[pilowsky]

Here's something that everybody knows (L. Cohen)

My lack of knowledge struck again for 0%.
What should South do? Why?

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[smerriman]

I definitely wouldn't double, if that's what you mean. It asks for a spade lead, but it looks like partner is broke and you have no expectation of taking 5 tricks even with a spade lead.

[spade7]

Pass

[P_Marlowe]

 smerriman, on 2021-October-15, 01:45, said:

I definitely wouldn't double, if that's what you mean. It asks for a spade lead, but it looks like partner is broke and you have no expectation of taking 5 tricks even with a spade lead.

If he has the ten of spades, you most likely have 5 tricks.
But I would not double either.

[Cyberyeti]

 P_Marlowe, on 2021-October-15, 03:27, said:

If he has the ten of spades, you most likely have 5 tricks.
But I would not double either.

Well you do, but he has to have precisely 10x, if he has 10xx he might not lead the 10.

[nige1]

pilowsky ' here's something that everybody knows (L. Cohen)
My lack of knowledge struck again for 0%.
What should South do? Why?
+++++++++++++++++++
IMO L Cohen and Pilowsky are right
Double for a ♠ lead
Your best hope of defeating the contract.

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 P_Marlowe, on 2021-October-15, 03:27, said:

If he has the ten of spades, you most likely have 5 tricks.But I would not double either.

 Cyberyeti, on 2021-October-15, 03:34, said:

Well you do, but he has to have precisely 10x, if he has 10xx he might not lead the 10.

A useful convention is that when partner doubles for a lead, then lead high.
Another argument for doubling.

[LBengtsson]

X for ♠ lead. I know also 3NT may make but if partner leads any suit other than ♠ it will probably give a tempo to declarer. How do we know partner has nothing? East/West could be push bidding 3NT vulnerable game with 23 count. I will X anyone other than Meckwell. Would even X Meckwell if I felt my Dala horse was winking at me lol!

[AL78]

 Cyberyeti, on 2021-October-15, 03:34, said:

Well you do, but he has to have precisely 10x, if he has 10xx he might not lead the 10.

There is another small chance, declarer holds QT doubleton and the 1♠ was bid on 5 rag.

I can see the merit in doubling if that asks for a spade lead. If partner holds the ten from two or three and leads it, we have guided partner to the killing lead. If the layout is such that declarer is always making, it might be a bad score, but it was never going to be more than an average, and sometimes you have to try and generate something your way.

[mycroft]

now High Level Pro, from 20 years ago said:

"lead a spade", or "-750"

Absolutely the only chance to set the contract. Absolutely conceding a zero rather than A- when it's the right lead, holding them to 9 tricks. Your guess.

[mikeh]

Match points or imps/rubber?

At mps, there is too much risk, imo, the double getting the hoped for spade lead and finding that you’ve saved the overtrick.

-750 isn’t even a moral victory against -630

At imps or rubber, the double seems far more attractive since it is very likely our only chance to beat this.

+200 v -600/630 is huge…far more than -750 v -630.

Of course, they might send it back and/or make a doubled overtrick.

Say I was dummy, and held Q1098x Kx QJx AJx that double would be sent back at the speed of light, since you have nowhere to run and I know you’re not going to like my spade holding. Opener will have x AJ10xx Kxx KQxx

But scared bridge is rarely winning bridge.

[cherdano]

We have the S9 Mike - makes redouble less likely?
Otherwise agree with everything you said. (Ok, the overtrick does not seem likely to me, would require them to have missed a 9 card spade fit or me to misguess on defence. )

[nige1]

 LBengtsson, on 2021-October-15, 05:41, said:

X for ♠ lead. I know also 3NT may make but if partner leads any suit other than ♠ it will probably give a tempo to declarer. How do we know partner has nothing? East/West could be push bidding 3NT vulnerable game with 23 count. I will X anyone other than Meckwell. Would even X Meckwell if I felt my Dala horse was winking at me lol!

South's ♠9 is enough to justify the wink by LBengtsson's Dala Horse. The main motive for Lightner and other lead-directing doubles is not bigger penalties; but rather, to defeat contracts that might otherwise succeed. That tilts the odds in their favour. Here. for example, 3NX might make but taking advantage of the unfavourable lie of the cards could result in a several-trick defeat, making a good score more likely, whatever the scoring method. Skid Simon lauded the merits of Lightner doubles

S J Simon said:

one of the most brilliant contributions to Contract Bridge yet made.

