BBO Discussion Forums: A simple auction, but would you attempt the slam? - BBO Discussion Forums

Jump to content

Page 1 of 1
  • You cannot start a new topic
  • You cannot reply to this topic

A simple auction, but would you attempt the slam? with a pick-up partner; slam 2/2

#1 User is offline   mw64ahw 

  • PipPipPipPipPip
  • Group: Full Members
  • Posts: 939
  • Joined: 2021-February-13
  • Gender:Not Telling
  • Interests:Bidding & play optimisation via simulation.

Posted 2021-October-12, 06:44

This was a simple auction and I guess my bid would have been 4 rather than 3NT to indicate mild slam interest; rather than a direct 4 bid over 2NT.

Would I be too optimistic if aiming for a slam given hand revaluation takes us into slam territory?

Regardless it was a good evening with topping the rankings making it a pleasing session.
0

#2 User is offline   DavidKok 

  • PipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 2,235
  • Joined: 2020-March-30
  • Gender:Male
  • Location:Netherlands

Posted 2021-October-12, 06:56

2NT is called the 'slam killer' for a reason. It is impossible to properly evaluate the South hand on this auction. Both of you could have bid differently (4 over 3, and 4 over 3NT), but nothing reasonably gets you to slam. It happens.
0

#3 User is offline   Cyberyeti 

  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 13,900
  • Joined: 2009-July-13
  • Location:England

Posted 2021-October-12, 07:30

The best I could do is investigate and determine we're off an ace and Q (with 4 missing) where we play in 5.
0

#4 User is offline   mw64ahw 

  • PipPipPipPipPip
  • Group: Full Members
  • Posts: 939
  • Joined: 2021-February-13
  • Gender:Not Telling
  • Interests:Bidding & play optimisation via simulation.

Posted 2021-October-12, 07:41

I've just run the DD probability generator which gives a 92% chance of the slam presumably because opener's control count is above expected. Maybe not such a long shot after all?
0

#5 User is offline   mw64ahw 

  • PipPipPipPipPip
  • Group: Full Members
  • Posts: 939
  • Joined: 2021-February-13
  • Gender:Not Telling
  • Interests:Bidding & play optimisation via simulation.

Posted 2021-October-12, 09:38

View PostDouglas43, on 2021-October-12, 09:21, said:

Is that 92% of this particular slam making? That sounds a bit high for a slam missing an ace and Qxxx in trumps

Yep, but the Queen can be taken from either side even with a 3-1 break so the probability is higher
0

#6 User is offline   Winstonm 

  • PipPipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 17,190
  • Joined: 2005-January-08
  • Gender:Male
  • Location:Tulsa, Oklahoma
  • Interests:Art, music

Posted 2021-October-12, 09:40

If opps cash the club on opening lead, you are down to finding the Trump queen. As someone who spent most of his adult life hunting queens I can assure you 92% is a fantasy.
"Injustice anywhere is a threat to justice everywhere." Black Lives Matter. / "I need ammunition, not a ride." Zelensky
0

#7 User is offline   nige1 

  • 5-level belongs to me
  • PipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 9,128
  • Joined: 2004-August-30
  • Gender:Male
  • Location:Glasgow Scotland
  • Interests:Poems Computers

Posted 2021-October-12, 09:48

mw64ahw 'This was a simple auction and I guess my bid would have been 4 rather than 3NT to indicate mild slam interest; rather than a direct 4 bid over 2NT. Would I be too optimistic if aiming for a slam given hand revaluation takes us into slam territory? Regardless it was a good evening with topping the rankings making it a pleasing session.
++++++++++++++++++++++++
Congratulations on your win, mw64ahw :)
The slam is about 50% so you bid well to stay out of it.
Nevertheless, as North, IMO, you should break South's 3 transfer. If you don't show any enthusiasm, you risk missing game as well as slam :(

0

#8 User is offline   mikeh 

  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 12,836
  • Joined: 2005-June-15
  • Gender:Male
  • Location:Canada
  • Interests:Bridge, golf, wine (red), cooking, reading eclectically but insatiably, travelling, making bad posts.

Posted 2021-October-12, 11:20

View Postmw64ahw, on 2021-October-12, 07:41, said:

I've just run the DD probability generator which gives a 92% chance of the slam presumably because opener's control count is above expected. Maybe not such a long shot after all?

Lol.

Unless you are self-kibitzing, you should not pick up either 3-1 splits.

Slam requires either west to be void in hearts (cash the ace first) or a stiff Queen or a 2-2 break.

