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math or simulation for this

#21 User is offline   PhantomSac 

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Posted 2014-December-23, 16:55

@Fluffy, I think it's just better to have an agreement as to what opener is going to do with 3-3. I believe Fred and Brad play opener always corrects to 2S, so with 5 good hearts and 4 bad spades you would just transfer to hearts and take your chances. Most people do the opposite (so with 5 good spades and 4 weak hearts you transfer to spades and take your chances). I think this is better than opener always deciding in the moment what to do with 3-3, you get to the better fit more often if it is already pre-determined what opener does so that responder can adjust accordingly sometimes. Of course no matter what sometimes you will end in the wrong fit. Another thing is you don't want to be tanking on whether to pass or correct every time, it gives away to the defense that you are 3-3 which is very bad.
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#22 User is offline   Jinksy 

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Posted 2014-December-23, 17:56

I tried bidding several random BBO hands where 1N 2C / 2D 2H could be on 4-4 or 5-4 (or 5-5) in H/S, and at least opposite a weak NT, I found that it was a huge winner over requiring 5-4.

The goal was to free up 1N 2C / 2D 2S as inv with exactly 4Hs, 5Ss, but I ended up finding - again, emphasis opposite a weak NT - that it was a much bigger gain playing that the old way - 4Hs, 5Ss, weak takeout.

I want to try the latter one more time, possibly later tonight, but from the few dozen hands I bid, the results were overwhelmingly in favour of the 2H-could-be-4-4, and strongly in favour of the 2S-weak meanings (ironic, given that the former was supposed to be a sacrifice to enable something different for the latter). I'll report back if I do, but atm I feel pretty confident that the UK standard approach is a poor one (given that it's generally played with weak NT).
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#23 User is offline   PhilKing 

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Posted 2014-December-23, 18:09

View PostJinksy, on 2014-December-23, 17:56, said:

I tried bidding several random BBO hands where 1N 2C / 2D 2H could be on 4-4 or 5-4 (or 5-5) in H/S, and at least opposite a weak NT, I found that it was a huge winner over requiring 5-4.

The goal was to free up 1N 2C / 2D 2S as inv with exactly 4Hs, 5Ss, but I ended up finding - again, emphasis opposite a weak NT - that it was a much bigger gain playing that the old way - 4Hs, 5Ss, weak takeout.

I want to try this one more time, possibly later tonight, but from the few dozen hands I bid, the results were overwhelmingly in favour of the 2H meaning, and strongly in favour of the 2S meaning. I'll report back if I do, but atm I feel pretty confident that the UK standard approach is a poor one (given that it's generally played with weak NT).


A lot of UK players of my acquaintance play 2 then 2 as inv with 5 spades, regardless of the heart holding, but that is irrelevant to this thread.
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#24 User is offline   PhantomSac 

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Posted 2014-December-23, 18:33

View PostPhilKing, on 2014-December-23, 18:09, said:

A lot of UK players of my acquaintance play 2 then 2 as inv with 5 spades, regardless of the heart holding, but that is irrelevant to this thread.


Ya ditto
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#25 User is offline   Jinksy 

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Posted 2014-December-23, 20:51

Hadn't seen that before. I dunno if people will be interested, since this is all quite subjective, but I've just tried a number of hands (around 70 including redeals, at a rough guess) on BBO where opener had a balanced 12-14*, and responder had either 5S 4H 0-12 points or 5Ss 0-4H and 10-12 points.

I discarded all hands where it seemed to make no difference (ie you'd end up in the same contract in each system), which introduces a very slight bias in favour of Phil's method above, since rightsiding the contract toward the stronger hand (via the alternative of xferring then bidding 2N) looked worth very roughly 1/10th of a trick whenever it came up.

I don't know how to share the hands atm, but I'll save them all and, if anyone's interested, upload what look like the key hands. My analysis is fairly superficial crypto-DD, based on a combination of what GiB can make in the contracts I let it judge (I can't rewind and check it on other when I bid from a teaching table, which I find otherwise much easier) and about 60 secs per board of looking at the outcome of the best DD play I could find. That said, if I saw an obvious example of DD play making a significant difference for one contract and not the other, I'd note it.

