[gnasher]

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What do you think of the bidding so far, and what do you think should happen now?

[Fluffy]

I think that north's double of 5♠ is wrong. RHO commits to slam favourable, what is the point of double?, bidding 6♠ looks normal, or some lead directing fake bid like 6♣.

[mgoetze]

I think my double was bad and I should have bid 6♠ right away.

[mike777]

prefer 6s not x...then I guess to pass over 7h and let pard decide.

[han]

I think most of us have seen the hands, so what can we say about this?

Perhaps north would be better off bidding 6S instead of doubling. It is hard to imagine east going on to 7, and west doesn't have a spade control. The 6S bid would have made it a lot harder, and that's to be expected. Having bid 5S it won't be clear to west that partner's pass of 6S shows a first round control. The double helped them a lot, east could show the first round spade control.

In hindsight one could say that south might have bid 6D instead of 6S. It certainly would have made it easy for north. Should north have bid 7S anyway? Hard to say, it is a guess at that point. The diamond king might be a trick, or it might not be.

[Phil]

Maybe North could bid 6♦ instead?

As far as 'presenting' these problems, its very hard to show all four hands and say, "ATB" or "what do you think" and expect to get unbiased views on things. You'll get some ne'er-do-wells that go ahead and look up the hand and then post their brilliant, right answer but for the rest of us, I think its best to post it as a problem from the perspective of one of the challenging hands as a decision.

[lalldonn]

han, on 2012-April-23, 11:41, said:

In hindsight one could say that south might have bid 6D instead of 6S.

Or north instead of double or 6S

Despite it apparently not working out well, I think what everyone did was fine. There will always be multiple options on hands like this, from passing so they don't learn of your big fit, to doubling to suggest a save, to bidding a real or fake other-suit, to saving. It's easy to second guess yourselves.

[han]

6D by north? I'm going to classify that under the header "interesting thoughts".

If they bid on partner is on lead, and a diamond lead does look best at least against a small slam. Against a grand slam it is unlikely to matter what we lead. It's our only defensive asset, but it is only a 3-card suit. That's not what partner would expect, and he might well make the wrong decision.

They get two extra steps, but it isn't clear that it's going to help them much. Jlall's golden rule still applies though: the more room we give them, the more likely that they get it right. Also, knowing that we have the diamond king might help them a lot.

Still, it's definitely an interesting thought that probably wouldn't have occurred to me at the table.

[Fluffy]

IMO north's bids are lead directing, perhaps not at the 7 level, but anything else for me is. Change ♦K for ♦A and 6♦ is right.

[gszes]

I do not believe the N hand will be happy defending 6h or 7h.
That being the case at least N should bid 7s. Even if E is able
to pass and show the spade A their partner (who didnt know what
to do over 4s) will have to make a decision with precious little
extra information. Maybe we can preserve some of our ability
to sacrifice. I see little benefit to bidding just 6s (if we
go -6 it is only 1400 and is a save over 6h).

the 5s x left rho with the opportunity to not only show spade
control but show outside stuff as well. This extra space might
be all the opps need to bid 7n and poof goes our ability to
sacrifice.

[MrAce]

I would bid 6♠ with N hand

[gnasher]

I thought afterwards that I (South) should have bid 6♦ not 6♠, or else I should just save in 7♠ myself.

I tend not to sacrifice in situations like this, where we've made them guess. Here, though, it looks like they've guessed right. Partner has invited a sacrifice against 6♥, so he's unlikely to have a certain trick. It's not that likely that ♦Q is a winner, because they may throw diamonds on clubs, or ♦AK may be on the left, or one of them may have a doubleton. This is different from the one where Cherdano saved, because his queen was in a suit that he knew declarer would have to set up.

[JLOGIC]

gnasher, on 2012-April-24, 00:47, said:

I tend not to sacrifice in situations like this, where we've made them guess.

Very unsure about the wisdom of this when you are w/r and they bid a grand. This is especially true of guys who are not the types likely to bid grand just counting on you to save a lot. The math just seems bad and makes it a huge gamble to not be saving in these spots.

