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Textbook play problem - or is it? Three-part question

#1 User is offline   FrancesHinden 

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Posted 2009-March-16, 08:47

You misbid as shown, and end up in the wrong contract of 6. If only you had bid 5NT (choice of slams) rather than 6 you would be in the excellent spot of 6NT. But you didn't, and now you have to play it. You get the jack of clubs lead.

Scoring: IMP

P P 2NT P
3 P 3 P
3NT P 4 P
5 P 6 all pass


2NT = 20 to a bad 22
4 = trial bid i.e. length + we may still have a slam on if you have the right cards

Question 1
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There are (IMO) two sensible lines for the contract. What are they?

Question 2 (the difficult one)
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What is the best line?

(I did some sums and reckon there is about a 0.7% difference between the lines, once you have conditioned on the other things you need for either to work. But my sums may have gone wrong)

Question 3
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Suppose you start by cashing the king of hearts (which is certainly a viable line), and RHO plays an honour. Does that change your choice of line?
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#2 User is offline   gnasher 

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Posted 2009-March-16, 09:18

1. (a) Draw trumps, picking up LHO's Hxxx or QJ doubleton.

(b) Find RHO with Jxxx/9xxxx and three trumps, or Jx and two trumps. Cash two top trumps, followed by four rounds of diamonds (finessing against RHO if he hasn't already played the jack), as the hand with the trump winner follows. Throw dummy's last spade on the fifth diamond.

I can't see any point in posting a trump holding like this if neither of the options is a Devil's Coup, but I also can't see how to make it work.

2. I prefer the second line, because it's better in the sense of being more fun.

3. RHO should obviously falsecard with QJx, so no.

This post has been edited by gnasher: 2009-March-16, 09:20

... that would still not be conclusive proof, before someone wants to explain that to me as well as if I was a 5 year-old. - gwnn
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#3 User is offline   FrancesHinden 

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Posted 2009-March-16, 09:27

gnasher, on Mar 16 2009, 03:18 PM, said:


I think there's a third line. So perhaps the odds on the line you have thought of that I haven't are fairly close.

Quote

I can't see any point in posting a trump holding like this if neither of the options is a Devil's Coup, but I also can't see how to make it work.


Neither can I
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#4 User is offline   Phil 

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Posted 2009-March-16, 09:36

Agree with Gnasher's analysis.

By the way, I'm coming up with about 9% for Line I vs 11% for Line II (with a little help).

I also think you need to add in some singleton J's to the Line II calcs, although its interesting what West should do with J9 doubleton.
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#5 User is offline   rfedrick 

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Posted 2009-March-16, 09:58

I can only see the two obvious technical lines, so i'm probably missing something too.

But they are both sufficiently unlikely that i might be tempted for a defensive-error approach. Win the first club with the ace, cross to Q, play a heart to the 8. If LHO isn't looking at the spade Ace, you may get another club. After all, from LHO's point of view a spade could be a disaster from 10xx(x) if partner has Kxx(x) and declarer AQx(x). Yes, i'm sure he shouldn't get it wrong, but he might.

Alternatively - take two top hearts ending on table, and advance the J. If RHO has no reason to know his side have a trump trick he may duck smoothly from Axx(x). With one spade in the bag, you just need a mildly favourable diamond layout (3-3 is now good enough).

There are probably lots of others, that shouldn't work but might against middling-ability opponents.

The biggest downside is that it's embarrassing when the psychological approach fails but the technical line would have worked. Team-mates can be a humourless bunch.
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#6 User is offline   Hanoi5 

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Posted 2009-March-16, 13:00

Is the other line to play LHO for Hxx and xx? Diamonds should be played first, if LHO ruffs the third or fourth round trumps are drawn, if he refuses to ruff A and K are cashed before playing the final diamond to discard the last spade.

View Postwyman, on 2012-May-04, 09:48, said:

Also, he rates to not have a heart void when he leads the 3.


