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One for the odds experts...

#1 User is offline   TylerE 

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Posted 2009-November-16, 21:27

Scoring: MP


1 (Agree?) - (2) - 2 - (4)
?

I bid 7, which made (partner had Jxx of and Qxxx of ).

I have a feeling the grand is about 90%. Anyone have any numbers, either with the speicifc hands or in general opp. a competitive raise?
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#2 User is offline   Jlall 

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Posted 2009-November-16, 22:13

you have more diamonds than spades
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#3 User is offline   rbforster 

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Posted 2009-November-16, 22:15

The odds of a trump loser are no higher than

9.6% (4-0 break) * 3/7 (partner doesn't have the J) = 4.1%

which still ignores the chance partner might have a 4th trump, the 4-0 break might be finesseable if you have the T9 between your hands etc.

Tackling the diamond suit is a little more complicated, and on the auction in question you also know that the opponents have 9+ (likely 10+) clubs between them making partner a slight favorite to hold diamond length in support of your side suit.
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#4 User is offline   rbforster 

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Posted 2009-November-17, 06:29

I have a hard time constructing hands with any number of diamonds where partner with 4 card trump support will fail, so it's really only the 3 card raises that can go wrong.

Rob F, on Nov 16 2009, 11:15 PM, said:

Tackling the diamond suit is a little more complicated, and on the auction in question you also know that the opponents have 9+ (likely 10+) clubs between them making partner a slight favorite to hold diamond length in support of your side suit.

Based on partner's number of diamonds,

0: 85%+ : 3-3 and a ruff, or 4-2 with 2 ruffs both seem reasonably likely to work (and 5-1/6-0 diamond breaks seem unlikely on the auction)
1: 68%+ : 3-2 and a ruff is certainly enough, although you may have other chances
2: 70%+ : 2-2 break (40%), or 3-1 break (50%) and either partner has Q (33%) or trumps break 2-2 (40%), plus a few smaller chances
3: 90%+ : partner has the Q (50%) or 2-1 break (80% of remaining) or extra chances if 3-0 and you can hook
4+: 100% barring an opening ruff

If you figure both opponents for their average of say 2xx5 shape and divide the red suits evenly, you can expect them to typically be something like 2425 or 2515(but not overcaller), and partner to be 3523 or 3433. I guess this suggests the 2-3 diamond cases are most likely.

If you asked me to guess, I'd say it was about 50-50 for partner to have an extra trump on this auction (with spade shortness likely by 4 bidder), so approximately

50% (4 trumps) * 100% prob of success +
50% (3 trumps) * [ 50% (2 diamonds) * 75% success + 50% (3 diamonds) * (90% success)]
============
~91%+

Your 90%+ estimate seems pretty good to me.
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#5 User is offline   fachiru 

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Posted 2009-November-17, 09:23

TylerE, on Nov 16 2009, 10:27 PM, said:

1 (Agree?)



No.
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#6 User is offline   TimG 

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Posted 2009-November-17, 09:41

There must be some chance of an opening diamond lead being ruffed that no one seems to be factoring in.

Edit: missed Rob's mention of a ruff, but still not considered in the %.
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#7 User is offline   rbforster 

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Posted 2009-November-17, 10:49

TimG, on Nov 17 2009, 10:41 AM, said:

There must be some chance of an opening diamond lead being ruffed that no one seems to be factoring in.

Edit: missed Rob's mention of a ruff, but still not considered in the %.

Yeah, I decided to ignore it. If we're talking about the more likely cases where partner as 2-3 diamonds, the specific 3-0 or 4-0 breaks are somewhere around 5-10% in those cases, and of course then they still have to find the lead at the table. In particular, on this auction where overcaller is on opening lead, he would need to have lots of diamond and still have longer clubs which is a pretty narrow target.
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#8 User is offline   aguahombre 

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Posted 2009-November-17, 11:05

What fun. At MP I get a near zero, at IMPS I would lose a couple, and at BAM would lose the board. Would end in 7D. I suck.
"Bidding Spades to show spades can work well." (Kenberg)
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#9 User is offline   pooltuna 

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Posted 2009-November-17, 11:31

Jlall, on Nov 16 2009, 11:13 PM, said:

you have more diamonds than spades

So!! It was a canape opening :)
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#10 User is offline   Vilgan 

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Posted 2009-November-17, 18:30

aguahombre, on Nov 17 2009, 12:05 PM, said:

What fun. At MP I get a near zero, at IMPS I would lose a couple, and at BAM would lose the board. Would end in 7D. I suck.

Same, except I think most would open it 1D so I expect to have a low MP score but push the board in a BAM unless Robinson has my hand at the other table.

Thank god partner had spaces to support, as I think it would have really clouded the waters if partner hadn't been able to support spades.
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#11 User is offline   TylerE 

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Posted 2009-November-17, 19:18

The problem I see with opening 1 is that how the heck are you ever gonna convince pard to play with a stiff or doubleton?
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#12 User is offline   Jlall 

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Posted 2009-November-17, 20:02

TylerE, on Nov 17 2009, 08:18 PM, said:

The problem I see with opening 1 is that how the heck are you ever gonna convince pard to play with a stiff or doubleton?

If he has a doubleton or stiff spade why would I want to play in spades, unless he has 2 spades and 1 diamond in which case I think it will be pretty easy to convince him!
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#13 User is offline   inquiry 

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Posted 2009-November-17, 20:22

fachiru, on Nov 17 2009, 10:23 AM, said:

TylerE, on Nov 16 2009, 10:27 PM, said:

1 (Agree?)



No.

