BBO Discussion Forums: 6H Play (free - kgr) - BBO Discussion Forums

Jump to content

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

6H Play (free - kgr) Probability calculation or estimate

#1 User is offline   kgr 

  • PipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 3,429
  • Joined: 2003-April-11

Posted 2011-January-30, 03:21


6 or 7 would have been better contracts, but we arrived at 6
(You can comment on the bidding, but I'm most interested in the play first. About the bidding: I preferred to show my length first and planned to bid next, but that was not possible anymore.)
West leads K that you take with the A (East following with a small ).
Next I played A and throw J from North. Both opps following with a small .
Is it now best to continue with:
- K
- or with a small to A, followed by A and finesse?
0

#2 User is offline   gordontd 

  • PipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 4,485
  • Joined: 2009-July-14
  • Gender:Male
  • Location:London

Posted 2011-January-30, 05:12

View Postkgr, on 2011-January-30, 03:21, said:

(You can comment on the bidding, but I'm most interested in the play first. About the bidding: I preferred to show my length first and planned to bid next, but that was not possible anymore.)

I can't think why it was not possible: 3 rather than 3 would have done the trick.
Gordon Rainsford
London UK
0

#3 User is offline   kgr 

  • PipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 3,429
  • Joined: 2003-April-11

Posted 2011-January-30, 05:39

View Postgordontd, on 2011-January-30, 05:12, said:

I can't think why it was not possible: 3 rather than 3 would have done the trick.

I thought my sentence said that it was not possible anymore to show after I started with 3?
I preferred to start with 3 because I thought I would show a 5-5 otherwise. Or have to bid a non-forcing 4 to show a 6c. But I agree that 3 is better (certainly after the DBL of partner), partner will support sometime with a doubleton and no .
0

#4 User is offline   gnasher 

  • Andy Bowles
  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 11,993
  • Joined: 2007-May-03
  • Gender:Male
  • Location:London, UK

Posted 2011-January-30, 05:42

Cashing a second heart gains when LHO has three diamonds and Qx. It loses when hearts are Qxxx-x, either way around.

If we ignore both the overcall and any vacant-space considerations, the chance that LHO has three diamonds and Qx is roughly:
  Diamonds 3=1: 25%
  Hearts 2=3: 44%
  Q in the short hand = 40%
25% * 44% * 40% ~= 4.5%

The chance of someone having Qxxx is:
  Hearts 4-1: 28%
  No singleton queen: 80%
28% * 80% ~= 22%

That's such a large difference that we can assume that hearts 4-1 is more likely, without doing any more accurate calculations. Hence I would play the finesse line.
... that would still not be conclusive proof, before someone wants to explain that to me as well as if I was a 5 year-old. - gwnn
0

#5 User is offline   karlson 

  • PipPipPipPipPip
  • Group: Full Members
  • Posts: 974
  • Joined: 2005-April-06

Posted 2011-January-30, 05:48

Seems clear to finesse.

If I'm not mistaken we're comparing lefty having x vs (Qx+xxx). x and Qx are approximately equally likely a priori (4 cases) and 3 diamonds with lefty is only ~20%. Any empty spaces considerations will swing it even more as it's less likely the 1 bidder has length in both reds.

Edit after seeing gnasher's: oops, right, Qxxx with lefty is important too. Even less close.
0

#6 User is offline   kgr 

  • PipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 3,429
  • Joined: 2003-April-11

Posted 2011-January-30, 08:43

View Postgnasher, on 2011-January-30, 05:42, said:

Cashing a second heart gains when LHO has three diamonds and Qx. It loses when hearts are Qxxx-x, either way around.

If we ignore both the overcall and any vacant-space considerations, the chance that LHO has three diamonds and Qx is roughly:
  Diamonds 3=1: 25%
  Hearts 2=3: 44%
  Q in the short hand = 40%
25% * 44% * 40% ~= 4.5%

The chance of someone having Qxxx is:
  Hearts 4-1: 28%
  No singleton queen: 80%
28% * 80% ~= 22%

That's such a large difference that we can assume that hearts 4-1 is more likely, without doing any more accurate calculations. Hence I would play the finesse line.

4.78% for Diamonds 0-4
4.78% for Diamonds 4-0, but RHO would have given a Lightner DBL then. 1% is enough for 4-0
=> That leads to ~10% vs ~22% in favor of finesse?
0

#7 User is offline   gnasher 

  • Andy Bowles
  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 11,993
  • Joined: 2007-May-03
  • Gender:Male
  • Location:London, UK

Posted 2011-January-30, 09:26

View Postkgr, on 2011-January-30, 08:43, said:

4.78% for Diamonds 0-4
4.78% for Diamonds 4-0, but RHO would have given a Lightner DBL then. 1% is enough for 4-0
=> That leads to ~10% vs ~22% in favor of finesse?

