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math or simulation for this

#1 User is offline   Fluffy 

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Posted 2014-December-22, 07:00

I open 1NT 14-16 with

AQJ
J93
KQ108
J64


Partner bids 2-2-2 showing at least 5-4 in the majors and a weak hand (less than 9)

Will partner have more hearts or spades on average?
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#2 User is offline   Vampyr 

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Posted 2014-December-22, 07:12

View PostFluffy, on 2014-December-22, 07:00, said:

I open 1NT 14-16 with

AQJ
J93
KQ108
J64


Partner bids 2-2-2 showing at least 5-4 in the majors and a weak hand (less than 9)

Will partner have more hearts or spades on average?


Hearts, I think, because if the spades are any good partner might have bid 2 over 2 (if available) or transferred initially.

EDIT: similarly, if the default is to bid rebid hearts with 3-3, then with 4-5 partner is guaranteed to find an 8-card fit if there is one. With 5-4 there is no such guarantee, so less of a reason to keep hearts in the picture.
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#3 User is offline   PhilKing 

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Posted 2014-December-22, 07:12

I can think of 2 reasons for "more hearts" off the top of my head, but none for "more spades" yet.
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#4 User is offline   Jinksy 

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Posted 2014-December-22, 07:13

What would be the parameters of the simulation?

My guess would be s, since if he had 4, there's a chance opps would have overcalled in the suit, which looks much less likely in s.
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#5 User is offline   mgoetze 

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Posted 2014-December-22, 07:29

View PostVampyr, on 2014-December-22, 07:12, said:

partner might have bid 2 over 2 (if available)

Really can't even begin to answer this question without knowing what other options partner had (for me 2 would have shown much the same but 2 would have been invitational with 5 spades).
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#6 User is offline   gszes 

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Posted 2014-December-22, 08:44

Idealistically partner is using the system to best advantage, that means
they will not use this particular system with 4 lousy hearts and 5 lousy spades
vastly preferring to transfer to spades in that situation since it is quite
risky taking a chance on playing a lousy 7 card heart fit and missing a lousy
8 card spade fit. Responder will have no qualms with 4 lousy spades and 5 lousy
hearts since there is no risk of missing the 8 card heart fit.

Hearts should have 5 more frequently than spades but how often is a matter of
personal taste. Where would you draw the line between a simple transfer and
using stayman with the following hands?

AKQ2 87654 32 32
AK32 87654 32 32
AQ32 87654 32 32
QJT2 87654 32 32

and will your answer depend on vulnerability?
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#7 User is offline   whereagles 

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Posted 2014-December-22, 09:04

If the bid can be 0 hcp, then the odds are exactly the same. If some hcp are required for it, then perhaps hearts are more likely, but the difference will always be infinitesimal.

Probably the real question is "should I keep playing this system?", to which I would firmly say "no". Posted Image
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#8 User is offline   Radrag 

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Posted 2014-December-22, 09:19

View PostFluffy, on 2014-December-22, 07:00, said:

I open 1NT 14-16 with

AQJ
J93
KQ108
J64


Partner bids 2-2-2 showing at least 5-4 in the majors and a weak hand (less than 9)

Will partner have more hearts or spades on average?


I'm assuming that partner will bid like this EVERY time he has 54+ in the majors and less than 9.

There are more unknown x's in spades, so there are more ways to construct a weak hand with 5(+)spades than 5(+)hearts.
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#9 User is offline   Radrag 

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Posted 2014-December-22, 09:23

View Postwhereagles, on 2014-December-22, 09:04, said:

If the bid can be 0 hcp, then the odds are exactly the same.


The fewer hcp partner has the more likely spades are longer than hearts.
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#10 User is offline   jogs 

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Posted 2014-December-22, 09:46

Question: does partner ever transfer with 5=4 or 4=5?

If not, both patterns are equally likely.
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#11 User is offline   Fluffy 

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Posted 2014-December-22, 09:48

View PostJinksy, on 2014-December-22, 07:13, said:

What would be the parameters of the simulation?



View PostFluffy, on 2014-December-22, 07:00, said:

at least 5-4 in the majors and a weak hand (less than 9)

You can discount 6-4, 7-5 and 7-4 I guess but I don't think they are going to change which suit is longer if any.
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#12 User is offline   suokko 

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Posted 2014-December-22, 10:35

I have agreement that biding promises more spades than hearts. We transfer to hearts with a weak hand and 5 hearts and 4 spades. Only mildly invitational with 5 hearts and 4 spades bids stayman. So this question is more about agreement details than actual random parameters.

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.
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#13 User is offline   PhilKing 

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Posted 2014-December-22, 10:56

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

I have agreement that biding promises more spades than hearts. We transfer to hearts with a weak hand and 5 hearts and 4 spades. Only mildly invitational with 5 hearts and 4 spades bids stayman. So this question is more about agreement details than actual random parameters.

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.


Were this the only variable factor, it would be a slam dunk.

However, it ignores the opponent's bidding. With a borderline hand, depending on methods, an opponent would be more likely to enter the bidding with a chunky 4 card major plus a 5-card minor, for instance. And they can't only have a chunky major if it is hearts. The argument also holds with 5M4m hands.

