[weejonnie]

So you get called to the table.

Declarer has played to the first trick (won by RHO) and then realises that RHO has led a card to trick 2 that he himself holds!

(Amazingly dummy did not hold any of the same cards as Declarer.)

Declarer then discovers that he has picked up the 13 cards from the slot on another board.

Now What!

(And what of the other (yet to be played) board (Declarer hasn't shown his other cards.))

The laws cover discovery during the auction period but not, as far as I am aware, obviously under the play period - unless you decide that the declarer has 13 missing cards from his hand. (In which case I suppose it is an unestablished revoke.)

[billw55]

weejonnie, on 2015-October-05, 09:40, said:

(Amazingly dummy did not hold any of the same cards as Declarer.)

By my figuring, the chance of this is about 1%. Strange things happen.

[barmar]

I'd rule that this makes normal play of the board impossible. Av- to the offending side, Av+ to the NOS, according to 12C2.

I think it also makes the board he took the cards from impossible to play, so same result there. Even though he hasn't shown his cards, his bidding presumably gave away lots of information about the hand.

[weejonnie]

billw55, on 2015-October-05, 09:59, said:

By my figuring, the chance of this is about 1%. Strange things happen.

Are you sure? I would have thought it was like the same birthday paradox. (Declarer's 1st card has 13 possible matches in dummy etc)

Which would give 1- (39/52)^13 = 97.624%

Another way of looking at it - declarer's 13 cards are in 4 hands - therefore there is 1 chance in 4 that a particular card is in dummy. - Thus you would expect 3 1/4 matches.

[billw55]

weejonnie, on 2015-October-05, 11:47, said:

Are you sure? I would have thought it was like the same birthday paradox. (Declarer's 1st card has 13 possible matches in dummy etc)

Which would give 1- (39/52)^13 = 97.624%

Another way of looking at it - declarer's 13 cards are in 4 hands - therefore there is 1 chance in 4 that a particular card is in dummy. - Thus you would expect 3 1/4 matches.

Well, our figures are fairly close: mine gives about a 98.7% chance of matching at least one card. So I think we must be in the ballpark. Still, we are a little off ... not sure who is correct, if either.

[Trinidad]

Maybe someone can run a sim.

Rik

[blackshoe]

barmar, on 2015-October-05, 10:07, said:

I'd rule that this makes normal play of the board impossible. Av- to the offending side, Av+ to the NOS, according to 12C2.

I think it also makes the board he took the cards from impossible to play, so same result there. Even though he hasn't shown his cards, his bidding presumably gave away lots of information about the hand.

Agree. 12A1, 12A2, 12C2, in both cases.

[WellSpyder]

billw55, on 2015-October-05, 12:14, said:

Well, our figures are fairly close: mine gives about a 98.7% chance of matching at least one card. So I think we must be in the ballpark. Still, we are a little off ... not sure who is correct, if either.

I think weejonnie's approach is only an approximation. It is true that there is a 13/52 chance that declarer's first card is in dummy. But if it isn't, there is a 13/51 chance that his next card is in dummy. And so on....

[RMB1]

WellSpyder, on 2015-October-06, 01:12, said:

I think weejonnie's approach is only an approximation. It is true that there is a 13/52 chance that declarer's first card is in dummy. But if it isn't, there is a 13/51 chance that his next card is in dummy. And so on....

It (obviously) doesn't matter what one hand is, so lets imagine that declarer 13 spades, then we need to know the chance of dummy has a spade void.

Any way, dummy's hand is a random hand dealt from the remaining 39 cards.

39C13 / 52C13 = 39/52 x 38/51 x ... x 27/40 = 1.28 %

[helene_t]

Actually if either opp had played one of declarer's cards to trick 1, we might argue that we could still treat it as taking place during the auction period since declarer hasn't revealed any of his cards yet.

The probability that none of those 15 cards are held by declarer is 0.56%.

BTW, why is normal play impossible? Maybe declarer actually had the card he played to trick 1. In that case, there is no problem with this board.

But the board from which declarer took his cards can't be played since everyone now knows how declarer bid his hand on the previous board.

[campboy]

weejonnie, on 2015-October-05, 09:40, said:

The laws cover discovery during the auction period but not, as far as I am aware, obviously under the play period - unless you decide that the declarer has 13 missing cards from his hand. (In which case I suppose it is an unestablished revoke.)

I think law 17D still applies, even though we are no longer in the auction period. The only thing that suggests otherwise is the heading for law 17 ("The Auction Period"), but according to the introduction headings do not limit the application of any law.

[barmar]

campboy, on 2015-October-06, 07:35, said:

I think law 17D still applies, even though we are no longer in the auction period. The only thing that suggests otherwise is the heading for law 17 ("The Auction Period"), but according to the introduction headings do not limit the application of any law.

Good point. And 17D2 says that we award an AAS if offender's partner has called after offender called with the wrong cards. That had to have happened in this case.

[pran]

campboy, on 2015-October-06, 07:35, said:

I think law 17D still applies, even though we are no longer in the auction period. The only thing that suggests otherwise is the heading for law 17 ("The Auction Period"), but according to the introduction headings do not limit the application of any law.

barmar, on 2015-October-06, 08:58, said:

Good point. And 17D2 says that we award an AAS if offender's partner has called after offender called with the wrong cards. That had to have happened in this case.

It does indeed. And note that unless either the board is passed out or the dealer made an opening bid which was followed by three passes, the last by the offender, the offender's LHO must have called after the offender's first call.

The error occurred during the auction period and there is nothing in Law 17 that limits its applicability only to errors discovered before the end of the auction period.

[barmar]

And 17D2 also says that we award an AAS if offender's replacement call differs from the cancelled call. In practice, this seems unlikely unless both calls were Pass or he repeats the original call even though it's now a psychic.

This is probably the rationale for awarding an AAS if offender's partner has called -- by that time, it's implausible that a regular bridge result can be obtained. So this is really a case of Law 12 being codified in a specific law.

[blackshoe]

An irregularity (pulling a hand from the wrong board) has occurred during the auction period (which starts for a side when either player of that side takes his hand from the board — Law 17A). In this case, as others have noted, we treat the irregularity as having occurred during the auction period because that's when it occurred. However, if an irregularity occurs after the opening lead is faced, the play period has irrevocably started (Law 41C) and it would be wrong to treat it as having occurred during the auction period, because it didn't.

This seems obvious. I think the confusion may arise because the irregularity wasn't discovered until the play period. But I think the law is about when it occurred, not when it was discovered.

[weejonnie]

WellSpyder, on 2015-October-06, 01:12, said:

I think weejonnie's approach is only an approximation. It is true that there is a 13/52 chance that declarer's first card is in dummy. But if it isn't, there is a 13/51 chance that his next card is in dummy. And so on....

Yes - I agree - couldn't be bothered to think it through.

[barmar]

blackshoe, on 2015-October-06, 10:02, said:

This seems obvious. I think the confusion may arise because the irregularity wasn't discovered until the play period. But I think the law is about when it occurred, not when it was discovered.

I think the other part of the confusion is that the rectification talks about cancelling the call and making a substitute call, but it doesn't seem like you can do this once the play period has started.

But since the other part of the rectification says that if offender's partner has called we cancel the whole board and award an AAS, that's not really relevant.