The problem with opening 2 is that it is susceptible to huge preempts, so I don't mind opening one level to rebid something else at a very high level if necessary or prudent later.

Without science, open 1 and after being raised, rebid 7 is a reasonable shot (partner can correct or pass).

However, I could mention MisIry (oh no, not again... I guess I will give just a slither that fits this hand).... open 3 and rebid 6 shows a / two suiter with one loser -- AND that loser is not in 's.

With AK or Q in either suit, partner knows were to go. With J and Q, you would end up in 7, if responder had xxx of spades and Qxx of diamonds, responder would bid 6NT asking opener to bid grand in suit he has the jack, lacking that ask opener to bid grand in his longer suit.

(NOTE:

3=any
  • 5 = / two suiter, one loser, need either ACE or King of clubs
  • 6* = / two suiter, one loser, no need for a honor

*other bids from 5 to 6 show minor two suiters with one loser

BTW, 3D-any-6D-6H shows spade fit, and is asking if heart ACE is useful, obviously no club is needed, and responder can not have AKQ or either anchor suit or no need to ask. )
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#14 User is offline   rbforster 

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Posted 2009-November-18, 09:56

Rob F, on Nov 17 2009, 11:49 AM, said:

TimG, on Nov 17 2009, 10:41 AM, said:

There must be some chance of an opening diamond lead being ruffed that no one seems to be factoring in.

Edit: missed Rob's mention of a ruff, but still not considered in the %.

Yeah, I decided to ignore it. If we're talking about the more likely cases where partner as 2-3 diamonds, the specific 3-0 or 4-0 breaks are somewhere around 5-10% in those cases, and of course then they still have to find the lead at the table. In particular, on this auction where overcaller is on opening lead, he would need to have lots of diamond and still have longer clubs which is a pretty narrow target.

In addition, I thought I would add one more reason to likely ignore the ruff. When advancer bounces preemptively with 4, he is usually doing so with shortness in the opponents' suit (spades). So you might expect him to be 1xx5 or something typically. In particular, since the ruff would be in diamonds and advancer has advertised short spades, it's not that likely he'll also be void in diamonds. Is he really 1507 or 1606? These are pretty unlikely shapes and given advancer is the one who needs the void, it seems pretty unlikely to me. A heart ruff is basically impossible since there are so many hearts to split only 3 ways and since no one bid them they must be pretty well divided.
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#15 User is offline   bid_em_up 

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Posted 2009-November-18, 10:45

TylerE, on Nov 17 2009, 08:18 PM, said:

The problem I see with opening 1 is that how the heck are you ever gonna convince pard to play with a stiff or doubleton?

I really don't think this is an issue Tyler.

When you first proposed this hand to me, I said I would open 1 and you said the auction would go as follows:

1 (2) 2 (4)

Given this start, I bid 4 and I refuse to believe any competent partner will ever pass this as you suggested he might. You did not state what the opponents will do over 4 (if anything), but it is a moot point.

Over whatever partner bids, you simply bid 7, unless the opponents beat you to it in which case you're forced to guess.

This sequence should convey the message that you have longer diamonds than spades but the spades are solid if partner has any length at all in the suit and should be pick a slam.

jmoo.
Is the word "pass" not in your vocabulary?
So many experts, not enough X cards.
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#16 User is offline   hanp 

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Posted 2009-November-18, 10:53

After 1D - (2C) - 2D - (4C) I would bid 6S.
and the result can be plotted on a graph.
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#17 User is online   mikeh 

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Posted 2009-November-18, 11:12

hanp, on Nov 18 2009, 11:53 AM, said:

After 1D - (2C) - 2D - (4C) I would bid 6S.

Well, I am not entirely sure that I agree with 6...altho it is perhaps 1000 times better than the (incredible) 4 suggestion.

Frankly, I'd make the bid I suspect most would make at the table....7.

I'd give up on finding partner with the 'right' spade holding to raise (what is he really going to bid with Jx in spades or even Jxx.....let alone xxx... couldn't you be AKxxxx void AKJxxxx void or AKQxx A AKxxxxx void?) and I surely do not want to bid 6, hear partner bid 7 and now hear the opps bid 7, 'knowing' that I have 12-13 pointed cards.
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#18 User is offline   hanp 

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Posted 2009-November-18, 11:13

I would bid 7D at IMPs but at matchpoints I would rather bid 7S than 7D.
and the result can be plotted on a graph.
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#19 User is offline   Jlall 

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Posted 2009-November-18, 13:33

So you're sure 6S is forcing Han? I guess logically it is but I'd be scared!

Also do you think 1N-2D-2H-6N is logically forcing and pick a grand? If so, what would you think of the argument that you can bid 1N-2D-2H-5N then raise whatever to 7?

I'm just saying someone could easily interpret that auction as forcing, while someone else could reasonably argue it's not, and maybe it's the same in this case. At the very least I would be worried it's a situation partner has never seen before and he might go wrong.
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#20 User is offline   hanp 

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Posted 2009-November-18, 16:51

Jlall, on Nov 18 2009, 02:33 PM, said:

So you're sure 6S is forcing Han? I guess logically it is but I'd be scared!

Playing with you I'd bid 7S Justin. You are of course right that it depends greatly on who you are playing with and how well you know him or her. Maybe 5S is more clearly forcing?

As for 2H followed by 6NT, I wouldn't try that one on any partner undiscussed. Maybe I would try for 7H if partner superaccepted? That may be farfetched, but especially at matchpoints I would never try this auction undiscussed, and I'm not planning to discuss it any time soon. 2H followed by 5NT followed by a raise seems safer.
and the result can be plotted on a graph.
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