BBO Discussion Forums: Revoke question - BBO Discussion Forums

Jump to content

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

Revoke question EBU

#1 User is offline   VixTD 

  • PipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 1,052
  • Joined: 2009-September-09

Posted 2016-January-25, 12:15

A friend described a situation from a recent game which I have reproduced as best I can as follows:

............... -
............... -
............... A6
...............98
... -................... -
... -...................-
... 10................ Q52
...432................... 7
............... 109
............... -
............... J
...............10

South is declarer in a spade contract. He leads A from dummy and discards 10. He then leads 6 and wins with the jack, as East didn't see any point in playing the queen.

(1) When the revoke is ruled on at the end of play, how many of the last four tricks should the defence be awarded?

(2) If we add an extra card to each hand as follows, with the same play (A discarding a club, diamond ducked by East), how many of the last five tricks now?

............... -
............... -
............... A6
...............985
... -................... -
... -...................-
... 103................ Q52
...432................... 76
............... 109
............... -
............... J4
...............10

(3) Finally if the 10 and 2 were swapped between South and West in the last diagram, how many?
1

#2 User is offline   RMB1 

  • PipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 1,841
  • Joined: 2007-January-18
  • Gender:Male
  • Location:Exeter, UK
  • Interests:EBU/EBL TD
    Bridge, Cinema, Theatre, Food,
    [Walking - not so much]

Posted 2016-January-25, 12:36

The revoke does not win the trick (in the hand that revoked), and declarer does win tricks, so the penalty is one trick.

In case (1) declarer makes the rest; equity, at the point A is played, is no tricks to the defence; so the defence get one trick (from the penalty).

In case (2) declarer loses one trick (4); equity, at the point A is played, is one trick to the defence; so the defence get two tricks (table result and the penalty)

In case (3) declarer loses one trick (4); equity, at the point A is played, is two tricks to the defence (Q, 10); so the defence get two tricks (table result and the penalty; Law 64C would give them the same two tricks)

What am I missing? (I don't think East is entitled to Q and the revoke penalty. Equally I don't think equity involves East ducking the second diamond when declarer hasn't revoked.)
Robin

"Robin Barker is a mathematician. ... All highly skilled in their respective fields and clearly accomplished bridge players."
0

#3 User is offline   VixTD 

  • PipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 1,052
  • Joined: 2009-September-09

Posted 2016-January-25, 13:05

View PostRMB1, on 2016-January-25, 12:36, said:

What am I missing?

As I understand it from my correspondent, East was after "equity tricks" on top of "penalty tricks" (after the manner of defenders in these situations). There was also a question of whether East should have played the queen on the second round of diamonds anyway, on the grounds that it cannot cost (but I am not of this opinion).

One interesting point I thought of in the first scenario was whether South realised 10 was a winner. After all, he did try to throw it away. Might he still discard the club if East played Q on the second round, choosing to lose a diamond trick now rather than a club trick later?
0

#4 User is offline   barmar 

  • PipPipPipPipPipPipPipPipPipPipPipPip
  • Group: Admin
  • Posts: 21,594
  • Joined: 2004-August-21
  • Gender:Male

Posted 2016-January-25, 13:08

The defense doesn't get equity plus the revoke penalty. They get the revoke penalty as long as this is at least enough to restore equity. If it's not, they get equity.

So in cases (1) and (2) we transfer 1 trick to the defense. In case (1) this is more than equity, in case (2) it's just equity.

In case (3), equity is 2 tricks to the defense, which is more than the revoke penalty, so we assign that.

#5 User is offline   barmar 

  • PipPipPipPipPipPipPipPipPipPipPipPip
  • Group: Admin
  • Posts: 21,594
  • Joined: 2004-August-21
  • Gender:Male

Posted 2016-January-25, 13:11

View PostVixTD, on 2016-January-25, 13:05, said:

One interesting point I thought of in the first scenario was whether South realised 10 was a winner. After all, he did try to throw it away. Might he still discard the club if East played Q on the second round, choosing to lose a diamond trick now rather than a club trick later?

When you're down to all winners, you have to pitch winners on other winners. So it's not clear that he thought he was pitching a loser.

#6 User is offline   VixTD 

  • PipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 1,052
  • Joined: 2009-September-09

Posted 2016-January-26, 07:41

View Postbarmar, on 2016-January-25, 13:11, said:

When you're down to all winners, you have to pitch winners on other winners. So it's not clear that he thought he was pitching a loser.

