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Too difficult (for me)

#21 User is offline   masonbarge 

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Posted 2015-February-08, 15:33

View Postwanoff, on 2015-February-07, 13:14, said:

I was going to post this in the Expert forum but we're discouraged from doing so.
Match from this week, love all, imps, E/W are current internationals.



Where did I go wrong ?


You passed.

You do not have sufficient values to pass. You are effectively doubling a 3 level contract with one trump trick and no idea about partner's hand except 1) he has the offensive strength to play at the 3 level and 2) shortness in diamonds (!). You have one defensive trick. You have support in the unbid suits.

I would rate 3NT as the best bid and both 4 and 4 (asking for his longer major) as better bid than pass.
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#22 User is offline   1stpanda 

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Posted 2015-February-08, 17:34

Let's try to look at this carefully.

1. I doubt that bidding 4 is going to lead to our best result very often. So I am going to just analyze whether it is right to bid 3NT or pass for penalty.

What do we need to make 3NT?

A. If we have a double stopper (any diamond honor in N, or a singleton honor in E, or a doubleton honor in E coupled with an honor lead by W), then our chance are probably pretty good - in this case we need to take 7 (or 8 if our second "stopper" is a blockage) tricks outside diamonds, without letting W in twice. I would guess that we would make 3NT more than 80% of the time when we have a double stopper or a blockage. On defense, however, it makes a big difference. When we have a true double stopper, then their expected number of tricks is probably equal to LHO's number of diamonds or number of diamonds +1; we will get 100 or 300 against a 7-card suit and 300 or 500 against a 6-card suit. A diamond blockage will have little effect on their number of tricks as declarer, though, and the suit will never block when E has Hx. So they will get 1 more trick, and we will get +100 or +300 against a 6-card suit but +100 or -470 against a 7-card suit.

To summarize this case, if we have a true double stopper we will score +400 on offense 80% of the time and -100 to 200 about 20% of the time. Our expectancy is probably +290 or so on offense, and +300 or so depending on the frequency of the various results on defense. When there is a blockage, we will still have an offensive expectancy of +290, but our defensive expectancy plummets to -20 or so. So in this case it's right to bid.

B. When we have a single stopper, then we will either need to have 8 fast winners outside diamonds or find W with no entry. I would guess that these combine to about 1/3 of the time. And we will beat 3X about 3/4 of the time as above in the blockage case. So our offensive expectancy is probably around +50 and defensively about -20. Once again it is right to bid, at IMPs, to avoid the occasional huge loss (perhaps even a double game swing) by offering up a lot of small losses. Note, however, that it is right to pass at matchpoints because we will likely go plus instead of minus about half the time, and other times we will collect +500 for a larger plus.

C. If W is the sort who might "fool around" with, say, KQJ10xx and a minimum opening bid, then 3NT is going down practically all the time, likely doubled. (My experience has been that when W has opened 3 with this hand type, and we bid 3NT, W will double far more often than not.) In this case, the odds are heavily with passing, since a W with this hand type is likely to take nearly as many tricks on defense as on offense, and we have no intersecting case where bidding would result in a poorer result than passing.

So now, your job is to decide how likely cases A, B, or C are. My guess would be 25%, 70%, and 5%. But note that only in case C is is right to pass at IMPs under my assumption that 4 is futile. So I think the IMP odds for bidding are enormous; we will win 5-7 IMPs for 3NT making a large percentage of the time in case A and about 1/3 of the time in case B, while losing 3-6 IMPs most of the rest of the time. Only in case C, where passing is our only hope of a non-disaster, do I think passing has the better of the IMP odds. At matchpoints (or board-a-match) I think it is right to pass based on the frequency of small gains in case B.

Thus the basis for "Wolff's Law." It truly is wrong to pass just because you are afraid to bid. You will find that in most cases where you do an analysis of high-leverage auctions such as this one, the odds will come out similarly.
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#23 User is offline   jogs 

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Posted 2015-February-08, 19:37

http://en.wikipedia....wiki/Bob_Hamman

Quote

Hamman's Law is the maxim, "If you have a choice of reasonable bids and one of them is 3NT, then bid it."

From English Bridge, June 2006, p. 19.
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#24 User is offline   AyunuS 

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Posted 2015-February-08, 22:24

I'd say 3NT gives you the best odds. When I double at level 3, I'm generally very short in the opponent's suit. It's like just begging partner to bid something. So I'd like a little more than Axxx in the suit to pass. Preempter probably has KQJ10xxx or something in which case we still only win one trick in that suit. But partner probably has enough that you have a good chance at 3NT. Neither opponent has all that much, and you have a lot of good cards for finessing LHO so that you can deny him being able to lead again and you can duck initially until RHO runs out of diamonds. Given the preempt, 3NT is a pretty good guess for this situation.
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#25 User is offline   kevincline 

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Posted 2015-February-08, 22:49

View PostGrahamJson, on 2015-February-08, 01:21, said:

I think it was Bobby Wolff who said that when faced with a choice of calls, one of which is 3NT, bid it. I think that this is one of those occasions.


That's Hamman's Law.
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#26 User is offline   GrahamJson 

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Posted 2015-February-09, 00:16

Yes, I originally wrote "Hamman" but it got auto-corrected.
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#27 User is offline   PhantomSac 

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Posted 2015-February-09, 02:34

lol
The artist formerly known as jlall
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#28 User is offline   jpeak948 

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Posted 2015-February-09, 22:11

I think you must bid. The only bid you can do is 3nt. I dont understand why someone said 4 club? Your partner have a opening hand and ask you to bid...what do you do when your boss ask you a question? Normally, you answer? Thats the same thing. If your p dont like your 3 nt because he has no stopper and his hand is very minimum, he will adjust. Dont be chicken...if 3 D is a really weak open he has not more than 1 entry in his hand...
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#29 User is offline   Phil 

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Posted 2015-February-10, 07:33

Why is it that I can always tell from the comments when a thread gets linked in the MBC?
Hi y'all!

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#30 User is offline   mikestar13 

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Posted 2015-February-10, 15:58

Definitely a Hamman's Law case. 3NT. I rather like calling the 3NT bid "Hamman's Hammer": alliterative and evokes the image of "Thor's Hammer". Comparing Bob Hamman's stature as a bridge player to Thor's stature as a Norse god (or an Avenger, for us Marvel fans), ai'nt much of an overbid.
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#31 User is offline   blackshoe 

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Posted 2015-February-11, 13:52

Even Hamman couldn't pick up Mjölnir. B-)
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#32 User is offline   Thiros 

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Posted 2015-February-11, 15:56

I'll say for the purposes of the thread that 3NT is my choice, but my action at the table might depend on whatever information I happen to have about West's impression of our partnership's caliber. (i.e. I could be more inclined to pass if I got the feeling that his third-seat preempt was an attempt to run us.)
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#33 User is offline   diana_eva 

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Posted 2015-February-12, 03:14

View PostPhil, on 2015-February-10, 07:33, said:

Why is it that I can always tell from the comments when a thread gets linked in the MBC?


It's called the law of total posts, a function of total posts of posters and number of posters.

#34 User is offline   wanoff 

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Posted 2015-February-15, 07:33

Yes the correct bid was 3NT and maybe next time I'd get it right.
Perhaps I'd been softened up by East who earlier in the set, valued xx Jx QJ98x Qxxx as a weak 2.

3NT is still tricky as on 2 top diamonds you'd probably duck and later have to pick up clubs for 1 loser.

The hand:

tick

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