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All comments by Doug Bennion
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David: Thanks for verifying. I'm getting roughly comparable matchpoint results. For example for AKxxx suit, 1NT wins/ties/loses 44/26/30%, and average IMP win 0.54.
Jan. 18
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Some 5-3 info. When opener has specifically 3 hearts (includes 4333), then when responder’s heart suit is 4+ HCP, 1NT makes the ‘normal’ 57%, 2 making zooms to 72%.

When opener has 3 hearts but won’t be 4333, 1NT down a bit at 50%, 2 up more to 76%.
Jan. 17
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I was curious, so looked at what kind of difference suit ‘quality’ makes in a 5-2 fit. Opener has 12-14 balanced, with 2 hearts. Responder has 7-9 HCP and 5 hearts in a 5332 hand. Sample size is 2000, large enough to be comfortable with the results.

Seems the suit quality has little impact on the chances of making 1NT, but a major impact on the chances of making 2.

When heart suit is xxxxx, 1NT makes 55%, 2 makes 28%

When suit is Qxxxx, 1NT makes 55%, 2 is creeping up at 35%

When suit is Kxxxx, 1NT makes 57%, 2 makes 39%

When suit is QJTxx, 1NT makes 56%, 2 makes 46%

When suit is AKxxx, 1NT makes 63%, 2 makes 46%

When heart suit has a generic 4+ HCP, 1NT makes 62%, 2 makes 45%
Jan. 17
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When responder has specifically 5 hearts, opener (given same constraints) has 1/2/3 hearts 5/34/61%.

You're welcome.
Jan. 17
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On the off chance it is useful information, I've simmed the chances of opener's heart length. Responder has 4-5 hearts, spades not longer, and minors < 6. Opener is balanced with 2-3 hearts, or specifically 3-1-(45) (with 4 spades he can easily rebid 1, with another minor he has a natural convenient rebid).

Given those constraints opener has 1 heart 4% of the time, has 2 hearts 33%, and has 3 hearts 63%.
Jan. 17
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That's true. If opener might raise with a balanced hand with just three hearts, cancel what I wrote.
Jan. 16
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If responder is not 5332, he should rebid 2.

If opener promises with 1NT to be balanced, responder should rebid 2. A 5-2 fit under those conditions will play marginally better in 1NT, but a 2 contract will play substantially better in 2, and opener will have three hearts more often than two hearts.
Jan. 16
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The notrump hand often has positional value so we exclude xNT from all transfer ladders. Here, 1 (X) XX would show clubs, and 1NT would be ‘natural’.
Jan. 11
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Partner is encouraged to find a bid when faced with (2) P (P).

I found some ‘work’ I did awhile back, but didn’t bother posting. When RHO has a 6-card major, you will see these hands:

54% will be balanced (including 4432 4333 5332 5422))

24% have a 6-card suit (8% each for other major, and two minors). Amusingly, 1 in 20 of those 6-card majors will be in opener’s suit

6% have unbalanced 5-card major (1 in 7 in opener’s suit)

8% are suitable for takeout of major (41)(53) and (41)(44) and (40)(54). A full one in six are for the ‘wrong major’

Balance are some 2-suiters and hands like (31)(54) and (43)(51) which are awkward to bid even when opening suit is known.
Jan. 11
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First time around, don't bother with the takeout doubles because (1) you won't have the right shapes very often and (2) a good chunk of the time you will be takeout doubling for the wrong suit (you'll be 4144 and opener turns out to have spades).

X = hearts
2 = spades
2 = stronger balanced, say 16-19, systems on
2NT = weaker balanced, say 13-15, systems on

3m = natural NF

Start Mm two-suiter with a Transfer.
Jan. 11
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I've played a weak notrump most of my life, and can count the number of times I got nailed good, on my fingers and toes. Most weak-notrumpers can (almost always) wriggle out of trouble, or the trouble they do get into isn't fatal, because the opps have a nice game they did not or could not negotiate.

So if a penalty double of a weak notrump doesn't work for my opps, it shouldn't for me.

When RHO opens a weak notrump, and I have the same approximate strength and balanced shape, I think X is best played with the primary consideration that you are competing for a partial, because game by either side is unlikely. So your partner treats the X as if you had opened a weak notrump, with full systems on, including transfers and some kind of scrambly Stayman. Partner can always convert to penalty of course.
Jan. 11
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The double dummy solvers do a good job compiling overall contract results, but not so good on analysing deals one-on-one. I think. I use DealMaster Pro, maybe other analysers do a better job. Or maybe I’m missing something with DM Pro.

Example. I was interested in how 4 fared against 3NT when both hands were 12-14 balanced, and both hands had 4 spades. For that comparison, I specified the responding hand was never 4-3-3-3, because with that hand responder would not bother to look for the major fit.

The software told me that 3NT makes 61% of the time, and 4S makes 57%. Pretty much a tie, very slightly favoring 3NT. The sample was 3000 deals, which won’t wring out all randomness, but is probably accurate within a percent or two.

However that summary doesn’t tell me how those two contracts matchpoint. When both 4 and 3NT are making, 4 ‘wins’ at matchpoints. As far as I know, DM Pro gives me no way to easily test a head-to-head comparison of two contracts.

I can cludge some code, so I wrote a back-end to DM Pro which lets me compare head-to-head. Turns out that at matchpoints, 4 beats 3NT 49% of the time, ties 14% (all equal downtricks), and loses 37%, so looks like you should keep using Stayman at the club. Scoring by IMPs is a virtual tie.
Jan. 9
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We play transfers beginning with X, in any position where (1) three suits have been bid (2) partner has bid one of them, and (3) X is a legal call. This position qualifies. We play the transfers through (partner - 1), and we skip notrump because it has positional value.

So here, X = good club raise, and 3 is a courtesy raise.

After X, if overcaller is strong enough with four hearts, he can try 3 after partner's expected 3 rebid. Or advancer seeing X and strong enough, can try 3 himself.
Jan. 5
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Once we included 5M332 hands into our weak notrump openings, it only seemed sensible to include them in our strong notrump openings as well, even though we open those 1. Knowing partner's 1M openers are never balanced, is like a breath of fresh air.
Jan. 4
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Thanks Kerry I'd forgotten I wrote that.
Jan. 3
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Phew, due to the nice spots, K&R elevates that hand to 15.05. Without the 9's and T, it comes in at 14.60.
Jan. 3
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There were no results beyond those values that came out of the analysis which you previously mentioned. I had intended a broader scope, maybe dummy points for shortages, etc, but it stopped being fun, so I stopped.
Jan. 3
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Kerry: That first scale I described in an article (or maybe it was a letter) to the Bridge World a couple of decades ago. I used a pile of simulation results to develop the values, given a beginning point of jack = 1. I think I went on to suggest you add 0.5 or maybe it was 1.0 point, to most combinations of honors.
Jan. 3
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Here are large-sample comparisons human vs double dummy results http://www.rpbridge.net/9x29.htm
Dec. 30, 2017
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