[johnu]

Funny, I had a somewhat similar hand earlier this year and made a speculative double. Turns out we couldn't beat 3NT, but we were playing good opponents and they decided to run. Obviously they overestimated the soundness of my doubles.

[mikeh]

 cherdano, on 2021-October-15, 14:13, said:

We have the S9 Mike - makes redouble less likely?
Otherwise agree with everything you said. (Ok, the overtrick does not seem likely to me, would require them to have missed a 9 card spade fit or me to misguess on defence. )

I think Q10xxx would be enough…heck, Q10xx is an assured stopper after the double…north won’t have an entry very often.

It’s odds on that dummy has 5 spades, since he used FSF after 2C. Not guaranteed…he might have been looking for a club or heart rebid…say Q10xx Kx QJx AJxx..obviously I’m hoping for no spade 10 in dummy…and partner finding the lead.

Side note: with one partner I play the Meckwell doubt showing redouble. If dummy lacks a sure stopper he can redouble, if the gadget’s available.

[pilowsky]

Tragically, I was suffering from a severe bout of anosognosia.
I suppose this means that you don't know what you don't know even when everyone does.
I certainly got a learning experience from P. for not knowing this.

So, not only did I not 'gno', but I (North) brutally set about discarding spades right up until the end.
A slightly unusual feature of this hand is that only one lead allows the contract to make.

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[johnu]

 pilowsky, on 2021-October-15, 17:33, said:

So, not only did I not 'gno', but I (North) brutally set about discarding spades right up until the end.

Good job keeping the 5th round of diamonds. There's a reason that Diamonds are Forever was the title of a Bond book and film. Keep your diamonds and they will be as good as gold.

[akwoo]

In this case, it's not just a matter of convention that the double requests a spade lead.

Partner has something like an opening hand for doubling 3N, but they did not make a takeout double or overcall of 1S when they had the chance.

Let's assume South has an opening hand that doesn't particularly want a spade lead. That might look something like ♠Kxx ♥Qxx ♦Kx ♣AJxxx

I don't know about you, but I'm doubling 1S with that hand.

[mikeh]

 akwoo, on 2021-October-15, 20:33, said:

In this case, it's not just a matter of convention that the double requests a spade lead.

Partner has something like an opening hand for doubling 3N, but they did not make a takeout double or overcall of 1S when they had the chance.

Let's assume South has an opening hand that doesn't particularly want a spade lead. That might look something like ♠Kxx ♥Qxx ♦Kx ♣AJxxx

I don't know about you, but I'm doubling 1S with that hand.

After (1H) P (1S) doubling with your example hand would not be chosen by any good player…it’s a takeout double showing the minors.

[mikl_plkcc]

Why does a double asking for a ♠ here?

[mycroft]

Some pairs just agree that it does (or does when other rules do not apply).

But the traditional meaning of double of 3NT by the non-leader is "lead dummy's first bid suit, it goes down if you do, and you'd never find the lead normally." Here, spades.

The idea is that, like doubles of slams, you're never getting rich on voluntarily bid 3NT contracts, and gambling 150 (if you're wrong) vs 50 or 100 (if you're right) is a bad gamble, especially when you're giving away the hand to declarer. Sure, it might be +300 or +500 instead of +100 or +200, but it could also be -650 or -950 instead of -430 or -630 (or, again, -5/750 vs +50/100 if they wouldn't have made it if you were quiet).

So it should be used as a "do something unusual" beacon instead, because now you're gambling 150 if you're wrong into 500 or 800 (-400 becomes +100, -600 becomes +200) if you're right, and the only thing you're giving away is information declarer is going to figure out pretty quickly anyway, and she likely won't be able to use.

Having said that, not sure I'd do it on this hand, as partner rates to have nothing, and I don't in fact have 5 tricks if I get a spade through. It's only because 4SF (or 4SNat, but choose to raise to game) on a misfitting boring 11 means that opening leader does in fact have a trick/entry that this one works.