Testing the three meanings for 1N 2C / 2D 2S - a) 'any invite with 5Ss and 0-4Hs', b) 'invite with 5Ss and 4Hs', and c) 'weak takeout with 5Ss and 4Hs' - I'll skim through the hands again now and try and give a rough account. I'm assuming if playing a) or b), c-type hands bid Stayman then 2H unless the S suit was significantly better. This let's you find more 4-4s at the expense of playing in more Moyesians when there's a 5-2 (and, rarely, a 5-3) available, which seems like a decent tradeoff, but YMMV (if I do this again, I'll try having these hands just xfer to Ss, and see if I get noticeably different results).

In a), if opener had a poor S holding, I corrected to 2N, so when it came up, it could normally only make a difference if you made in 2S vs going off in 3S, or made an extra trick in 2S when opener didn't correct to 2n but would have passed it. (On most hands that followed this sequence, opener did have a poor S holding, so while it came up quite frequently, it made a difference on relatively few occaions). It might also matter if with a highly distributional hand you got to make an inv 2S bid (subsequently accepted) where you'd otherwise have given up on game and settled for a weak 2S bid, but this didn't come up.

a)
1 overtrick saved (in 2S vs 2N) x1

b)
This only came up once, and I accidentally hit redeal before I could read it out.

c)
1 undertrick saved x4
2 undertricks saved x1
1 overtrick saved x2
Part score saved (ie 2S making, 2H going off, and other methods end you in the latter) x2

* 'balanced' may be 22(54), which was key on a couple of the deals c) gained over/undertricks on, so if you prefer to open those 1m, downgrade c) appropriately.

I think in retrospect it might be a mistake to start with Stayman on 5S4H hands when not playing c), so I'd like to revisit this. Still it seems like c) is fairly dominant for the weak NT. Last caveat is that this fit with my prior expectations, so I've probably suffered some bias in my evaluations - would be interested to hear if a proponent of a) (or b, though I doubt it) has tried something similar and had different results.
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#26 User is offline   PhantomSac 

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Posted 2014-December-23, 20:56

Correcting to 2N seems pretty sweet
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#27 User is offline   benlessard 

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Posted 2014-December-23, 21:26

after 2C-2D-2H-??

you want opener to bid 2S more often than passing (33,32 vs 23). It will rightside 2M and allow responder to make a garb stayman with 3415/3406 hands. So its better to make stayman with 54?? than with 45??.

IMO what need to be sim is what should you do with a 45?? vs a partner that will correct to 2S holding 33??/32??.

Im strongly convinced 1NT-2red-2S should be inv 5S doesnt promise 4H. This allow 1NT-2H-2S-2NT to be forcing.
From Psych "I mean, Gus and I never see eye-to-eye on work stuff.
For instance, he doesn't like being used as a human shield when we're being shot at.
I happen to think it's a very noble way to meet one's maker, especially for a guy like him.
Bottom line is we never let that difference of opinion interfere with anything."
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#28 User is offline   aguahombre 

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Posted 2014-December-23, 21:46

View Postbenlessard, on 2014-December-23, 21:26, said:

Im strongly convinced 1NT-2red-2S should be inv 5S doesnt promise 4H. This allow 1NT-2H-2S-2NT to be forcing.

I am wondering why you would want that sequence to be forcing. It seems designed to extract leakage from Declarer in the most frequent cases where Spades or Notrump will be the strain.
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#29 User is offline   benlessard 

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Posted 2014-December-24, 01:26

1- It permit to make the difference between 5S+5m vs 5/6S+4m,
2- it keep a symmetry with 1NT--2D-2H--??; in that spot 2S or 2NT is available as a "gadget". So having the same "gadget" after a S transfer give some simplicity.
3- Also it permit opener to bid 3NT with exactly 5(332) allowing responder to pass with 3S and a square hand. Some bid 3m with any 5S??4 but I think its a poor method.

