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Commonwealth Challenge Interesting Slam

#61 User is offline   lamford 

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Posted 2014-September-12, 17:05

View PostPhilKing, on 2014-September-09, 15:20, said:

There's quite a lot to be said for ducking the diamond.

I have come back to this now, and redone 24 hands with West always having exactly six diamonds. They are a different set of course, and ducking the diamond comes out way on top. Unbelievably, the contract was now makeable on all 24 hands, but only for sure by ducking the opening lead. If the defence continue diamonds, you can be forced to guess almost all the time. My revised estimate now is that both the spade finesse and endplay/squeeze line are around 40%, and ducking the lead is around 60% - you will play for East to have the king of spades and West to have the diamond guard, and play it as double squeeze. You will probably go off when West has spades and diamonds guarded and East hearts because you will play for East to have been squeezed. So, I must eat humble pie, and what I originally thought was the best line is probably the worst. It was rather better than the line chosen at the table. Of course, we need to multiply that 60% by the chance of West having exactly six diamonds. If that is under 67%, then running some clubs and falling back on the spade finesse is probably right again.
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#62 User is offline   PhantomSac 

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Posted 2014-September-12, 17:12

If you know the diamonds are 6-2 the other line goes up significantly. You make when LHO has 2 hearts or the SK or 3 small hearts without the QJT. Let's go back to this position:

AQ
x
xx
--

x
AK9
T

We play the AK of hearts. Now LHO must be down to 2 diamonds since we know the count so he pitches down to 1 major suit card and we throw a diamond. If he is down to a heart then if he had the SK he has pitched it. If not, we are down. But if he is down to a spade we are going to make it whether it is the king or not as if there are 2 spades out spades are 1-1, if there are 3 spades out there is only 1 heart out and we must assume RHO has it (else we cannot make) and we endplay righty.

Ofc if I knew diamonds were 6-2 I would duck the diamond for sure since I think 60 % is a wildly unrealistic estimate of the chances we would make it in that case in the real world.
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#63 User is offline   lamford 

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Posted 2014-September-12, 17:14

View PostMrAce, on 2014-September-12, 17:02, said:

You mean Gunnar Hallberg? He is a terrific player as I heard. But that shows he is only a human after all. Or perhaps V.G operator mistake.

I don't think Gunnar was the declarer. The hand is on Vugraph Archives as Scotland v England, Board 5:

2014-09-09 M2 2014 CNBC Glasgow RR5_13 Scotland
MURDOCH-SIME v
SMALL-KING

I tried to put a link up but that was too small (no pun intended). Gunnar is indeed a terrific player, but Small is very strong as well, and I did suspect a VG operator mistake, but the commentary suggests otherwise:

vugraphzft: minus one
paulg: Did Small miscount the hearts?
vugraphzft: There was an expletive
vugraphzft: I assume so

paulg: it was a pity because Small had played the hand very well to that point
vugraphzft: (South upset with self re last hand)
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#64 User is offline   lamford 

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Posted 2014-September-12, 17:17

View PostPhantomSac, on 2014-September-12, 17:12, said:

Ofc if I knew diamonds were 6-2 I would duck the diamond for sure since I think 60 % is a wildly unrealistic estimate of the chances we would make it in that case in the real world.

Do you think it is too low or too high? I would expect to make it more than that, as I will always make it when East has the king of spades but might well go off on the actual layout.
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#65 User is offline   lamford 

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Posted 2014-September-12, 17:20

View PostPhantomSac, on 2014-September-12, 17:12, said:

If you know the diamonds are 6-2 the other line goes up significantly. You make when LHO has 2 hearts or the SK or 3 small hearts without the QJT. Let's go back to this position:

True, but you also make it when diamonds are 6-2 when West has three hearts only, by ducking the opening lead. Always if you can read the ending. There is no layout that can hold the position.
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#66 User is offline   PhantomSac 

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Posted 2014-September-12, 17:22

It's way too low
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#67 User is offline   PhantomSac 

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Posted 2014-September-12, 17:32

View Postlamford, on 2014-September-12, 17:17, said:

Do you think it is too low or too high? I would expect to make it more than that, as I will always make it when East has the king of spades but might well go off on the actual layout.


For instance, how are you going to go off on this layout? Unless you play LHO to have 6 diamonds and 5 hearts you will make as they are forced to come down to Kx of spades and a diamond and thus only 2 hearts (if they come down to stiff king in spades even if you "misguess" you'll play the SA and the king will drop). It is when LHO has Kxxx of spades and pitches 2 spades and a heart that you might go down if you play him for 2461 instead.
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#68 User is offline   lamford 

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Posted 2014-September-12, 17:41

Yes I agree you will make much more than 60% of the time. But I am not sure how much more. Take this ending:

As I think you said, you will make when you cash the ace and king of hearts wherever the king of spades is. The only downside of this line is that if West can guard hearts and diamonds, you will go down, as you need to cash the ace of spades first in such lines; sometimes West will have three small hearts and you are cold again, or 10xx and not realise he should be guarding hearts. This line could be as high as 80% in practice. Of course, the defence can switch to a spade at trick two, which forces you to choose the double squeeze, and that appears to be best defence. I think you get to this ending:

Now as the cards lie, you need to cash the ace and king of hearts, but if you swap the spade honours you need to play a diamond to the ace. Given that the king of spades is around 4:3 on to be with East, you will probably go down. Can you see a way of improving on this plan, which I think is no more than 60%?