The situation that occurred was described to me without the cards being given, so I made up a layout, and amended it when I was told it wasn't quite right. I didn't quite get the effect I wanted.

If South has missed the J in his hand it seems sensible to throw the club, but I just wondered how the TD should go about deciding doubtful cases when trying to reconstruct what would have happened without the revoke. It doesn't make any difference to the outcome here, as the defence's expectation without the revoke is either no tricks if declarer realises the club is high, or one trick if he doesn't, so there's no further equity adjustment in either case after they get their penalty trick.
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 2016-January-26, 16:52

View PostVixTD, on 2016-January-25, 12:15, said:

A friend described a situation from a recent game which I have reproduced as best I can as follows: South is declarer in a spade contract. He leads A from dummy and discards 10. He then leads 6 and wins with the jack, as East didn't see any point in playing the queen.
When the revoke is ruled on at the end of play, how many of the last four tricks should the defence be awarded?
If we add an extra card to each hand as follows, with the same play (A discarding a club, diamond ducked by East), how many of the last five tricks now?
Finally if the 10 and 2 were swapped between South and West in the last diagram, how many?
IMO, The director might ask South more questions. For example: did South know the s were winners? After questioning, the director might judge that declarer thought the s were losers and after he'd revoked in s, he could have known that East would fail to rise with Q, believing that his partner held the J. If he so judges, the director might rule 2 tricks to defenders.

IMO, the old 2-trick revoke rule was fairer and simpler; also easier to understand and apply. In common cases like this, the new rule is incomprehensible and controversial. It seems that it sometimes allows a player to revoke with impunity. If nobody notices, then he gains. If he's found out, then he forfeits just the one trick that he would have lost anyway.. Unfortunately, "Equity" law rewards infraction, in this kind of way. This can send the wrong message to players. It's no surprise that top professionals can rationalize their drift into cheating :(
0

#8 User is offline   Vampyr 

  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 10,611
  • Joined: 2009-September-15
  • Gender:Female
  • Location:London

Posted 2016-January-26, 18:02

Yes the current revoke law has no deterrent effect.
I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones -- Albert Einstein
0

#9 User is offline   gordontd 

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

Posted 2016-January-27, 02:17

View PostVampyr, on 2016-January-26, 18:02, said:

Yes the current revoke law has no deterrent effect.

I doubt it would seem that way to someone who has revoked with the ace of trumps against a grand slam.
Gordon Rainsford
London UK
0

#10 User is offline   Vampyr 

  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 10,611
  • Joined: 2009-September-15
  • Gender:Female
  • Location:London

Posted 2016-January-27, 05:22

View Postgordontd, on 2016-January-27, 02:17, said:

I doubt it would seem that way to someone who has revoked with the ace of trumps against a grand slam.


Can there be such a thing as a deterrent which happens after the fact?
I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones -- Albert Einstein
0

#11 User is offline   gordontd 

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

Posted 2016-January-27, 05:45

View PostVampyr, on 2016-January-27, 05:22, said:

Can there be such a thing as a deterrent which happens after the fact?

Wouldn't it deter you from doing it again? Or the knowledge that this would be the outcome deter you from doing it in the first place?
Gordon Rainsford
London UK
0

#12 User is offline   Vampyr 

  • PipPipPipPipPipPipPipPipPipPip
  • Group: Advanced Members
  • Posts: 10,611
  • Joined: 2009-September-15
  • Gender:Female
  • Location:London

Posted 2016-January-27, 06:12

View Postgordontd, on 2016-January-27, 05:45, said:

Wouldn't it deter you from doing it again? Or the knowledge that this would be the outcome deter you from doing it in the first place?


OK, maybe there is some sort of deterrent effect on a vanishingly small percentage of people.
I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones -- Albert Einstein
0

#13 User is offline   gordontd 

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

Posted 2016-January-27, 06:42

View PostVampyr, on 2016-January-27, 06:12, said:

OK, maybe there is some sort of deterrent effect on a vanishingly small percentage of people.

Clearly it's so small that a large number of players are going around deliberately revoking and getting away with it.
Gordon Rainsford
London UK
0

#14 User is offline   Lanor Fow 

  • PipPipPipPip
  • Group: Full Members
  • Posts: 191
  • Joined: 2007-May-19

Posted 2016-January-27, 07:30

I revoked against a small slam with two natural trump tricks by ruffing with one of them, (partner coming up with a third trick) for a 17 imp and 12(ish) vp swing at Brighton about 8 or so years ago. This has certainly stuck with me to this day, and may have made me more careful (I don't think, however, that I habitually revoked before)
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