In general having the cheapest call as forcing "catch-all" is very powerful since it nearly double the number of available sequences.
From Psych "I mean, Gus and I never see eye-to-eye on work stuff.
For instance, he doesn't like being used as a human shield when we're being shot at.
I happen to think it's a very noble way to meet one's maker, especially for a guy like him.
Bottom line is we never let that difference of opinion interfere with anything."
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#30 User is offline   Fluffy 

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Posted 2014-December-24, 03:41

View PostPhantomSac, on 2014-December-23, 16:55, said:

@Fluffy, I think it's just better to have an agreement as to what opener is going to do with 3-3. I believe Fred and Brad play opener always corrects to 2S, so with 5 good hearts and 4 bad spades you would just transfer to hearts and take your chances. Most people do the opposite (so with 5 good spades and 4 weak hearts you transfer to spades and take your chances). I think this is better than opener always deciding in the moment what to do with 3-3, you get to the better fit more often if it is already pre-determined what opener does so that responder can adjust accordingly sometimes. Of course no matter what sometimes you will end in the wrong fit. Another thing is you don't want to be tanking on whether to pass or correct every time, it gives away to the defense that you are 3-3 which is very bad.


Well, this was just a theoric question to find out which major is lengthier, but I see this makes sense so I might just as well change it. Not worried much by 3-3 which actually take me a milisecond to decide based on quality, but 2-2s will be a lot worse when you are wrong.
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#31 User is offline   whereagles 

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Posted 2014-December-24, 04:31

Don't open NT on 2-2 majors then :)
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#32 User is offline   Jinksy 

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Posted 2014-December-24, 06:52

View Postbenlessard, on 2014-December-23, 21:26, said:

after 2C-2D-2H-??

you want opener to bid 2S more often than passing (33,32 vs 23). It will rightside 2M and allow responder to make a garb stayman with 3415/3406 hands. So its better to make stayman with 54?? than with 45??.


Rightsiding makes very little difference opposite a weak NT, and I'd be surprised if it was worth nearly as much opposite even a strong NT as just finding the best contract.

Not sure what you mean about 3415/3406. Do you mean 4315/4306? In our system, 3m after a Stayman response is weak TO, partly so that you can try your luck on shapes like these, but if I didn't have that available I wouldn't chance it on these hands - there's still too much chance of ending up in a 3-3 or 4-2 (or on a really bad day a 3-2) fit, when 1N was likely to have been a respectable contract.
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#33 User is offline   jogs 

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Posted 2014-December-24, 10:46

View Postsuokko, on 2014-December-22, 10:35, said:


But simulation shows:
$ cat simu.descr 
predeal north SAQJ,HJ93,DKQT8,CJ64

condition shape(south, 54xx + 45xx + 55xx) && hcp(south) < 9

action
	frequency "heart length" (hearts(south),4,5),
	frequency "spade length" (spades(south),4,5),
$ ./dealer < simu.descr 
Frequency heart length:
    4	  140195
    5	  164470
Frequency spade length:
    4	  124103
    5	  180562
Generated 10000000 hands
Produced 304665 hands
Initial random seed 1419266048
Time needed    3.185 sec


So more small cards in spades makes spade length more likely because of hcp limits.


Does this mean with this program you can easily create histograms?

1. Like total trumps for a board.
2. Sum of two long suits for a partnership.
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#34 User is offline   SixOfWands 

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Posted 2014-December-24, 13:50

View PostPhantomSac, on 2014-December-23, 16:52, said:

Obviously if you can bid 2S showing 5S and 4H weak you don't need to play this way. Some people use 2C then 2S as something more important than that hand type and sacrifice accuracy on weak 5/4 hands for gains on others.


That's very interesting PhantomSac, what other important use do you have for 2S in the sequence 1NT - 2C - 2D - 2S?

If you are going to use 2S as something else then i would play 1NT - 2C - 2D - 2H as specifically weak with five hearts (and four spades) rather than confusing your partner as to the length of your majors. With five spades and four hearts you could just transfer to spades, at least you will avoid horrible 4-3 fits when you partner guesses incorrectly with 3-3 in the majors.
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#35 User is offline   aguahombre 

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Posted 2014-December-24, 15:13

View PostSixOfWands, on 2014-December-24, 13:50, said:

That's very interesting PhantomSac, what other important use do you have for 2S in the sequence 1NT - 2C - 2D - 2S?

