OGUST or Feature Showing

[helene_t]

Zel, you're hell bent on placing more reliance on an external source (external to BBO). Guess what? I am hell bent on placing more reliance on BBOs deal generator. You can test it for yourself.

1. Set up a "Teaching Table."

2. Click on "Deal Source."

3. Pick any hand.

4. Fill in the constraints.

...a) Number of ♠ = 6-13

......Number of HCP = 5-11

......Click on "Odds" = 2.97% X 3 = 8.91%

...b) Now add the following constraint as well

......Number of ♣ = 0-1

......Click on "Odds" = 0.77% X 3 = 2.31%

......Click on "Odds" = 0.77% X 3 X3 = 6.93%

 

I stand by my post. I don't believe Shortage Ask is playable!

FYP. You can have a six-card in three suits and the singleton in any of the three remaining suits, so you should multiply by 3x3=9, not by 3.

 

Technicalities aside you should know intuitively that something close to this must be correct. Is it really your experience that three quarters of all 6-baggers are 6322?

 

There are three 322 and three 331 distributions, and six 430 and six 421. But some 6430 and 6421 hands may be too flawed, especially if the 4-card suit is a major.

[manudude03]

It's not even like it cripples you entirely. I start by making the assumption you want to be in game opposite a maximum.

2D(multi)-2N:

3C/D: minimum with H/S.

3H/S: max with H/S (some reverse this).

...3C/D-3D/H asks if it's a good suit compared to the rest of their hand.

[PhilKing]

If you're still playing Multi then your legs are chopped off on what to use. Multi forces you to use good/bad type responses over the 2NT asking bid. Feature Ask or Shortness Ask do not exist for you.

 

That's not strictly true.

 

I give up a 3♣ response, which now shows specifically a game try in partner's major.

 

This frees up 2NT as a GF relay, over which more accurate definition can be obtained.

[manudude03]

Zel, you're hell bent on placing more reliance on an external source (external to BBO). Guess what? I am hell bent on placing more reliance on BBOs deal generator. You can test it for yourself.

1. Set up a "Teaching Table."

2. Click on "Deal Source."

3. Pick any hand.

4. Fill in the constraints.

...a) Number of ♠ = 6-13

......Number of HCP = 5-11

......Click on "Odds" = 2.97% X 3 = 8.91%

...b) Now add the following constraint as well

......Number of ♣ = 0-1

......Click on "Odds" = 0.77% X 3 = 2.31%

 

I stand by my post. I don't believe Shortage Ask is playable!

 

You need a basic lesson on probability. What that odds gave you was the probability that you have 5-11 HCP AND 6 spades AND 0-1 clubs. You should be dividing by the probability of having 5-11HCP and 6 spades (2.97%), or in technical terms P(0-1C|5-11HCP&6S). That gives you an actual probability of 25.926% for a singleton club.

 

The real percentage is slightly lower because of some freak distributions.

 

edit: numbers wrong, I put it in as 6-13 spades.

reedit: ok, did it properly this time, according to BBO hand generator, 5-11HCP and 6 spades is 2.38%, and 0-1 clubs added on is 0.57% giving a true probability of 23.95% (minus whatever for the "freaks"). Now multiply that by 3 for any singleton, and that becomes 71.85%

[fromageGB]

OK, when you have a weak 2, you have a shortage considerably more than half the time, but knowing the shortage is surely less important than knowing the strength. A strong (relatively) hand will give more tricks than a weak hand, but the tricks you make by ruffing in the shortage suit are worth no more than the tricks you would make from length otherwise.

[Phil352]

OK, when you have a weak 2, you have a shortage considerably more than half the time, but knowing the shortage is surely less important than knowing the strength. A strong (relatively) hand will give more tricks than a weak hand, but the tricks you make by ruffing in the shortage suit are worth no more than the tricks you would make from length otherwise.

 

This may be true, but personally I have found the real value of shortage ask is when partner (the 2nt bidder) holds something like xxx in a suit - opposite a shortage a thin game can be bid because we know our values are concentrated with the longer suits. If I show a feature in a different suit over his 2NT bid he is still left wondering about his xxx.

[PhilKing]

This may be true, but personally I have found the real value of shortage ask is when partner (the 2nt bidder) holds something like xxx in a suit - opposite a shortage a thin game can be bid because we know our values are concentrated with the longer suits. If I show a feature in a different suit over his 2NT bid he is still left wondering about his xxx.

 

If that is what you needed for game, then 2NT was an overbid.

[gnasher]

This may be true, but personally I have found the real value of shortage ask is when partner (the 2nt bidder) holds something like xxx in a suit - opposite a shortage a thin game can be bid because we know our values are concentrated with the longer suits. If I show a feature in a different suit over his 2NT bid he is still left wondering about his xxx.

I used to believe this, but then I realised that I'd never actually experienced this advantage. The hands where it occurs are rare, and when they occur you don't usually have enough for 2NT, and the opponents may be in the bidding anyway. And while we're waiting for the right deal to come along, we're leaking information on all the other deals where we don't care about singletons but we do care about overall strength.

