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All comments by Doug Bennion
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Mr Bethe is right … DF will take more tricks than declarer. However the studies are also right, showing a small advantage to human declarer results. How so?

A human declarer cannot outplay a DD analyser. DF effectively peeks, and that makes it stronger than any human. Note however this is not the same as saying a human declarer cannot outplay a computer declarer; any decent player can. Typically the computer declarer deals a sample of suitable deals (which conform to the auction), DD-analyses those positions, and selects the optimum play based on that sample.

Several previous studies (including mine, long ago) suggest that dealer advantage due to imperfect leads, is in the range of 0.50 to 0.75 tricks. I’ll call it 0.60 tricks. These studies of the playing data are showing a smaller advantage in the range of, say, 0.25 tricks.

The smaller advantage actually makes a good deal of sense. The dealer advantage is worth 0.60 tricks, but that is reduced in the studies to 0.25 tricks, because subsequent to the initial lead, the human declarer underplays the DD analyser, apparently by approximately 0.35 tricks (human must underplay the analyser which sees all information).

Put a little differently, the studies compare human declarer play with human leads, to DD declarer play with DD leads. Humans ‘win’ that comparison by 0.25 tricks. However we know from previous studies that human leads gain declarer 0.60 tricks, so DD declarer play is stronger by the difference, or 0.35 tricks.

So rather than illustrate the superiority of human declaring, I think the studies quantify the superiority of DD declaring, in the range of ~ 0.35 tricks.

If your objective was to more aptly compare human declarer play to DD play, you might consider a 51-card DD solution (DF optionally could provide this). You would front-end some kind of ‘rules-based’ leads for play number one. For that one play, DF would not peek. The ‘rules’ would mimic (crudely, and unless you wanted to build bidding engines, devoid of any clues resulting from an auction) the kind of thought a human leader puts into his choice … top of honor sequence, singleton if looking for a ruff, 4th best of unbid suit, blah blah. With an error-prone lead, but perfect subsequent play, that analysis would better emulate results in the real world, I think.
May 6, 2013
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You can also use those Transfer Double ladders after any (X) Y (Z) auction, provided you are willing to give up your normal meaning for DBL … here, usually penalty, sometimes Snapdragon. You gain a transfer into the 4th suit, plus an additional raise-type. For example (1) 1 (1); then

DBL = transfer into 2 cuebid, say a limit raise
1NT = normal, for positional considerations
2 = transfer to
2 = constructive raise
2 = normal minimum raise

You don't need limit yourself to Advancer position. The Transfer Doubles work well at Opener's first rebid, in Support Double position. You retain all the benefits of Support Doubles, and gain a transfer. For example 1 (P) 1 (1); then

DBL = transfer to
1NT = normal
2 = rebid!
2 = stronger raise (maybe ‘stronger’ for you here, is 4 trumps, in keeping with Support Double theory)
2 = weaker raise (3 trumps if you like Support Doubles)

Note the Transfer Doubles work nicely beyond the normal range for Support Doubles … after 1 (1) 1 (3) then

DBL = transfer to (transfer reverse here)
3 = stronger raise
3 = weaker raise
May 2, 2013
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I could be wrong, but looks like to me that Mid Chart expressly permits (8) any strong opening bid (15+ HCP), so shortness in strong no trumps is permitted, but not weak.
April 13, 2013
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If 1NT was weak, you might want to get in their face before doubler can reveal his suit.

XX = our hand
2C = MM at least 5-4, 2D by opener = same length
2D = any single suiter, then usually 2H by opener but 2S can be super-accept in hearts
2M = 4M5m
2N = mm with better diamonds
3C = mm with better clubs

Use same thing over Capp 2C, with X = MM. With good hand, pass then judge.
Feb. 11, 2013
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I usually play a weak notrump, making it even more important to cope with disrespectful opponents. Probably half the time, the opps play Capp against us (why, I have no clue). To counter the Capp 2C bid (some long suit), if you are balanced pass and find out what their suit is, then you and pard decide if X is primarily penalty or negative. If you are unbalanced, get in their face with this, which is kind of Capp over Capp:

X = (54)=x=x, with 2D response = ‘you pick’
2D = any long suit, forcing 2H except 2S = super-accept in hearts
2M = 4M plus 5m, opener passes or can bid a 5-card suit up the line, or can ask m with 2N

2NT = x=x=5=4
3C = x=x=4=5

Do the same over a DONT X, with 2C = (54)=x=x
Jan. 19, 2013
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I've played this for years. For midchart events we suggest this defence: X = a heart overall, 1S = a takeout double of clubs and spades.

For the 1S transfer response, which we play as simply ‘no majors’, we suggest X = majors.
May 4, 2012
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I have been playing transfer responses to 1C for a couple of years. The Toronto clubs allow them (because they are trivially easy to defend), and I tend to stick to mid-chart tournament events (where yes, it gets very tiring pre-alerting them).

They are particularly beneficial for weak notrumpers, where the 1C opener is often a strong notrump, so the M transfers right-side many M contracts that would otherwise be played by the weaker hand. The nebulous 1S response (no majors) often right-sides a NT rebid. Also the transfers give opener a ‘bonus’ M raise. After 1C 1D(h); you can ‘raise’ with 1H to show some kind of hand, and 2H to show another.

I like them so much I stuff all 15+ balanced hands (including shapes like 3=3=5=2) into the 1C basket. This also benefits your 1D opener, which is now always unbalanced and usually 5+ in length.
Jan. 23, 2012
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Thanks. I often play a weak notrump, so we have more disturbances than most. I'd say more than half of our opps play Capp against us (God knows why, but there you go). I've found this system useful. Over the 2C Capp overcall (some 1-suiter), we play this pretty aggressively:

X = usually Garbage Stayman, but can be start of invite+ sequence (basically responder must have something sensible to do over 2D rebid)

2D = multi-like 5+ hearts or 5+ spades, with 2H normal response = pass/correct; opener can immediately super-accept in hearts with a 2S bid.

2M = 4M plus 5-6 m, competing. Lacking a 4M-fit or attractive 4-3M fit, opener rebids any 5-card suits along the way to 3m, with 2N the m-ask

2N+ = Lebensohl

Similarly applied to the DONT X (1-suiter), with 2C being Garbage Stayman etc.
Aug. 15, 2011
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