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Interesting play problem

#1 User is offline   lamford 

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Posted 2018-June-01, 15:35


You tell the opponents that your partner's 2NT did not promise a 4-card major. West leads the four of hearts (fourth), and you play low in dummy and win East's nine with the ten. You decide to cross to the king of diamonds and West plays the five, East the six. They play reverse Smith by both sides (low continue) and are experts, in the London Super League, so East is certainly up to to flying with the king of spades if necessary. Your plan?
I prefer to give the lawmakers credit for stating things for a reason - barmar
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#2 User is offline   cherdano 

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Posted 2018-June-02, 10:15

AJ84 is such an unattractive lead, especially on this auction, that I'll play West for 5 hearts - seems also a little bit more likely to make sense of the diamond spots. So I'll play for three club tricks, with the triple finesse - run the 9.
The easiest way to count losers is to line up the people who talk about loser count, and count them. -Kieran Dyke
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#3 User is offline   lamford 

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Posted 2018-June-02, 16:53

View Postcherdano, on 2018-June-02, 10:15, said:

AJ84 is such an unattractive lead, especially on this auction, that I'll play West for 5 hearts - seems also a little bit more likely to make sense of the diamond spots. So I'll play for three club tricks, with the triple finesse - run the 9.

If the nine is not covered, do you rise or run it?
I prefer to give the lawmakers credit for stating things for a reason - barmar
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#4 User is offline   cherdano 

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Posted 2018-June-05, 05:56

View Postlamford, on 2018-June-02, 16:53, said:

If the nine is not covered, do you rise or run it?

As I said, I would run it. This seems the percentage line in isolation, and I don't see how it would get worse in context. Am I missing something?
The easiest way to count losers is to line up the people who talk about loser count, and count them. -Kieran Dyke
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#5 User is offline   lamford 

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Posted 2018-June-05, 10:05

View Postcherdano, on 2018-June-05, 05:56, said:

As I said, I would run it. This seems the percentage line in isolation, and I don't see how it would get worse in context. Am I missing something?

I am not sure. This loses to singleton T, J or Q (as you will surely cash a top one on round 2) and gains on 52, 54 and 42 offside, so seems to be a small gain. However, with QJT5 and QJT4, East, who cannot see the eight or six, may cover much of the time; I don't think he covers from QJT2. I did run it but thought it was very close. All lines led to Rome as clubs were 3-3, and hearts were indeed 5-2.
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#6 User is offline   cherdano 

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Posted 2018-June-05, 10:31

View Postlamford, on 2018-June-05, 10:05, said:

I am not sure. This loses to singleton T, J or Q (as you will surely cash a top one on round 2) and gains on 52, 54 and 42 offside, so seems to be a small gain. However, with QJT5 and QJT4, East, who cannot see the eight or six, may cover much of the time; I don't think he covers from QJT2. I did run it but thought it was very close. All lines led to Rome as clubs were 3-3, and hearts were indeed 5-2.

No, I was planning to repeat the finesse. This picks up three club tricks whenever RHO has more club honours than LHO, which is 50% in isolation. Given that LHO has lead a 5-card suit, the actual odds should be a little better than that.
Even if you assume that RHO always splits with QJTx, my line almost breaks even with leading the 9 to a top honour:
- loses if LHO has HH or HHx
- wins when LHO has H or Hx
(It's infinitesimally superior if you naively use vacant spaces on the assumption that hearts are 5=2; probably slightly inferior if you were to properly take into account the lead implication; and probably considerably better if you assume that RHO sometimes ducks from QJTx.)
Did I miss something?
The easiest way to count losers is to line up the people who talk about loser count, and count them. -Kieran Dyke
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#7 User is offline   lamford 

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Posted 2018-June-07, 02:21

View Postcherdano, on 2018-June-05, 10:31, said:

No, I was planning to repeat the finesse. This picks up three club tricks whenever RHO has more club honours than LHO, which is 50% in isolation. Given that LHO has lead a 5-card suit, the actual odds should be a little better than that.
Even if you assume that RHO always splits with QJTx, my line almost breaks even with leading the 9 to a top honour:
- loses if LHO has HH or HHx
- wins when LHO has H or Hx
(It's infinitesimally superior if you naively use vacant spaces on the assumption that hearts are 5=2; probably slightly inferior if you were to properly take into account the lead implication; and probably considerably better if you assume that RHO sometimes ducks from QJTx.)
Did I miss something?

OK. My plan was to run the nine as well, but then cash a top club on the second round. I succeed when West has xx, QJ, QT, JT and on all 3-3 breaks, without adjusting for hearts 5-2 that is around 6/15*24% + 36% or about 46%. I think adjusting for hearts 5-2 pushes that up to around 50%. Your line succeeds with any layout with two honours onside, so a bit more than 50%, given that any specific club is about 11/8 on to be onside so I think your line is better. On the actual hand there was HHx offside, so your line would have gone down, and I think now so should I have done.

Actually, I am again not so sure, as when the first club has lost, West can have HHH, HHx, Hx or Hxx but cannot have xxx or xx or x, so he is more likely to have two honours as he does not have none. It is a bit like sampling red and blue socks where you do not know how many pairs of each are in a draw and you draw out a blue sock ...
I prefer to give the lawmakers credit for stating things for a reason - barmar
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