 

In fact, the only reason I ever played a singleton ask was because Phil King had told me it was best, in about 1988.

[32519]

FYP. You can have a six-card in three suits and the singleton in any of the three remaining suits, so you should multiply by 3x3=9, not by 3.

Yeah, but you can't have them at the same time. Playing weak twos, you can have a six-card suit at ANY ONE TIME and the singleton in any of the remaining suits. :)

[32519]

Maybe we should ask the BBO programmers to relook at the mechanics sitting behind the odds calculator. Seems like I'm the only BBOer who believes that they are correct. :)

[sfi]

Don't worry about it. I directed 32519 to Chris Ryall's statistics page a month or so ago. A 6-10 Weak 2 in a major alone has a 3% probability. Just ignore any numbers posted here.

 

Turns out you can lead a horse to water...

[manudude03]

Maybe we should ask the BBO programmers to relook at the mechanics sitting behind the odds calculator. Seems like I'm the only BBOer who believes that they are correct. :)

 

What everyone is saying is you're not interpreting the numbers correctly. As I said, you have about a 2.38% chance of getting dealt 6 spades and 5-11HCP. But once you make your bid showing that, then the probability of you having it is 100%, and you need to scale your other percentages accordingly.

 

Yeah, but you can't have them at the same time. Playing weak twos, you can have a six-card suit at ANY ONE TIME and the singleton in any of the remaining suits. :)

 

I don't think Helene really explained it properly. It's not really so much as you need to multiply the singletons by 9, more that you shouldn't have multiplied the 6 card suit percentage by 3 (if you open 2S, you don't have 6 hearts or diamonds), but if you insist in doing so, then you must multiply the singletons by 3 (3 singletons to go with each suit)

[blackshoe]

An artificial bid showing a weak two in either major is not the same thing as a natural weak two in the suit bid. Put it another way: "weak two" is the name of a treatment, i.e., one of several possible natural meanings for a bid. By that name, a multi is not a "weak two" in spite of the fact that it is a two level bid that is, or usually is, weak.

[Winstonm]

Bidding always has a ripple effect. Multi changes the response structures, meaning that multi players cannot be as creative in responses as those who play a natural weak two. There are pluses and minuses to both methods.

 

The OP asked about weak twos: this probably should include multi weak twos but is unclear in the question.

[Vampyr]

An artificial bid showing a weak two in either major is not the same thing as a natural weak two in the suit bid. Put it another way: "weak two" is the name of a treatment, i.e., one of several possible natural meanings for a bid.

 

This is not strictly true. It is common to talk about "holding a weak two in spades" even when you are not playing an opening weak two. Similarly people talk about holding a weak NT or an Acol Two even if they do not include these among their opening bids.

[aguahombre]

This is not strictly true. It is common to talk about "holding a weak two in spades" even when you are not playing an opening weak two. Similarly people talk about holding a weak NT or an Acol Two even if they do not include these among their opening bids.

Excellent point. There is also something in this thread of value to Multi players whose 2M openings are also of the weak 2 ilk...merely different strength from 2D (Those pairs do exist). Those folks might well not want a size inquiry when they open 2M.

[campboy]

FWIW I ran some exact numbers. I'm taking as my definition of weak two that it has exactly 6 spades and no side 5-card or longer suit. This is pretty close to the shapes I open 2♠ on, and has the added benefit that it precludes having more than one shortage.

 

For a range of 5-11 there are 13718869776 such hands, of which 8619870420 have a shortage somewhere. That's about 62.8% of them. Making the range weaker pushes this proportion down slightly; it's about 62.5% for 0-9 (6995759400/11184476814).

[blackshoe]

This is not strictly true. It is common to talk about "holding a weak two in spades" even when you are not playing an opening weak two. Similarly people talk about holding a weak NT or an Acol Two even if they do not include these among their opening bids.

you misunderstand me. I did not say that someone who talks about holding a weak two in spades must necessarily have an agreement to open that hand two spades. I do say that "weak two" describes a particular hand type, and a multi 2♦ does not describe that type.

[32519]

Go and check out these Mathematical Probabilities and Percentages Tables on the Bridge Guys website.

 

Here is a quote from the document:

The numerous combinations of 52 cards and their probabilites and/or percentages of distribution and/or pattern and/or occurence have been studied by many mathematicians, arithmeticians, probability theorists, and mathematical statisticians. The source of the tables below are from The Official Encyclopedia of Bridge, published by the American Contract Bridge League in the year 1984.

 

Seems like BBOs deal generator is pretty reliable after all! B-) Once you start adding a specified HCP range to any specific hand pattern the percentage starts dropping. :lol:

[sfi]

Seems like BBOs deal generator is pretty reliable after all!

 

Nobody in this discussion is questioning the accuracy of BBO's deal generator. Interpretation of statistics can be a surprisingly tricky science at times though.