Far from hopeless but a heck of a lot worse than 92%
'one of the great markers of the advance of human kindness is the howls you will hear from the Men of God' Johann Hari
2

#9 User is offline   P_Marlowe 

  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 10,030
  • Joined: 2005-March-18
  • Gender:Male

Posted 2021-October-12, 12:25

I would have signed of in 4H quickly, if 3D followed by 4H showes SI,
I would go via 4D.
Given that you are in a pickup, starting with 3D followed by 4H is ok.
With kind regards
Uwe Gebhardt (P_Marlowe)
0

#10 User is offline   Winstonm 

  • PipPipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 17,190
  • Joined: 2005-January-08
  • Gender:Male
  • Location:Tulsa, Oklahoma
  • Interests:Art, music

Posted 2021-October-12, 12:49

View Postmikeh, on 2021-October-12, 11:20, said:

Lol.

Unless you are self-kibitzing, you should not pick up either 3-1 splits.

Slam requires either west to be void in hearts (cash the ace first) or a stiff Queen or a 2-2 break.

Far from hopeless but a heck of a lot worse than 92%


Exactly. The starting point is 52.5% - 2/2 hearts or a singleton queen.

If the queen is third in either hand your going down if you play correctly. Oddly, you have a better chance if the hearts are 4-0 as half the time you can pick them up. So that adds 5%.

It's an odd deal. If west and east both play low hearts, your odds of success drop to about 41%; however, if LHO show out on the first heart, your odds are 100%.

Now a little editorializing, i.e., opinion:


Regardless that this particular deal produced a 57.5% slam, personally I would not want to take a slam result - either making or going down - to a table to compare with solid teammates that I was hoping would continue to invite me onto their team. Although they would agree that this slam was worth bidding at 57.5% chance, thelr gut reaction to looking at the responding hand will be negative. The reason is that there is no way to know the critical nature of the Jxx of diamonds. As for evaluating the hand, you may as well have decided to try for slam with xx, KJ10xxx, xxx, Kx. That will not get you much in the way of future trust from teammates, and trust is what you want in and from your teammates. And it is what they are looking for when choosing with whom to play.
"Injustice anywhere is a threat to justice everywhere." Black Lives Matter. / "I need ammunition, not a ride." Zelensky
1

#11 User is offline   LBengtsson 

  • PipPipPipPipPip
  • Group: Full Members
  • Posts: 974
  • Joined: 2017-August-10
  • Gender:Male

Posted 2021-October-12, 13:08

how are you going to get to slam??? I can not see any sensible auction that gets there except if north super accepts on the transfer, which is not possible on this hand. without that most pairings will play in 4. period.
0

#12 User is offline   mw64ahw 

  • PipPipPipPipPip
  • Group: Full Members
  • Posts: 939
  • Joined: 2021-February-13
  • Gender:Not Telling
  • Interests:Bidding & play optimisation via simulation.

Posted 2021-October-12, 14:12

View Postmikeh, on 2021-October-12, 11:20, said:

Lol.

Unless you are self-kibitzing, you should not pick up either 3-1 splits.

Slam requires either west to be void in hearts (cash the ace first) or a stiff Queen or a 2-2 break.

Far from hopeless but a heck of a lot worse than 92%

Sounds like I need a new DD probability generator or time to sit down and do the maths myself
0

#13 User is offline   nullve 

  • PipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 2,228
  • Joined: 2014-April-08
  • Gender:Male
  • Location:Norway
  • Interests:partscores

Posted 2021-October-12, 14:23

View Postmikeh, on 2021-October-12, 11:20, said:

Unless you are self-kibitzing, you should not pick up either 3-1 splits.

View PostWinstonm, on 2021-October-12, 12:49, said:

If the queen is third in either hand your going down if you play correctly.



0

#14 User is offline   mikeh 

  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 12,836
  • Joined: 2005-June-15
  • Gender:Male
  • Location:Canada
  • Interests:Bridge, golf, wine (red), cooking, reading eclectically but insatiably, travelling, making bad posts.

Posted 2021-October-12, 14:31

View Postmw64ahw, on 2021-October-12, 14:12, said:

Sounds like I need a new DD probability generator or time to sit down and do the maths myself

No

You have to understand what double dummy simulations are

Say you hold AQJxxx opposite 109x.

Unless the bidding has told you otherwise, you’re going to run the 10, in the real world. This is a pure 50-50 play…I’m assuming you have no vacant space info but if, for example, you could infer that the hand in front of the AQJ held 3 cards in the suit, it’s a 75% finesse.

So you will, in real life, always lose to the stiff king if it is offside.

But a double dummy simulation ‘knows’ where the king is…if it’s offside, stiff, you drop it. If it’s onside, you finesse…double dummy means seeing all 52 cards and playing accordingly.

