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More Strong NT judgement

#1 User is offline   lamford 

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Posted 2019-March-14, 05:53


Partner opens 1NT, 15-17. You can transfer to clubs with 2S and bid minorwood for clubs or you can bid 4S (Gerber). If you elect to bid 6NT, what percentage of the time would you expect this to make, double dummy, with both the defenders and declarer looking through the back of the cards?
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#2 User is offline   etha 

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Posted 2019-March-14, 06:44

how about we transfer to clubs and bid 3! assuming that shows a singleton. I can try to do the sim of 6NT.
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#3 User is offline   lamford 

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Posted 2019-March-14, 06:50

View Postetha, on 2019-March-14, 06:44, said:

how about we transfer to clubs and bid 3! assuming that shows a singleton. I can try to do the sim of 6NT.

If it does show a singleton, they may double to show the ace and that may backfire. Yes transfer and jump would be self-splinter.
I prefer to give the lawmakers credit for stating things for a reason. - barmar
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#4 User is offline   hrothgar 

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Posted 2019-March-14, 06:52

View Postlamford, on 2019-March-14, 05:53, said:


If you elect to bid 6NT, what percentage of the time would you expect this to make, double dummy, with both the defenders and declarer looking through the back of the cards?


If I elected to bid a direct 6N, I am doing so precisely because I don't want the opponents to defending in an informed manner.
As such, the question seems rather strange...
Alderaan delenda est
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#5 User is offline   Cyberyeti 

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Posted 2019-March-14, 07:25

What I would actually do would depend on the form of scoring. I would certainly expect 6 to make more often than not, and a grand is far from out of the question (Axx, QJxxx, Axx, Ax for example), 6N is trickier and I expect its practical chances to be much higher than the theoretical ones. It's also not 100% clear whether I want partner to play 6 or whether I want to with that diamond holding, of course that will depend on partner's spade holding.

If 1N-2-2-3 is forcing I might even go that route to try to find out if partner has 5.
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#6 User is offline   etha 

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Posted 2019-March-14, 08:08

I got to 71/100 dbl dummy makes 6nt or 7nt. I might try to use the BBO deal program instead though which is better for the dbl dummy questions. I aim to make 1NT 15-17 4333 5332 4432 any.
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#7 User is offline   etha 

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Posted 2019-March-14, 08:22

and so first time I tried this but I think it was correct.

Frequency :
0 0
1 0
2 0
3 0
4 0
5 0
6 2
7 1
8 1
9 0
10 3
11 14
12 56
13 23
Generated 4997 hands
Produced 100 hands
Initial random seed 1552573274
Time needed 0.917 sec
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#8 User is offline   rhm 

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Posted 2019-March-14, 08:24

4S is ok and bid 6NT if there are at least 2 aces. I assume you can stop otherwise at a lower notrump level.

Rainer Herrmann
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#9 User is offline   rmnka447 

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Posted 2019-March-14, 09:20

I'm thinking along Cyberyeti's lines.

Likely this hand will make anywhere 10 to 13 tricks, so some sorting out needs to occur. Opener with 15 leaves enough room for the opponents to hold 2 As and a Q, or, an A and 2 Ks. Even holding 17 the opponents could hold an A and K. Nonetheless, chances for slam seem pretty good. And, as Cy points out, grand could even be there opposite the right minimum.

So I want to force showing and make a slam try by cueing if partner doesn't have length. The concern is the 2 suits without any controls in this hand.

The only time I might consider leaping to slam is late in an Open Pairs event where I was sure I needed some tops to place.
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#10 User is offline   rhm 

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Posted 2019-March-14, 11:12

View Postrmnka447, on 2019-March-14, 09:20, said:

I'm thinking along Cyberyeti's lines.

Likely this hand will make anywhere 10 to 13 tricks, so some sorting out needs to occur. Opener with 15 leaves enough room for the opponents to hold 2 As and a Q, or, an A and 2 Ks. Even holding 17 the opponents could hold an A and K. Nonetheless, chances for slam seem pretty good. And, as Cy points out, grand could even be there opposite the right minimum.

So I want to force showing and make a slam try by cueing if partner doesn't have length. The concern is the 2 suits without any controls in this hand.

The only time I might consider leaping to slam is late in an Open Pairs event where I was sure I needed some tops to place.