[gnasher]

JLOGIC, on 2012-April-25, 02:37, said:

Very unsure about the wisdom of this when you are w/r and they bid a grand. This is especially true of guys who are not the types likely to bid grand just counting on you to save a lot. The math just seems bad and makes it a huge gamble to not be saving in these spots.

I think you're overstating the IMP odds in favour of saving.

Suppose that 6♠ is going for 500, 7♠ goes for 800, and in the other room they reach the par contract. If we defend and we're wrong, we're -17. If we save and we're wrong, we're -7 instead of +12, for a swing of 19 IMPs. For the save to be right, we have to think they're odds-on to make.

That's when the save is fairly cheap. If you make the saves cost 800/1100, defending and being wrong costs 15, but the cost of a phantom save is 7 + 14 = 21, so the save is playing them to be 6:4 on.

This is why I should have bid 6♦. Our diamond fit both makes our sacrifice cheap and improves their grand slam chances, and we had the chance to find out about it.

[han]

gnasher, on 2012-April-25, 06:35, said:

Suppose that [snip] in the other room they reach the par contract.

Could you explain why this assumption is reasonable? After many calculations I wrote a long post and managed to thoroughly confuse myself, so I decided to delete it and just ask you why this is reasonable.

The one thing I did understand is that I can defend almost any bid very well by making the corresponding assumptions. I will have to remember that for future discussions with mikeh.

[han]

It seems to me that once you the other table bids to the par contract, you might as well assume that over 7S your opponents make the perfect guess as well. Then, bidding 7S is even less attractive because on some of the hands where 7H made 7NT will also make, and of course your opponents will only bid that when it makes and never when it doesn't. So you lose when sacrificing is wrong, but win only when sacrificing is right AND 7NT doesn't make.

Justin, on the other hand, should assume that the other table is in 6H. In practice that would also have been incorrect, as we were neither in 7NT nor 6H, but look at how these new assumptions change the odds:

If you bid 7S you always win 12 IMPs.

If you pass and 7H is down, you win 17 IMPs, so you gain 5 by passing. But if 7H is making then you lose 13 IMPs, so you lost 25 IMPs by passing. Now the odds are 5-1, so you should bid on when 7H has at least 17% chance of making.

I love it, I'm definitely going to use this kind of arguing more often.

[gnasher]

han, on 2012-April-25, 07:23, said:

Could you explain why this assumption is reasonable?

Because I wanted to justify my pusilanimity, of course.

I agree that if my teammates were allowed to play 6♥, that changes the odds greatly in favour of saving. But how likely is that when I think 6♠ is only -500, I'm trying to decide whether to save in 7♠, and one of my counterparts in the other room is world-class? If my opponents were weaker, I'd be more inclined to save, partly because of this factor, and also because saving is a much lower variance action than passing - if I save, our maximum absolute loss is 7IMPs.

It seems to me that all the other likely scenarios lead to similar conclusions as in my earlier post:
- If the contract at the other table was 7♠x or 7♥-1, my calculations still apply, I think.
- Suppose that I knew that teammates had defended 6♠x for 500. A phantom sacrifice would still cost 19. Failing to sacrifice when I should would turn -7 into -17, for a 10 IMP loss. There's still no great incentive to save.

[han]

gnasher, on 2012-April-25, 08:29, said:

- If the contract at the other table was 7♠x or 7♥-1, my calculations still apply, I think.

No they wouldn't. In both cases you need (a little) less than 50% to bid on.

Quote

- Suppose that I knew that teammates had defended 6♠x for 500. A phantom sacrifice would still cost 19. Failing to sacrifice when I should would turn -7 into -17, for a 10 IMP loss. There's still no great incentive to save.

Yes indeed, that would be the best argument for passing! You should assume the other table is in 6SX, Justin should assume that the other table is in 6H.

[gnasher]

han, on 2012-April-25, 09:34, said:

Yes indeed, that would be the best argument for passing! You should assume the other table is in 6SX, Justin should assume that the other table is in 6H.

So you let me down by bidding your cold grand slam?

[mgoetze]

I'm feeling left out, can I get more of the blame for this one?