If diamonds are 0=4 or 4=0, you will also need Q to be doubleton - otherwise you will have two losers. Hence you should multiply those figures by (0.4 * 0.44).
... that would still not be conclusive proof, before someone wants to explain that to me as well as if I was a 5 year-old. - gwnn
0

#8 User is offline   kgr 

  • PipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 3,429
  • Joined: 2003-April-11

Posted 2011-January-30, 10:36

View Postgnasher, on 2011-January-30, 09:26, said:

If diamonds are 0=4 or 4=0, you will also need Q to be doubleton - otherwise you will have two losers. Hence you should multiply those figures by (0.4 * 0.44).

Yes, right.
I played and LHO had void and RHO had Qx.
My teammates said it was obvious to play AK
0

#9 User is offline   FrancesHinden 

  • Limit bidder
  • PipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 8,482
  • Joined: 2004-November-02
  • Gender:Female
  • Location:England
  • Interests:Bridge, classical music, skiing... but I spend more time earning a living than doing any of those

Posted 2011-January-30, 13:02

Just tell your teammates you were one off in 7D
0

#10 User is offline   gnasher 

  • Andy Bowles
  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 11,993
  • Joined: 2007-May-03
  • Gender:Male
  • Location:London, UK

Posted 2011-January-30, 13:49

I can think of something else that you might tell your teammates.
... that would still not be conclusive proof, before someone wants to explain that to me as well as if I was a 5 year-old. - gwnn
1

#11 User is offline   HeartA 

  • PipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 2,016
  • Joined: 2004-October-17

Posted 2011-January-31, 00:11

View Postkgr, on 2011-January-30, 05:39, said:

I thought my sentence said that it was not possible anymore to show after I started with 3?
I preferred to start with 3 because I thought I would show a 5-5 otherwise. Or have to bid a non-forcing 4 to show a 6c. But I agree that 3 is better (certainly after the DBL of partner), partner will support sometime with a doubleton and no .

3 was very wrong. With 6-5, you always bid 2nd suit at second chance (bid it again at 3rd chance). Or else you would never be able to show the 5-card suit.
Senshu
0

#12 User is offline   Free 

  • mmm Duvel
  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 10,728
  • Joined: 2003-July-30
  • Gender:Male
  • Location:Belgium
  • Interests:Duvel, Whisky

Posted 2011-January-31, 08:11

Yeah, we had a very weird auction (imo) and ended up in 6 instead of 7. Your team mates were a bit more aggressive, they raised ! Why didn't you open this as a GF 2-suiter anyway, I thought you had the tools?



Imo the suit is the best suit to play once partner Doubled. We should have 9 of them, and we only need A to make grand in many cases. Partner won't have 3, but he may have Q/A/K/5s/... I think rebidding is a poor choice.

I believe partner was a passed hand, and I was still thinking of grand slam :D

EDIT: I don't believe cashing AK is that much better. You'll lose against all but one 4-1 trump splits, which is more common than a 4-0 split (~26.53% vs ~9,56%).
"It may be rude to leave to go to the bathroom, but it's downright stupid to sit there and piss yourself" - blackshoe
0

#13 User is offline   kgr 

  • PipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 3,429
  • Joined: 2003-April-11

Posted 2011-January-31, 11:21

View PostFree, on 2011-January-31, 08:11, said:

Yeah, we had a very weird auction (imo) and ended up in 6 instead of 7. Your team mates were a bit more aggressive, they raised ! Why didn't you open this as a GF 2-suiter anyway, I thought you had the tools?
First of all, congrats again with your score.
I thought the bidding would go better by opening 1.
With our 2 structure this goes:
2-2
3-4 (3=GF with and a Major.)
...

View PostFree, on 2011-January-31, 08:11, said:



Imo the suit is the best suit to play once partner Doubled. We should have 9 of them, and we only need A to make grand in many cases. Partner won't have 3, but he may have Q/A/K/5s/... I think rebidding is a poor choice.

I agree now that bidding is better than rebidding

View PostFree, on 2011-January-31, 08:11, said:

EDIT: I don't believe cashing AK is that much better. You'll lose against all but one 4-1 trump splits, which is more common than a 4-0 split (~26.53% vs ~9,56%).
This is a strange way to say that cashing AK is worse?
0

#14 User is offline   Free 

  • mmm Duvel
  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 10,728
  • Joined: 2003-July-30
  • Gender:Male
  • Location:Belgium
  • Interests:Duvel, Whisky

Posted 2011-February-01, 13:22

View Postkgr, on 2011-January-31, 11:21, said:

This is a strange way to say that cashing AK is worse?

Yes :P
"It may be rude to leave to go to the bathroom, but it's downright stupid to sit there and piss yourself" - blackshoe
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