What information will you find out to bid a grand with confidence? How likely are 13 tricks anyway?

What information will you get which will enable you to avoid a small slam except when 2 aces could be missing?
We could of course be missing the first 2 tricks in spades or diamonds, but this is hard to find out and opponents have been known not to find the right opening lead when that was the case.

It is true that opponents could have 2 aces, but it is unlikely given the HCP distribution you know already and if opener has 2 aces slam is odds on.
Meanwhile when opener has 2 aces any slow auction will give the opponents a better chance to find the right opening lead should a small slam not be cold.
Sometimes simple is best.
I see no merit whatsoever going slow here.

Rainer Herrmann
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#11 User is offline   Cyberyeti 

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Posted 2019-March-14, 11:31

View Postrhm, on 2019-March-14, 11:12, said:

What information will you find out to bid a grand with confidence? How likely are 13 tricks anyway?

What information will you get which will enable you to avoid a small slam except when 2 aces could be missing?
We could of course be missing the first 2 tricks in spades or diamonds, but this is hard to find out and opponents have been known not to find the right opening lead when that was the case.

It is true that opponents could have 2 aces, but it is unlikely given the HCP distribution you know already and if opener has 2 aces slam is odds on.
Meanwhile when opener has 2 aces any slow auction will give the opponents a better chance to find the right opening lead should a small slam not be cold.
Sometimes simple is best.
I see no merit whatsoever going slow here.

Rainer Herrmann


Grand (in clubs) is less unlikely than you think, partner needs the missing aces and either AKJx/AKxxx or QJxxx (and I'll take the odds on Qxxxxx) to be good.

If I was going to just punt or ask aces and punt, I would punt 6 at teams unless a double indicated I should put partner in the hot seat in 6N. Obviously this can be wrong (AQxx, Qxx, KJx, Axx), but can also be right (AKx, xxxxx, Axx, Ax)
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#12 User is offline   etha 

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Posted 2019-March-14, 11:39

6c was better than 6nt exactly once in the 100 dbl dummy sim.
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#13 User is offline   Cyberyeti 

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Posted 2019-March-14, 12:36

View Postetha, on 2019-March-14, 11:39, said:

6c was better than 6nt exactly once in the 100 dbl dummy sim.


Double dummy I'd kinda expect that, single dummy less so
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#14 User is offline   HardVector 

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Posted 2019-March-14, 21:00

This is a normal kind of hand for most systems. It's usually covered by bidding Stayman followed by bidding 3 of a minor. This is forcing and shows a good 6 card minor with slam interest. It no longer promises a 4 card major. If you are playing 4 suit transfers, then the meaning changes. Now you are promising 6 card in the minor with 4 in a major. If playing 4 suit transfers, I'd transfer to clubs, then bid 3n to show a good 6 card suit that is balanced and has interest in slam.
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#15 User is offline   nige1 

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Posted 2019-March-14, 21:46

Lamford asks 'Partner opens 1NT, 15-17. You can transfer to clubs with 2S and bid minorwood for clubs or you can bid 4S (Gerber). If you elect to bid 6NT, what percentage of the time would you expect this to make, double dummy, with both the defenders and declarer looking through the back of the cards?'
++++++++++++++++++++++++++++++++++++++++++++++
I rank
1, 4 = ART (Gerber)
2. 6N = NAT (Punt).
3. 2 = TFR. 6 is sometimes better but scores less.


/** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
tricks.ds.
Trick expectation at double-dummy.
Dealer by Hans van Staveren & Henk Uijterwaal
*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** **/
predeal east S76, HAKT, DQT, CKQJT94

# 1N opener
ntHCP = 16
wHCP = hcp (west)
w1N =
(shape (west, any 4333 + any 4432) and
ntHCP - 2 < wHCP and wHCP < ntHCP + 2) or
(shape (west, any 5332 + any 5422 + any 6322
- 5422 - 4522 - 6xxx - x6xx) and
ntHCP - 3 < wHCP and wHCP < ntHCP + 1)

# Tricks test.

produce 100
condition w1N
action
frequency "Notrump tricks, West" (tricks( west, notrump), 10,13),
frequency "Club tricks, West" (tricks( west, clubs), 10,13),

Frequency Notrump tricks, West:
Low 5
10 6
11 27
12 41
13 21
Frequency Club tricks, West:
Low 1
10 2
11 32
12 42
13 23
Generated 3213 hands
Produced 100 hands
Initial random seed 1552620969
Time needed 1.797 sec
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#16 User is offline   lamford 

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Posted 2019-March-15, 06:29

View Postetha, on 2019-March-14, 08:08, said:

I got to 71/100 dbl dummy makes 6nt or 7nt. I might try to use the BBO deal program instead though which is better for the dbl dummy questions. I aim to make 1NT 15-17 4333 5332 4432 any.

