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xyz, 2/1 if it matters...

#21 User is offline   kenrexford 

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Posted 2012-July-21, 06:20

View Postrhm, on 2012-July-21, 05:55, said:

What are they please in a constructive auction?
Maybe you can be a bit more specific and more to the point of the goals of this particular sequence.
Cant is a very poor substitute for arguments.

Rainer Herrmann

I probably speak for few on this point, but as I personally would bid 1S in the discussed sequence with 3145 pattern often, the bid is not as restricted as you might think. But, my main objection is that you have somewhat of a fallacy. If we had a GF sequence, for example, then you have a point. But, with limited options, you have to split space effectively.

For instance, using your logic, one could say that 1NT should show balanced with precisely two spades, rebidding 1S with 3 spades and balanced, to increase the frequency of 1S bids. If two bids are available, and only two, you want 50% in each, not 80-20, because you lack space for the unwind. One might conclude (as do I) that your approach under-loads 1NT and overloads 1S, with insufficient space to unwind 1S effectively.

So, if someone finds your bidding theory postings not worthwhile because of a view that your analysis can be oversimplified at best to wrong at worst, I understand why, with this discussion being an example.
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#22 User is offline   cherdano 

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Posted 2012-July-21, 07:09

View Postrhm, on 2012-July-21, 05:55, said:

What are they please in a constructive auction?
Maybe you can be a bit more specific and more to the point of the goals of this particular sequence.
Cant is a very poor substitute for arguments.


If sequence A and sequence B reach the same contract, then obviously the sequence that gives out less information is superior.
In this particular sequence when opener has 4333 and responder doesn't have 5/6 hearts, then NT is quite likely the best or an adequate strain. Bidding 1NT over 1H will get there with minimum information leakage.

I thought all this to be obvious, and that we are just disagreeing about the trade-offs to be made.
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#23 User is offline   rhm 

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Posted 2012-July-21, 08:27

View Postgnasher, on 2012-July-21, 03:48, said:

In my experience it's not that frequent. On the hands where we have a fit and the points are evenly divided, the opponents will often have bid something already.

Given that declarer's distribution is given my simulations show that after a 1 response you will have a 4-4 fit in spades 20% of the time, when responder would pass 1NT.
I consider this frequent. Yes opponents will have a minor suit fit. What are they supposed to bid, particularly when their fit is in clubs?

Quote

Equally nobody ever provides real-life deals that support bidding 1. I suspect that the gains of both methods are fairly infrequent.

Come on. I only asked for deals to illustrate the advantage, not for real-life examples. Random simulations are good enough.
My simulations show an advantage for contracts, when responder will pass 1NT when a 4-4 fit in spades exists, on average of more than 1.5 tricks.
This is a very big difference, but no specific distribution is frequent, even 4=3=3=3 with 12-14 HCP is rare.

Just the first example of one of my simulations. I can provide many more.



Trick difference:3

Quote

That in itself is a cost. If bidding 1 on balanced hands means that you have to use 2 as artificial, you can no longer use it as a natural bid.

Of course any convention has a cost. XYZ is no exception. But the general consensus seems to be that opponents are unlikely to let you play 2 anyway when that would be a good contract.

Rainer Herrmann
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#24 User is offline   fromageGB 

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Posted 2012-July-21, 10:26

View Postcherdano, on 2012-July-21, 07:09, said:

In this particular sequence when opener has 4333 and responder doesn't have 5/6 hearts, then NT is quite likely the best or an adequate strain. Bidding 1NT over 1H will get there with minimum information leakage.

My objection is the use of the word "adequate". 2 usually gets more matchpoints than 1NT when there is a 4-4 fit, and while 1NT is "adequate", 2 is "better". At IMPS there is not much at stake here, and the side benefits of the implications when you do bid spades according to your methods may be more important. However, at matchpoints, give me the higher scoring contract any day.

Another advantage of finding the spade fit (if there is one) is that when 1NT is passed round to the protective position, it is easier to find a say 2 fit/sacrifice than it is when 2 is passed round. I think at part-score levels, being in a major has the advantage here.
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#25 User is offline   fromageGB 

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Posted 2012-July-21, 10:28

Sorry, I don't object to the use of the word "adequate", that is a good description when coupled with the connotation "but not the best".
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#26 User is offline   rhm 

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Posted 2012-July-21, 10:54

View Postkenrexford, on 2012-July-21, 06:20, said:

One might conclude (as do I) that your approach under-loads 1NT and overloads 1S, with insufficient space to unwind 1S effectively.

Hard to see how 1 can be overloaded, when it just shows the likely maximum number of spade cards you will hold in this sequence. What evidence do you have for this claim?
Statistical evidence is not on your side either and Bridge arguments stress the importance of major suit fits.
Even if you rebid 1 all the time with 4 cards in spades (I make some exceptions), 1 will occur about 55% of the time and 1NT 45% of the time.
1 includes all hands up to 19 HCP less the balanced hands in the 15-17 range with 4 cards in spades. (Depends a bit how light you open unbalanced)
In your case 1NT occurs 57% of the time and 1 around 43% of the time.

