - 2♣; 2♠

1NT - 2♣; 2♦ - 2♥

1NT - 2♣; 2♦ - 2♥; 2♠

 

and pull up only those that result in 7 card fits? If so, how many hands does this provide? If not enough then perhaps we can also come up with some additional auctions that fill the bill to reach a reasonable sample size.

[gnasher]

Could you search specifically for the auctions:-

...

and pull up only those that result in 7 card fits?

Again, that's not a fair test, because the declaring side chose to follow a route that might lead to a 4-3 fit. Part of Cherdano's proposition was that it be an arbitrary 4-3 fit.

[gnasher]

I agree, can you think of better one ?

I'd be happy with y66's suggestion that "a panel of 3 objective forum posters could inspect a reasonable number of reasonable samples and judge if you won or not".

 

That reflects my personal view of what we're trying to achieve here. If someone can persuade me that a particular approach will more often lead to what I consider a better contract, I'll pay attention. If the best they can do is to show that a double-dummy solver would have done better, but to me the contracts look worse from a single-dummy perspective, I won't be very interested.

[rhm]

I'd be happy with y66's suggestion that "a panel of 3 objective forum posters could inspect a reasonable number of reasonable samples and judge if you won or not".

 

That reflects my personal view of what we're trying to achieve here. If someone can persuade me that a particular approach will more often lead to what I consider a better contract, I'll pay attention. If the best they can do is to show that a double-dummy solver would have done better, but to me the contracts look worse from a single-dummy perspective, I won't be very interested.

The only type of contract, where I know this might happen is with grand slams and even there the difference in practice is rather small. (Single dummy you should be more conservative when bidding a grand)

 

Apart from that show me a large number of random or pseudo random deals, filtered and selected by any Bridge criteria you like, where a double-dummy perspective will consistently favor a certain type of contract to be better than another one, where single-dummy you would come to the opposite conclusion.

 

I would be really interested, but I am pretty certain you are talking in mathematical terms about an empty set, of which you can claim anything you like without being proven wrong.

If you have a large sample the few double dummy oddities are all but irrelevant to the result.

 

Rainer Herrmann

[gnasher]

The only type of contract, where I know this might happen is with grand slams and even there the difference in practice is rather small. (Single dummy you should be more conservative when bidding a grand)

 

Apart from that show me a large number of random or pseudo random deals, filtered and selected by any Bridge criteria you like, where a double-dummy perspective will consistently favor a certain type of contract to be better than another one, where single-dummy you would come to the opposite conclusion.

 

I would be really interested, but I am pretty certain you are talking in mathematical terms about an empty set, of which you can claim anything you like without being proven wrong.

If you have a large sample the few double dummy oddities are all but irrelevant to the result.

Why should I show you anything? You've asserted that, for the particular category of deals we're discussing, double-dummy analysis acurately models single-dummy play. So far as I can see, you have provided neither evidence nor argument in support of this assertion. And now you want me to do the work of testing it?

[rhm]

Why should I show you anything? You've asserted that, for the particular category of deals we're discussing, double-dummy analysis acurately models single-dummy play. So far as I can see, you have provided neither evidence nor argument in support of this assertion. And now you want me to do the work of testing it?

Nobody ever claimed double-dummy analysis accurately models single-dummy play. In fact it does not. Bridge is not played double dummy and never will be. (Thanks heaven)

What has been shown is that the differences cancel out and the outcome measured between average number of tricks taken at the table and by double dummy is over a large sample very close.

 

This has been shown for actual table contract results with only slight variations depending on strain and level.

Single dummy declarers have a slight, but only a slight, advantage in low level contracts, in particular notrump, supporting the view that 1NT is hard to defend.

(An argument for not running away from 1NT)

Single dummy declarer are at a slight disadvantage at slam contracts, where the defense often has few options and can therefor defend often double dummy.

This is not the case for declarer, who must uncover and then choose between options.

These differences are easy to understand.

 

So far I have heard no convincing arguments why 4-3 fits might possibly be any different and if it were, why does it not show up markedly already when the analysis of the total sample (30 million plays) was broken down according to strain and level?

After all 4-3 fits are much more common at low-level major suit contracts than anywhere else.

If a single dummy declarer is really at a disadvantage when playing 4-3 fits, why does this not show up?

Maybe 4-3 fits are harder to play, maybe not. But if they are, I do not see that the defense against 4-3 fits is on average any easier.

After all the defense may not even know that declarer is in a 4-3 fit.

 

I consider this pretty good evidence for my view.

 

Rainer Herrmann

[gnasher]

So far I have heard no convincing arguments why 4-3 fits might possibly be any different and if it were, why does it not show up markedly already when the analysis of the total sample (30 million plays) was broken down according to strain and level?

After all 4-3 fits are much more common at low-level major suit contracts than anywhere else.

If a single dummy declarer is really at a disadvantage when playing 4-3 fits, why does this not show up?

Maybe 4-3 fits are harder to play, maybe not. But if they are, I do not see that the defense against 4-3 fits is on average any easier.

After all the defense may not even know that declarer is in a 4-3 fit.

Perhaps because declarer's disadvantage in 4-3 fit partscores is counterbalanced by declarer's advantage in some other category of partscore. Or perhaps you're right and there is no significant declarer's disadvantage in 4-3 fits. I don't know - I'm not arguing that you're wrong, just that we should be properly sceptical. It seems unduly credulous to assume that an average which applies to all hands also applies to any given subset of hands, especially if this assumption leads to a conclusion which most people would find surprising.

[aguahombre]

So, is there a chance Cherdano's bet from post #45 can be set up to mutual satisfaction? Or are the conditions too tough to agree upon?

[benlessard]

DD isnt super reliable but I think its more reliable than human judgement in most of the cases. I think what is important is really understanding where DD fail and the degre of correction we need to apply. It will be nice to have a complete and user friendly simulator.

 

1-In low level contract DD greatly favor defense for the leads.

2- Hand where trumps dont break DD favor declarer.

3- 2 way finesse

 

etc

 

Once these things are better understood DD will be a great tool IMO