[Phil352]

I used to believe this, but then I realised that I'd never actually experienced this advantage. The hands where it occurs are rare, and when they occur you don't usually have enough for 2NT, and the opponents may be in the bidding anyway. And while we're waiting for the right deal to come along, we're leaking information on all the other deals where we don't care about singletons but we do care about overall strength.

 

In fact, the only reason I ever played a singleton ask was because Phil King had told me it was best, in about 1988.

 

Valid points gnasher, I think playing pretty constructive weak 2s (8+ to 11) tips it slightly back towards being slightly more frequent and useful since overall strength is already defined. If playing constructive style I'm not convinced feature ask is any more useful than shortage ask (i actually quite like the Svar convention which covers both shortages/6-4s and maximum/minimum. I ripped this from an old Brogeland card:

 

Svar:

2♠ = Natural, forcing one round (2NT, 3♥ and 3♠ is passable)

2NT = Asks for shortage and another suit

3♣ = Natural, GF

3♦ = Natural, GF

3♥ = Natural, GF (preempt over 2♥, which may be raised to game with at least 6-4)

3♠ = Preempt which may be raised to game with at least 6-4/Splinter over 2♥

3NT = To play (2NT followed by 3NT suggests to play)

4♣ = Splinter

4♦ = Splinter

4M = To play, no forcing pass.

 

 

2♥ – 2NT

3♣=6-4, 3♦ ask 3♥=♣, 3♠ = ♦, 3NT = ♠

3♦ = Shortage in a minor 3♥ ask

3♥ = Min with no shortage

3♠ = Shortage

3NT = Max with no shortage

4♣= Void

4♦= Void

4♥= Void in ♠

 

2♠ – 2NT

3♣= 6-4, 3♦ ask 3♥= ♣, 3♠ = ♦, 3NT = ♥

3♦ = Shortage in a minor 3♥ ask

3♥ = Shortage in ♥

3♠ = Min with no shortage

3NT = Max with no shortage

4♣= Void

4♦= Void

4♥= Void

4♠ = Void in ♥, min

[fromageGB]

Once you start adding a specified HCP range to any specific hand pattern the percentage starts dropping

I think what we are concerned with here is the usefulness of having a shortage ask, which boils down to the probability of having a shortage when you have a weak 2, not the probability of having a weak 2 in the first place, so the point range doesn't come into it.

 

Forget the multiplication by 9, that's confusing, caused by your confusion in post #21 where you multiplied 2.97 by 3. Keeping it simple, on your post #25's figures, corrected in manudude's post #29 for just 6 spades, rather than 6-13, the probability of a weak 2 in spades is 2.38%. Given this hand, a shortage in clubs is 0.57%. You could have a shortage in diamonds, and that is also 0.57%, and hearts is 0.57% too, so on the face of it the probability of any shortage is 0.57% * 3 = 1.71%. This is a bit of an overstatement, because the 0.57% that includes a shortage in clubs will also include rare hands that have a shortage in diamonds as well as a shortage in clubs (etc) so these are double-counted. So bring that shortage figure down from 1.71% to 1.68% (just a guess). The probability of a weak 2 in spades with any shortage = 1.68%. This means that the probability of a weak 2 in spades with no shortage = 2.38-1.68 = 0.70%, considerably smaller.

 

So when you have a weak 2 (in spades or any suit, the suit does not matter), the chance of a shortage is 1.68/2.38 = about 70%.

 

This means that a shortage ask is certainly to be considered, and can be useful. However, I believe it pales into insignificance compared with the trick taking difference effect of a wide point range, particularly a vast range such as 5 to 11. What might be useful is a combined method, where the 2NT inquiry commits to game opposite a top end, but depends on the right shortage opposite bottom end. eg 2♠ 2NT :

3♣/♦/♥ = shortage 5-8 hcp

3♠ = no shortage 5-8

3NT = AKQxxx no shortage

4♣/♦/♥ = shortage 9-11

4♠ = no shortage 9-11

[manudude03]

FWIW, I just did some number crunching on the generator with slightly stricter criteria.

 

6 spades, 0-4 H/D/C 5-11 HCP: 2.16%

6 spades, 0-4 H/D, 0-1 C 5-11HCP: 0.45% (you won't ever have another shortage, 6+1+4=11, so the 4th suit can only be as short as 2)

0.45*3=1.35%

1.35/2.16=62.5%

 

Those hands being double-counted were more than I thought.

[campboy]

Those hands being double-counted were more than I thought.

I don't think the double-count hands make much difference. The main problem with the original simulations is that they include all the hands with a 7-card suit, which are much more likely (about 85%) to have a shortage.

[manudude03]

I don't think the double-count hands make much difference. The main problem with the original simulations is that they include all the hands with a 7-card suit, which are much more likely (about 85%) to have a shortage.

 

The second set of numbers I used was for exactly 6 spades (but everything else in range ok), and the percentage has dropped about 10%. In fact thinking about it, I guess it shouldn't be that much of a surprise, as those 6511 hands and such shouldn't have been counted at all, let alone double-counted.