BBO Discussion Forums: Claculation Question - BBO Discussion Forums

Jump to content

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

Claculation Question

#1 User is offline   onaykk 

  • Pip
  • Group: Members
  • Posts: 5
  • Joined: 2018-February-12

Posted 2018-February-12, 03:57

Hello,

I am relatively new in Bridge but I am quite obsessed lately about the claculations and possiblities. I have a problem:

Whenever lets say you have 5 H in the bid and you and your partner has 10 H in your hands. Lets say Hands are A Q 8 7 6 5 in your hand and partner is J 10 9 2 . There is K 4 and 3 out. Lets say turn is yours. In this situation hitting A is a better probability that one of the opponents have K or the bigger percentage is trying to go to your partners hand and try to do Empass , and gambling to get K from the one opponent?
0

#2 User is offline   onaykk 

  • Pip
  • Group: Members
  • Posts: 5
  • Joined: 2018-February-12

Posted 2018-February-12, 03:58

If it is 11/ 2 it is very easy to calculate but 10/3 is very tricky.
0

#3 User is offline   helene_t 

  • The Abbess
  • PipPipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 15,358
  • Joined: 2004-April-22
  • Gender:Female
  • Location:Hamilton, New Zealand

Posted 2018-February-12, 05:32

If you are missing three cards including the king, they can be distributed in 8 ways:
K43-void finesse wins
K4-3 finesse wins
K3-4 finesse wins
K - 34 both win
43 - K drop wins
4 - K3 nothing works
3 - K4 nothing works
void - K43 nothing works

So the finesse wins in 4/8 = 50% and the drop in 2/8 = 25%. In fact the drop is slightly better than this because a 2/1 split is a bit more likely than a 3-0 split so it's about 26%.
You might speculate on the psychopathology of some posters but hating them seems excessive --- Nige1
0

#4 User is offline   onaykk 

  • Pip
  • Group: Members
  • Posts: 5
  • Joined: 2018-February-12

Posted 2018-February-12, 06:24

2/1 split only changes the odds around %1? That was my main question maybe at least %10?
0

#5 User is offline   onaykk 

  • Pip
  • Group: Members
  • Posts: 5
  • Joined: 2018-February-12

Posted 2018-February-12, 06:27

But of course Finesse also wins in 1/2 in common at one of the positions so that also decreases. Thanks a lot.
0

#6 User is offline   NickRW 

  • PipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 1,918
  • Joined: 2008-April-30
  • Gender:Male
  • Location:Sussex, England

Posted 2018-February-12, 06:32

View Postonaykk, on 2018-February-12, 06:24, said:

2/1 split only changes the odds around %1? That was my main question maybe at least %10?


No, nothing like 10%.

2-1 split = 78%. 6 different distributions = about 13% for a specific case
3-0 split = 22%. 2 different distributions = about 11% for a specific case.
"Pass is your friend" - my brother in law - who likes to bid a lot.
1

#7 User is offline   pescetom 

  • PipPipPipPip
  • Group: Full Members
  • Posts: 116
  • Joined: 2014-February-18

Posted 2018-February-12, 08:00

View PostNickRW, on 2018-February-12, 06:32, said:

No, nothing like 10%.

2-1 split = 78%. 6 different distributions = about 13% for a specific case
3-0 split = 22%. 2 different distributions = about 11% for a specific case.


Surely those are the odds of finding the K on one specific side in the given case of distribution.
I think the OP was looking for the odds of success of the A drop versus finesse.

When there are 2 cards out then the A drop is 52% successful versus the finesse 50%.
When there are 3 cards out then the A drop is 25.7% successful versus the finess 50%.
So the drop is only about half as successful when there are 3 cards out instead of 2, and no longer makes sense.
0

#8 User is offline   gszes 

  • PipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 3,171
  • Joined: 2011-February-12

Posted 2018-February-12, 08:24

The relative success of a situation depends on thinking about all of the possible lie of the cards (not always easy to calculate) and to go with the play that seems to have the highest chance of success. Note how Helene_T list ALL of the possible lie of the opponents cards to come up with the solution that the finesse is best. One thing to add, do not forget the bidding when making your decision. Lets say you are in 6s (your side has around 28 hcp) and east has opened 1h. That means east is a monster favorite to hold the spade King and taking the finesse becomes a huge probable loser while playing for the drop at least gives you a reasonable chance at making.
0

#9 User is offline   onaykk 

  • Pip
  • Group: Members
  • Posts: 5
  • Joined: 2018-February-12

Posted 2018-February-12, 08:30

Thanks a lot
0

#10 User is offline   hrothgar 

  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 13,234
  • Joined: 2003-February-13
  • Gender:Male
  • Location:Natick, MA
  • Interests:Travel
    Cooking
    Brewing
    Hiking

Posted 2018-February-12, 08:32

I highly recommend a book titled "Bridge Odds for Practical Players"
Alderaan delenda est
0

#11 User is offline   pescetom 

  • PipPipPipPip
  • Group: Full Members
  • Posts: 116
  • Joined: 2014-February-18

Posted 2018-February-13, 07:36

View Posthrothgar, on 2018-February-12, 08:32, said:

I highly recommend a book titled "Bridge Odds for Practical Players"


On it's way across the ocean, thanks :D
Together with "Card Play Technique or the Art of Being Lucky".
0

Share this topic:


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