I got similar:
7 8 9 10 11 12 13
3 5 2 2 15 32 41
where the top line is tricks, and the bottom line is percentage. 1000 trials. I used Bridge Analyser, which is certainly simpler than the one Nigel used which I found hard to follow.

I bid 6NT and partner had AQJx QJ AJxx xxx and he guessed to take the diamond finesse which worked rather than the spade finesse which didn't. He thought that the opening leader was more likely to lead a major on an uninformed auction. I jested "I did not know we had switched to a weak NT, pard?". He disagreed, but his K-R of 13.65 was the silver bullet. Mine was a massive 17.40, so an obvious 6NT, but he claimed the credit for guessing which finesse to take!

And FWIW I disagree with using Gerber, or other snail-like approaches, as you might well want to risk being in 6NT off two aces, as there is only a 25% chance of the leader having both.

"There was a break-in at the Libyan Embassy despite the presence of an uninformed police officer standing outside" - The Grauniad, 1984
I prefer to give the lawmakers credit for stating things for a reason. - barmar
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#17 User is offline   Cyberyeti 

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Posted 2019-March-15, 06:41

View Postlamford, on 2019-March-15, 06:29, said:


And FWIW I disagree with using Gerber, or other snail-like approaches, as you might well want to risk being in 6NT off two aces, as there is only a 25% chance of the leader having both.



If you're in 6N off 2 aces, 2/3 of the time one of them is A and you won't have 12 tricks without the clubs so they'll get a second go in fact it's difficult to think there is any chance of 12 tricks without opps having a second chance to get it right too often. OL's partner having 2 aces isn't going to work well unless partner habitually opens 1N with 6 hearts and he leads the wrong suit.
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#18 User is offline   lamford 

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Posted 2019-March-15, 12:44

View PostCyberyeti, on 2019-March-15, 06:41, said:

If you're in 6N off 2 aces, 2/3 of the time one of them is A and you won't have 12 tricks without the clubs so they'll get a second go in fact it's difficult to think there is any chance of 12 tricks without opps having a second chance to get it right too often. OL's partner having 2 aces isn't going to work well unless partner habitually opens 1N with 6 hearts and he leads the wrong suit.

Of course, most of the time you are off one ace, and going slowly gives them the chance to double something. If you knew you are off two aces, you would of course not bid slam, that I agree. The scenario where they let it through off two aces is just an extra bonus. If partner has a 15 count, the opponents have ten. They are only about 20% to have two aces in a combined ten-count.

We are weighing up whether to find out about two aces missing. Here 4S was Gerber, and LHO doubling with KQ, or just one of those cards, is a bigger danger.
I prefer to give the lawmakers credit for stating things for a reason. - barmar
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#19 User is offline   Cyberyeti 

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Posted 2019-March-15, 16:15

View Postlamford, on 2019-March-15, 12:44, said:

Of course, most of the time you are off one ace, and going slowly gives them the chance to double something. If you knew you are off two aces, you would of course not bid slam, that I agree. The scenario where they let it through off two aces is just an extra bonus. If partner has a 15 count, the opponents have ten. They are only about 20% to have two aces in a combined ten-count.

We are weighing up whether to find out about two aces missing. Here 4S was Gerber, and LHO doubling with KQ, or just one of those cards, is a bigger danger.


LHO doubling with K is exactly what partner wants to hear if he has AQ, and you also have the option of bidding 6 so the holder of the spade honour(s) is on lead.
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#20 User is offline   miamijd 

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Posted 2019-March-15, 16:51

Just as an aside, why are you using 4S as Gerber rather than 4C? Using 4S, you can't sign off at 4NT. What is the gain?

Cheers,
Mike
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