If you are going to use 2S as something else then i would play 1NT - 2C - 2D - 2H as specifically weak with five hearts (and four spades) rather than confusing your partner as to the length of your majors. With five spades and four hearts you could just transfer to spades, at least you will avoid horrible 4-3 fits when you partner guesses incorrectly with 3-3 in the majors.

This is heading toward the unthinkable/reactionary position that we should not bid Stayman at all with garbage hands unless short in clubs and willing to pass 2D. I know...hang the heretic.
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#36 User is offline   1stpanda 

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Posted 2014-December-24, 16:04

The argument about HCP in hearts is mainly specious - N is limited, else he would have invited. Every HCP he has in hearts is one less he can have elsewhere, within limits. (Of course, he might decide xxxx.Qxxxx.KQ.Qx is not worth an invite but Kxxx.AQxxx.xx.xx is.)

The real issue is that, with this hand, opener knows he's never, ever going to get a ruff in hand, whatever is trump. It's quite conceivable, however, that he could get a couple of ruffs in dummy. But if he does that, he'd far rather try to draw trump with AQJ than with Jxx. So I think it's obvious to try to play spades when your suit is this strong and you know that partner is weak.
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#37 User is offline   suokko 

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Posted 2014-December-24, 18:14

View Postjogs, on 2014-December-24, 10:46, said:

Does this mean with this program you can easily create histograms?

1. Like total trumps for a board.
2. Sum of two long suits for a partnership.


Fairly easy.

It depends how easy it is to calculate the value that you want. But there is tertiary selector operator for if-else statement and one can use check length of suits, HCP, controls, specific suit quality with simple functions. It's not turing complete programing language but powerful enough for most cases.

Bonus is ability to ask number of tricks for declarer. But that is poorly optimized feature making that kind of simulation fairly slow. The average speed is only about 10 contracts per second when the libdds can be a lot faster with the newer api.
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#38 User is offline   Jinksy 

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Posted 2014-December-24, 19:24

View PostPhilKing, on 2014-December-23, 18:09, said:

A lot of UK players of my acquaintance play 2 then 2 as inv with 5 spades, regardless of the heart holding, but that is irrelevant to this thread.


I've just been trying this some more when with 5S4H and weak I xfer rather than bidding Stayman, and it seems to be looking better so far (though it's harder to specify the hands, so there's a lot of random noise).

If you play this way, is there a standardish meaning for the sequence 1N 2H / 2S 2N?
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#39 User is offline   benlessard 

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Posted 2014-December-25, 02:17

Quote

Rightsiding makes very little difference opposite a weak NT, and I'd be surprised if it was worth nearly as much opposite even a strong NT as just finding the best contract.

Not sure what you mean about 3415/3406. Do you mean 4315/4306?


I dont see why responder cannot be quite weak, if the pts are splitted 13-6 rightsiding does have some value especially when its nearly free. With a 3416/3406 you can make a garbage stayman only if responder is expected to correct with 33, there is no danger of playing in a 6 card fit.

2C--2D-2H-2S-3C = to play.

The problem with using 2C-2y-3m as to play is that its a lot of bidding space for non-game hands. IMO facing a passed hand it might make sense but otherwise its too costly.
From Psych "I mean, Gus and I never see eye-to-eye on work stuff.
For instance, he doesn't like being used as a human shield when we're being shot at.
I happen to think it's a very noble way to meet one's maker, especially for a guy like him.
Bottom line is we never let that difference of opinion interfere with anything."
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#40 User is offline   Jinksy 

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Posted 2014-December-25, 04:30

Ah, I see. Yeah, that looks interesting. My guess is still that you're way overestimating the value of rightsiding. Weak hands opposite a weak NT are quite rare, both a priori and since the opps are more likely to compete when they have near half the points; also with a weak NT, opener rarely has more than one tenace, so with 20ish points, the opps will often have an easy lead.

Re using up space that's true, but there's only so many hand types you can sensibly put through Stayman, and slam-hunting hands opposite a weak NT are much rarer than weak takeouts, so I've been constantly finding that what looks like a good trade (a non-forcing weak TO bid for an F1 bid that gives you several new pathways to game) often isn't.
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