View Postrbforster, on 2012-May-20, 21:04, said:

Besides playing for fun, most people also like to play bridge to win


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#7 User is offline   FrancesHinden 

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Posted 2009-March-16, 16:15

Hanoi5, on Mar 16 2009, 07:00 PM, said:

Is the other line to play LHO for Hxx and xx? Diamonds should be played first, if LHO ruffs the third or fourth round trumps are drawn, if he refuses to ruff A and K are cashed before playing the final diamond to discard the last spade.

Yes, that's my third line. Of course life is slightly complicated because any decent defender won't ruff low... if he ruffs with an honour we need to over-ruff and then run the H10, so we need the heart honours split.

If he ruffs low, we over-ruff and cash the HK, and I assume we finesse on the way back if RHO plays an honour (there's no point now in the false card).

OK here are three lines. Which is best?

(My partner has disagreed with my percentage calculation, so don't trust that I'm right...)
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#8 User is offline   655321 

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Posted 2009-March-16, 17:22

If my numbers are correct, then drawing trumps is 9.0%.

Playing RHO for one of Jxxx diamond with any 3 trumps, Jx of diamonds with any 2 trumps, any 5 diamonds with any 3 trumps I make 10.6%.

The line of playing LHO for 2 small diamonds and Hxx trumps I make 3.8%. (although this number should be higher because we should add something more for LHO having Hx of trumps too)

Edit: I make the last line 7.1% when we give LHO 2 small diamonds along with either Hxx, Hx or xxx in trumps.

This post has been edited by 655321: 2009-March-16, 17:53

That's impossible. No one can give more than one hundred percent. By definition that is the most anyone can give.
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#9 User is offline   gnasher 

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Posted 2009-March-17, 02:52

If you set out upon the third line, but RHO played J on the second round, you should switch to my line (b). If RHO has played J from Jxxx and Hx, we're not gong to win this match anyway.

You'd also switch to (b) if either player played J on the first round.

I'm going to call this combination approach "line (d)".

(b) gains over (d) when:
- RHO has QJx and Jxxx
- RHO has three hearts and Jxxxx

(d) gains over (b) when:
- RHO has Hx and Jxxx and doesn't falsecard

That seems to make (d) rather better.

This post has been edited by gnasher: 2009-March-17, 02:58

... that would still not be conclusive proof, before someone wants to explain that to me as well as if I was a 5 year-old. - gwnn
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#10 User is offline   hatchett 

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Posted 2009-March-17, 04:23

I am probably going to regret getting involved in this since Gnasher is a rather better player than me but doesn't b also gain over d when LHO has QJ and Jx or any 5 card holding and also when RHO has QJ and xx or xxxx.

I think if are 3-3 you need no trump loser. Now b gains over d when RHO has QJ and d gains over b when RHO has H assuming you play trumps K and another
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#11 User is offline   FrancesHinden 

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Posted 2009-March-17, 04:45

Just a quick comment: five card diamond holdings onside aren't good enough, you need to be able to cash 5 diamond tricks, not 4.

Singleton jack on your left is the only 5-1 break that helps (and you will then lose to J9 doubleton if they think of it, which they won't).

Quote

The line of playing LHO for 2 small diamonds and Hxx trumps I make 3.8%. (although this number should be higher because we should add something more for LHO having Hx of trumps too)

Edit: I make the last line 7.1% when we give LHO 2 small diamonds along with either Hxx, Hx or xxx in trumps.


we might like to think a bit harder about what trump holdings we are picking up on our left.

LHO can relevantly have Hx (x6), Hxx (x6), HHx (x3), xxx (x1), Hxxx (x2). Assuming just that diamonds are 2-4, each of the 3 & 4 card holdings is 3.8% and each of the 2 card holdings is 3%. There are some other mild inferences which are too difficult to include e.g. LHO can't have the ace of spades and QJx of hearts.

LHO must ruff with an honour from Hxx or we can't go wrong, and must ruff low from xxx or Hxxx. I'm too stupid right now to work out LHO's correct play from the other holdings, and our correct consequential play.
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