This is one reason, though hardly the only reason, that double dummy simulations are not even close to being as useful as a lot of people appear to think.
'one of the great markers of the advance of human kindness is the howls you will hear from the Men of God' Johann Hari
1

#15 User is offline   Cyberyeti 

  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 13,900
  • Joined: 2009-July-13
  • Location:England

Posted 2021-October-12, 14:36

View Postmw64ahw, on 2021-October-12, 14:12, said:

Sounds like I need a new DD probability generator or time to sit down and do the maths myself


Mike covers this, but it's 90%+ DD because any trump holding other than Q9xx over the KJ108 can be picked up, but unless you're self kibitzing, you won't have that success rate single dummy, it's about 52% (2-2 + stiff Q) less the chance of a first round ruff (or ace and another club ruffed).
1

#16 User is offline   nullve 

  • PipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 2,228
  • Joined: 2014-April-08
  • Gender:Male
  • Location:Norway
  • Interests:partscores

Posted 2021-October-12, 14:41

View Postsmerriman, on 2021-October-12, 14:39, said:

Why on earth would West play the Ace of clubs?

Try to give partner a club ruff, maybe?
0

#17 User is online   smerriman 

  • PipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 3,726
  • Joined: 2014-March-15
  • Gender:Male

Posted 2021-October-12, 14:49

Sorry, I deleted that like a minute after I posted it, you were too quick :P Still, it's not as if a 6-2 club break with that lead and play is going to affect the probability much.
0

#18 User is online   johnu 

  • PipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 4,833
  • Joined: 2008-September-10
  • Gender:Male

Posted 2021-October-12, 15:55

View Postmikeh, on 2021-October-12, 14:31, said:

This is one reason, though hardly the only reason, that double dummy simulations are not even close to being as useful as a lot of people appear to think.

True, double dummy simulations may be substantially off compared to single dummy play.

e.g.



Playing in NT, double dummy, 100% of the time the spades and hearts bring in 3 tricks in each suit because the location of the queens are known. Single dummy, barring some kind of squeeze/end play, declarer could misguess both suits and only take 2 tricks in each suit. On the other hand, in single dummy the opening leader or one of the defenders may lead one or both of the suits taking the guess out.

There have been a number of studies of real life hand results compared to after the fact double dummy analysis, and double dummy analysis comes reasonably close to real life results in the long run. The caveat is that on any given hand, double dummy results may produce ridiculous results from non percentage bridge plays that no expert would choose, or be lucky enough to guess 100%.

IMO, double dummy simulations are more useful in developing bidding systems and evaluating hands.

e.g. Partner opens 2NT showing 20-21 HCP. What random minimum high card count should responder raise to 3NT? Or, is it worth trying for slam?

Bird and Anthias published 2 books on opening leads based on double dummy computer simulations. The suggested opening leads were "interesting", but some of the suggestions worked out because the simulations assumed double dummy defense after the opening lead. Of course you are more likely to get the defense right after the opening lead and seeing dummy, but a lot of times it is a guess.
1

#19 User is offline   AL78 

  • PipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 1,962
  • Joined: 2019-October-13
  • Gender:Male
  • Location:SE England
  • Interests:Bridge, hiking, cycling, gardening, weight training

Posted 2021-October-12, 16:06

View Postmikeh, on 2021-October-12, 11:20, said:

Lol.

Unless you are self-kibitzing, you should not pick up either 3-1 splits.

Slam requires either west to be void in hearts (cash the ace first) or a stiff Queen or a 2-2 break.

Far from hopeless but a heck of a lot worse than 92%


There is a very small extra chance if you play the jack first and LHO with the queen covers, or fumbles with their cards before playing low telegraphing where the queen is. It might work against a weak pair.
0

#20 User is offline   mikeh 

  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 12,836
  • Joined: 2005-June-15
  • Gender:Male
  • Location:Canada
  • Interests:Bridge, golf, wine (red), cooking, reading eclectically but insatiably, travelling, making bad posts.

Posted 2021-October-12, 16:19

View PostAL78, on 2021-October-12, 16:06, said:

There is a very small extra chance if you play the jack first and LHO with the queen covers, or fumbles with their cards before playing low telegraphing where the queen is. It might work against a weak pair.

It won’t work against players I play against😀 in fact, if I did that, the opp would either feel insulted or would laugh at me. And if he held Q9xx, I advance the Jack, he ducks smoothly, I rise the Ace and now I have two losers. Not worth it even against weak players.
'one of the great markers of the advance of human kindness is the howls you will hear from the Men of God' Johann Hari
0

Page 1 of 1
  • You cannot start a new topic
  • You cannot reply to this topic

1 User(s) are reading this topic
0 members, 1 guests, 0 anonymous users