When I went through the 24 hands - which took me several hours - I formed a quick opinion on which lines worked. I agree I did that very poorly, but it would have taken me longer if I had analysed every line in detail. And I posted it because it is was - and still is - a very interesting hand.

And what do you think the chances of six diamonds compared with seven are?
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#69 User is offline   lamford 

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Posted 2014-September-12, 18:33

View PostPhantomSac, on 2014-September-12, 16:27, said:

But why do you now think that? You said in your 24 board simulation, ducking the diamond only made five times out of 24

Looking back, that was because the second round got ruffed 16 times! So, my setting West to have six+ diamonds was the wrong approach, and a blunder, as the dealing program gave him a seventh diamond too often. It is not that great a program in that it just deals out the remaining cards that have not been fixed. As I did not allow West to have eight diamonds, he got seven far too often. Mea culpa. The correct approach for me was to do two sets with the chance of six diamonds in the correct ratio to the chance of seven diamonds. My feel is that PhilKing is right, and West will have exactly six diamonds maybe 90% of the time. Firstly he is more likely to have six than seven, and secondly he might bid 4D with seven, so a big parlay. I now confirm that I think the best line is to duck the diamond, second best to run the clubs and try to judge the endplay falling back on the spade finesse if it looks like the endplay will not work, and the third choice to take a spade finesse. What do I think are the true odds? I would estimate: Duck 63% (maybe 90% x 70%). Win and run trumps but be ready to fall back on spade finesse 50%. Draw trumps and take the spade finesse 40%
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#70 User is offline   lamford 

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Posted 2014-September-12, 18:46

View PostPhantomSac, on 2014-September-12, 17:32, said:

For instance, how are you going to go off on this layout?

So, if you duck the opening lead, and win the spade switch, what ending are you going to choose?
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#71 User is offline   PhilKing 

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Posted 2014-September-12, 19:07

View Postlamford, on 2014-September-12, 16:04, said:

No, because you can go off on lines with the king of spades right by attempting the endplay on East.


I don't really get this - I thought THE PHANTOM had pretty much been established that this was not the case.

If the spade is onside, I thought you could only go off if someone had fourteen cards. I now think winning trick 1 is right because this is one of those weird compound thingies that works best without the count.
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#72 User is offline   PhantomSac 

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Posted 2014-September-12, 19:18

I was analyzing if they continued diamonds.

If they switch to a spade it looks like we have to guess what squeeze to take in this position:

Q
x
Ax
--

--
AK9
x
--

That is no good. If we had the jack of clubs that probably wouldn't be a big deal since on a spade shift we could ruff a spade, CK, CA, spade ruff pull trumps and again go down when LHO had Kxxx of spades (unless we made an inspired guess) but make otherwise. But if we have to play the CK first we lose to Jxxx of clubs onside now which seems like a big deal.

Seems like a spade shift is best after all? I should not have trusted PhilKing :P But maybe I'm missing something obvious. Maybe 4-0 clubs onside isn't such a big deal with diamonds 6-2 also, dunno. But again, if we know diamonds are 6-2 the squeeze line becomes much better as we will know the count and can accurately strip squeeze righty if lefty has only 2 hearts or xxx, so maybe that is best. It's probably close since if they don't shift to a spade we are in great shape and if they do we're still in pretty decent shape.
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#73 User is offline   PhantomSac 

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Posted 2014-September-12, 19:22

Phil are we wrong that you can't just claim on the spade shift, LHO might guard spades/diamonds or RHO might guard hearts/spades and in this case we actually won't be able to tell by their discards since they will basically be forced.

I think trying to isolate the spade menace is correct in that case, and had a very PhilKing-like thought that if they do shift to a spade and we ruff a spade maybe we should just play club to the ace and ruff a spade with the ten, risking Jx of clubs and 2 spades on our left in order to gain on 4-0 clubs onside (we will still have to guess which sqz in the end to play for). It would be the ultimate PhilKing line, risk going down on a diamond ruff and also on a spade overruff in order to have a near claim in the endgame and protect against 4-0 trumps :P

Edit: Also sry you lost in the semis, is there a bronze playoff?
Edited multiple times!

This post has been edited by PhantomSac: 2014-September-12, 19:26

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#74 User is offline   lamford 

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Posted 2014-September-12, 19:31

View PostPhilKing, on 2014-September-12, 19:07, said:

I don't really get this - I thought THE PHANTOM had pretty much been established that this was not the case.

If the spade is onside, I thought you could only go off if someone had fourteen cards. I now think winning trick 1 is right because this is one of those weird compound thingies that works best without the count.

