[barmar]

Found an example in Sheinwold's 60-year-old "Duplicate Bridge":

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The opening lead is ♣2 to the Ace, and East returns ♣4. Sheinwold says that since the field will be in 4♥, you have to assume that this makes only 10 tricks (i.e. diamonds are 3-1), and you should take the spade finesse to make 10 tricks in NT to catch up.

For some reason he says that South should prepare some "choice remarks" for his partner for leaving him in this contract. I admit that I have only vague memories of NT bidding before I learned transfers, but didn't 3♥ show 5 of them, so South should have bid 4♥ rather than 3NT?

[CSGibson]

barmar, on 2014-January-17, 15:58, said:

Found an example in Sheinwold's 60-year-old "Duplicate Bridge":

---

The opening lead is ♣2 to the Ace, and East returns ♣4. Sheinwold says that since the field will be in 4♥, you have to assume that this makes only 10 tricks (i.e. diamonds are 3-1), and you should take the spade finesse to make 10 tricks in NT to catch up.

For some reason he says that South should prepare some "choice remarks" for his partner for leaving him in this contract. I admit that I have only vague memories of NT bidding before I learned transfers, but didn't 3♥ show 5 of them, so South should have bid 4♥ rather than 3NT?

So the common theme in these examples is that by altering your line of play, you actually have some chance to outscore the majority who are in the correct contract. Do you see how that is different than examples where you are in game and the field is in slam?

[GreenMan]

CSGibson, on 2014-January-17, 16:16, said:

So the common theme in these examples is that by altering your line of play, you actually have some chance to outscore the majority who are in the correct contract. Do you see how that is different than examples where you are in game and the field is in slam?

Only in the details. barmar's hand requires us to envision a distribution that limits the tricks available in the correct contract, and to take a line that has a higher expected score value only if that distribution exists. Seems the same to me.

[GreenMan]

ArtK78, on 2014-January-17, 15:10, said:

FYP. They may have diamonds to cash if they led a diamond and you lose the club finesse.

Yeah, didn't think of the concise way to express it that you did, and figured it was obvious enough not to need my clumsier version.

[CSGibson]

GreenMan, on 2014-January-17, 17:36, said:

Only in the details. barmar's hand requires us to envision a distribution that limits the tricks available in the correct contract, and to take a line that has a higher expected score value only if that distribution exists. Seems the same to me.

Its not the same. Its close, but there are significant differences. Your matchpoint score relative to the field in slam is not going to change based on you taking more tricks via an alternate line of play - you get a top if they go down, and a bottom if they don't, irrespective if you took 11 or 12 tricks. The only thing you have to worry about at the table is taking the same line as everyone else so that you take the same amount of tricks (hopefully 11, but 10, 9, or even less works just as well as long as you are a level lower, thus getting the better score).

In the 2nd example, you are taking a different line of play because the ONLY way you are catching the field is to take the same amount of tricks, and you can see that it requires you to do something different than the field will do in their 4M contract. Now you alter your play, because how you play matters.


To put it in a different way, its risk reward. If you are one of 20% not in slam, then 80% of the board is already decided, you are now just competing for the remaining 20%. Taking a normal line gives you a positive EV in terms of the 20%, and has no relation to the 80%.

In the 2nd example, you have a chance to outpoint the people in the normal contract only by doing something abnormal. So say the same 80% are in 4M and 20% in your 3N. You are risking 10% of a board to have a chance of getting 90% in that circumstance, so your ev for an abnormal line is +EV as long as the abnormal line is better than ~10% - clearly dropping the doubleton Q, or taking a finesse beats that threshold.

I feel like I'm saying this poorly. Help?

[Vampyr]

CSGibson, on 2014-January-17, 17:48, said:

Its not the same. Its close, but there are significant differences. Your matchpoint score relative to the field in slam is not going to change based on you taking more tricks via an alternate line of play - you get a top if they go down, and a bottom if they don't, irrespective if you took 11 or 12 tricks. The only thing you have to worry about at the table is taking the same line as everyone else so that you take the same amount of tricks (hopefully 11, but 10, 9, or even less works just as well as long as you are a level lower, thus getting the better score).

Quite. You don't want to risk getting the same -50 that the people in slam scored, so actually it is usually best to play to try to make 12 tricks, because that is what the people in slam will be doing. If you are in luck they will not be successful.