Rainer Herrmann
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#27 User is offline   kenrexford 

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Posted 2012-July-21, 13:03

View Postrhm, on 2012-July-21, 10:54, said:

Hard to see how 1 can be overloaded, when it just shows the likely maximum number of spade cards you will hold in this sequence. What evidence do you have for this claim?
Statistical evidence is not on your side either and Bridge arguments stress the importance of major suit fits.
Even if you rebid 1 all the time with 4 cards in spades (I make some exceptions), 1 will occur about 55% of the time and 1NT 45% of the time.
1 includes all hands up to 19 HCP less the balanced hands in the 15-17 range with 4 cards in spades. (Depends a bit how light you open unbalanced)
In your case 1NT occurs 57% of the time and 1 around 43% of the time.

Rainer Herrmann



First of all, if you are looking purely at shape and frequency, you forgot to add in the 1 rebids that I mkake with 3-1-5-4 hands. Also, you are assuming that I would not rebid 1 with some 4-2-3-4 hands (COV). Exceptions exist in both approaches.

More importantly, however, is the fact that the balanced hands without four spades are not comparable in unwind to the combination of balanced hands with four spades and unbalanced hands. Although your stated percentages might be accurate, the stats leave out the "work to be done" aspect of each case. When 1 is known (albeit with some rare exceptions) to be unbalanced, the unwinds are easier than if balanced is possible.

As a simple example, consider the unwinds when spades are in fact raised. When your holding could be a 4-3-3-3 HCP hand up to a fairly strong unbalanced hand, the unwind is more difficult than when the expectation is 11+ with spades and a stiff or void somewhere (usually), or 4-2-2-5. Less needs to be explained later.

Similarly, consider the aspect of having shown real clubs. In your auction, the club length is (2?)3+, whereas mine is (4?)5+. That might not sound that important to you, but in defense, considering game tries, considering patterning out, etc., there are subtle gains that cannot easily be explained with examples. (The fact that I can rebid 1 with 3-1-4-5 comfortably also helps because it enables a better handling of the near-reverse hand; e.g., 1-1, 1-1NT, 2 as just under contextual reverse strength. Although I could also bid that way using your methods, there is a degree of comfort bidding 1 when it advertises unbalanced, such that my one-card lie is within expectations, less so if 1 carries more weight.)
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#28 User is offline   Mbodell 

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Posted 2012-July-21, 22:28

View Postrhm, on 2012-July-21, 08:27, said:



Trick difference:3


If you open 1 - 1 - 1 - 2 I bet your opponents end up bidding 3 which will likely make at the table (2nt minor oriented t/o from E and then 3 from W might do it), and is cold for down 1 at worse. There are lots of folks with Larry Cohen's philosophy that -110 is worse than -1100 who will disturb you from 1M or 2M. Much less clear over 1 - 1 - 1nt.

This is a really hard style difference to analyze because it will effect so many hands and so many auctions. You have to count the times you induce a spade lead against nt when you have 4 spades but no fit, or when you scare off a spade lead because you haven't denied spades and the opening leader makes a different choice even though it turns out you didn't have spades. Or the extra inferences about unbalanced or not and real clubs or not when you bid spades.

Also, skipping the spade rebid will get you back to the part of the field that play the opposite nt strength (weak/strong) as you, since if the two hands do not have a game invite those folks will just open 1nt and be done with it. So it isn't even like you will not have company.
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#29 User is offline   SteveMoe 

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Posted 2012-July-25, 23:58

View Postinquiry, on 2012-July-13, 20:27, said:

I rebid 1NT with this shape, count. Always would seem to be the word I would apply to my choice.


Agree - seems when I have 4333 opposite a fitting 4432, NT and the major often make the same number of tricks. If trumps split 4-1 I might make more in NT. The extra vallue here is the inference that when I rebid 1 partner knows I am semi/unbalanced 4441, 5431, 5422, etc. (length in minor).

The other advantage is we often get a lead vs. 1NT, adding a trick.

A sim might be nice to see....
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#30 User is offline   mike777 

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Posted 2012-July-26, 02:00

View Postrduran1216, on 2012-July-13, 19:49, said:

holding a 4333 13 count, after the auction 1c p 1H p ?

Does it matter if values are scattered, or is this always a 1s/1nt call?



endless question that this thread has not ended

as a nonxpert i vote 1s......but.......
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#31 User is offline   SteveMoe 

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Posted 2012-July-27, 21:50

Andrew Gumperz has an article in Bridgewinners called
Keep It Simple

Here is an extract:

"Rebid 1NT. 1NT communicates your range and shape. If you rebid 1♠ you might hold 12-18 HCP and 3-7 clubs. With such a wide range of possibilities, partner is far more likely to have a difficult decision. True, you might lose a 4-4 spade fit, but if partner's hand is worth another bid, you can use a convention like New Minor Forcing to checkback and find it. Another benefit from an immediate 1NT lies in concealing the spade suit from the opponents when partner does not have 4 spades and you declare NT."

and...

"Rebid 1♠. Our guideline creates an important corollary: when opener rebids in a suit instead of NT, his hand is unbalanced. This hand, with its values in the long suits, is better shown by bidding clubs and spades than by rebidding 1NT. Since you would rebid 1NT with 4-3-3-3 shape, partner can be certain that you hold 4+ clubs to bid this way. This may help him reject NT when he also holds four clubs. Finally, 1♠ is more likely to right-side the contract, as partner's red-suit holdings are more likely to be vulnerable to attack than your club holding."
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