Also, assuming OP plays Stayman followed by 2 as invitational with five, there is a gap when holding the equivalent hand with 9 points and 45 in the majors. It is quite rational to go low and bid Stayman followed by 2 with that agreement.

Having said all that, my gut instinct is that the spade blockers trump my arguments.
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#14 User is offline   suokko 

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Posted 2014-December-22, 11:11

View PostPhilKing, on 2014-December-22, 10:56, said:

Were this the only variable factor, it would be a slam dunk.

However, it ignores the opponent's bidding. With a borderline hand, depending on methods, an opponent would be more likely to enter the bidding with a chunky 4 card major plus a 5-card minor, for instance. And they can't only have a chunky major if it is hearts. The argument also holds with 5M4m hands.

Also, assuming OP plays Stayman followed by 2 as invitational with five, there is a gap when holding the equivalent hand with 9 points and 45 in the majors. It is quite rational to go low and bid Stayman followed by 2 with that agreement.

Having said all that, my gut instinct is that the spade blockers trump my arguments.


I never even try to make perfect simulation that takes all unlikely parameters into account. To me opponents passing in this situation is balanced enough effect to both lengths. It would probably have more effect to hcp frequency for south making the lowest values less likely. Of course that reduces slightly spade blockers effect but it isn't going to reverse the effect.
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#15 User is offline   benlessard 

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Posted 2014-December-23, 00:50

A more important question is ..is it ok to do Garbage stayman with both 54 and 45 ? or should you transfer with one shape but not the other.

Also responder pts matter here, with some values like 6-8 pts maybe he can play it safe and transfer knowing 2M in a 5-2 fit is less likely to go down, the main fear would be to avoid the 4-3. The cost of missing the 4-4 is lower. With a weaker hand however aiming for the 4-4 fit has more upside since it could be your only hope to get a plus score.

Also maybe with (54)22, 6-8 pts and poor majors maybe passing 1NT is the percentage call at imps if you play GS as 54 or 45.
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#16 User is offline   The_Badger 

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Posted 2014-December-23, 12:22

hi Fluffy,

As I know a fair amount about statistics and computers I will provide you with an analogy. I bought a lucky dip lottery ticket once and the computer-generated ticket was 6 consecutive numbers! The point I'm making is that simulations are only that, they cannot compete with raw statistics. I was very unlikely to ever win with that ticket BUT it is one of the 14 or so million combinations of numbers that are available, so it actually stands just as much chance as any other ticket in theory.

If you partner ALWAYS bids 2 with any 5-4 majors of less than 9 points, and does not deviate from that premise, whatever cards and honour cards he holds, there is an equal chance of him holding 5/4 or 45.

However, if he has AN ADDITIONAL OPTION to make a major suit transfer if he has honour cards in a suit, then he is more likely to have a 5 card suit on probabilities.
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#17 User is offline   Free 

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Posted 2014-December-23, 12:35

In my partnership s are longer or equal in length to s. With 5-4 we transfer to and hope we didn't miss a better fit. This way opener should always correct to 2 after the above auction and know it's the best action for sure.

You can play the other way around for sure, for example if you think it's better that the weak hand declares (unknown strength).

Without such agreement, chances are equal.
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#18 User is offline   PhilKing 

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Posted 2014-December-23, 16:37

View PostThe_Badger, on 2014-December-23, 12:22, said:



If you partner ALWAYS bids 2 with any 5-4 majors of less than 9 points, and does not deviate from that premise, whatever cards and honour cards he holds, there is an equal chance of him holding 5/4 or 45.


This statement is "true", but it is not true when we hold this hand for the reason given by Radrag and Suokkoi.

There are more combinations of weak hands containing 5 spades than there are holding 5 hearts. In a word, "blockers". If you don't trust simulations you can do it this way - put the missing cards in three piles: spades, hearts and minors. Then deal four cards from each pile then mix the remaing major cards and deal one card. You will find more heart hands invalidated for being too strong than vice versa.
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#19 User is offline   SixOfWands 

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Posted 2014-December-23, 16:40

View PostFluffy, on 2014-December-22, 07:00, said:

I open 1NT 14-16 with

AQJ
J93
KQ108
J64


Partner bids 2-2-2 showing at least 5-4 in the majors and a weak hand (less than 9)

Will partner have more hearts or spades on average?


If you're playing a weak version of Stayman where you can bid 2C with 54 in the majors (either suit longer) then you should always bid your five card major on this sequence.

1NT - 2C - 2D - 2H should promise five+ hearts.

Partner does not have a four card major and a 5-2 fit plays better than a 4-3 fit. You might still have a fit in your five card major but you definitely don't in your four card suit. So just agree to bid the longer one, its simple if you do that. This is the standard approach in the UK.
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#20 User is offline   PhantomSac 

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Posted 2014-December-23, 16:52

View PostSixOfWands, on 2014-December-23, 16:40, said:

If you're playing a weak version of Stayman where you can bid 2C with 54 in the majors (either suit longer) then you should always bid your five card major on this sequence.

1NT - 2C - 2D - 2H should promise five+ hearts.

Partner does not have a four card major and a 5-2 fit plays better than a 4-3 fit. You might still have a fit in your five card major but you definitely don't in your four card suit. So just agree to bid the longer one, its simple if you do that. This is the standard approach in the UK.


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.
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