That was quite a few hours ago, and we have since agreed that, provided you reverted to the spade finesse when the endplay might not work, you would always make it when the spade was right. That prevents you making it quite a lot of the time when the king of spades is wrong, however. The downside of winning the diamond is when the diamonds are 6-2 and West has three hearts, when you have to duck, when you are 100% if you can see the opponents' cards. West will have three hearts over half the time, as his most likely shapes are 3-3-6-1, 2-3-6-2 and 3-2-6-2. I think the compound squeeze may indeed work better without the count in theory, provided you can read the ending, but the payoff to three hearts is too great.
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#75 User is offline   lamford 

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Posted 2014-September-12, 19:43

View PostPhantomSac, on 2014-September-12, 19:22, said:

I think trying to isolate the spade menace is correct in that case, and had a very PhilKing-like thought that if they do shift to a spade and we ruff a spade maybe we should just play club to the ace and ruff a spade with the ten, risking Jx of clubs and 2 spades on our left in order to gain on 4-0 clubs onside (we will still have to guess which sqz in the end to play for).

I like this line a lot. We will guess to play the double squeeze still with East having the spade guard, and West the diamond guard, but now we pick up Kxx with West, the actual layout. Brilliant idea and a great post.

One slight improvement. Is it better, after ruffing a spade, to play the king and ace of clubs before ruffing another spade? That loses on 4-0 trumps but gains when West is 2-3-6-2 with the jack of clubs, as we still have the double squeeze.

For what it is worth, I did 24 more hands, assuming diamonds are 6-2, and in 22 of them your new line worked. We have to discount that for diamonds 7-1, of course, but even so I think we are in to 85% territory.

This post has been edited by lamford: 2014-September-13, 03:56

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#76 User is offline   paulg 

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Posted 2014-September-13, 01:52

View PostPhantomSac, on 2014-September-12, 19:22, said:

Edit: Also sry you lost in the semis, is there a bronze playoff?

This is a strange event where each country has one team that is eligible for a medal but can enter multiple teams, together with a handful of sponsored teams. There were only three medal-eligible teams in the semi-finals so PhilKing was guaranteed a medal of some colour and he will play India today to decide the silver and bronze medals.

Meanwhile Wales will play the Chairman's Team in the final, guaranteed to get the Gold medal but not guaranteed to win the event.
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#77 User is offline   lamford 

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Posted 2014-September-13, 03:40

View Postpaulg, on 2014-September-13, 01:52, said:

This is a strange event where each country has one team that is eligible for a medal but can enter multiple teams, together with a handful of sponsored teams.

There are events within events in the chess world too. For example this year's Scottish and Commonwealth Chess Championship.

I think I am learning a little more about this hand as we go on. I still think that it is right to duck the first diamond (by quite some margin), but then
a) If West has three or more hearts and no king of spades, he should continue diamonds
b) If West has king to four spades he should switch to spades.

In both cases, declarer is still cold but may play the wrong squeeze.

And I think this comment on vugraph was wrong:
"paulg: it was a pity because Small had played the hand very well to that point".

Declarer had not ducked the opening lead, had discarded the diamond threat from dummy prematurely, and had then tried an endplay which required a misdefence, as, by then, he knew West had started with three hearts and diamonds were 6-2, so he should now have taken the spade finesse, as PhantomSac correctly points out. Nearly as bad as some of my analysis on this thread.
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#78 User is offline   paulg 

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Posted 2014-September-13, 07:26

View Postlamford, on 2014-September-13, 03:40, said:

And I think this comment on vugraph was wrong:
"paulg: it was a pity because Small had played the hand very well to that point".

Declarer had not ducked the opening lead, had discarded the diamond threat from dummy prematurely, and had then tried an endplay which required a misdefence, as, by then, he knew West had started with three hearts and diamonds were 6-2, so he should now have taken the spade finesse, as PhantomSac correctly points out. Nearly as bad as some of my analysis on this thread.

If only I could do the analysis of a four-page thread, ignoring the fact that I can see that a simple spade finesse works, in the few seconds that I have while responding to all the kibs asking why is he not taking the finesse. :)

I still think he played it well up to the point he tried the endplay.
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#79 User is offline   lamford 

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Posted 2014-September-13, 10:07

View Postpaulg, on 2014-September-13, 07:26, said:

If only I could do the analysis of a four-page thread, ignoring the fact that I can see that a simple spade finesse works, in the few seconds that I have while responding to all the kibs asking why is he not taking the finesse. :)

I still think he played it well up to the point he tried the endplay.

My apologies. I mistakenly thought that all BBO commentators had Deep Finesse, Bridge Dealer, Bridge Analyser, Hawkeye, Snickometer and goal-line technology at their fingertips.
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#80 User is offline   PhilKing 

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Posted 2014-September-15, 09:58

View PostPhantomSac, on 2014-September-12, 19:22, said:

ame and protect against 4-0 trumps :P

Edit: Also sry you lost in the semis, is there a bronze playoff?
Edited multiple times!


There was a silver medal play off. We won that, but never got a crack at Wales.

Basically, if you are English you have to beat the Hacketts in the semis in order to have a chance of gold even the their team was not eligible for a medal. I guess it's a bit like being USA 2. B-)
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