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All comments by Kit Woolsey
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Yes, when 2 goes down 2 tricks and 3NT is bid and made at the other table, the gain from doubling will be 4 IMPs, not 5 IMPs.

There are other possibilities. if 3NT is making at the other table and 2 goes down 3, the gain from doubling is 9 IMPs (+3 instead of -6).

If 2 goes down 2 and the contract is 1NT making 2 at the other table, the gain from doubling is 6 IMPs (+5 instead of -1).

The bottom line is that the other table result isn't going to have much effect on the swing from doubling.
Feb. 17
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Thanks Craig. Those results are very consistent with David's, indicating that small changes in the parameters have little effect on the simulation.

It is worth noting that down 3 is more common than making. The gain from doubling when down 3 is the same 8 IMPs (=500 vs. +150) as the cost from doubling when making (-470 vs. -110). That itself is sufficient to illustrate how clear the double is.
Feb. 16
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Whatever writing I did along these lines had to do with strong NT openings. 10-12 is an entirely different issue. If the distribution and the strength is right for the 10-12 NT, just do it regardless of honor placement.
Feb. 16
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Feel free to tweak he parameters as you see fit. I chose the parameters I did because they are simple and reasonably accurate.

A couple of observations:

The only shapes which we would not be opening 1NT (which the suggested parameters allow) are 5-4-2-2 hands with a 5-card major. Note that since West can't have 4 spades (since I specified that opponents have at least 7 spades), these would involve West having a doubleton spade – unfavorable for the double. Thus, eliminating 2=5=4=2 and 2=5=2=4 shapes would make the double a little more attractive in the simulation.

Anybody who doesn't act over a 10-12 NT with a 14-count is just asking to be stolen. 13-point hands are admittedly more marginal. If you want to run the simulation constraining North to 14+, that is fine. That figures to make the double a little less attractive.

As to shapes for the double: If you allow the doubler to have a singleton, that singleton will often be a spade. This would make the double considerably more attractive, which is the main reason why I chose to say that the North hand has no singletons – although in real life some players do make a penalty double of a 10-12 NT with a singleton.

I think that most players will double with 5-4-2-2 hands (except 5-4 in the majors, but North can't have that). However, if you want to eliminate 5-4-2-2 shapes, go ahead. That would make the double of 2 a little less attractive.

So, the parameters which are as unfavorable for the double of 2 as possible would be:

West: 10-12, no singletons, voids, or 6-card suits.

North: 15+ HCP, no singletons, voids, 6-card suits, no 5-4-2-2 hands.

South: 5+ spades

Even with these modifications, I predict that the simulation will have the double of 2 being a significant winner.
Feb. 16
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Thanks, David. Those results are quite convincing, even more so than I had anticipated. Even if we tweak the parameters slightly (like making the North hand 14+ HCP) and take into account the practical “declarer advantage” (which as David implies is greater for part-score hands than for game hands), doubling will still come out to be the percentage action by a fair amount.

Just for completeness, what were the exact results (i.e. how many times did the contract go down 3, make an overtrick, etc.). while I can guess at these, it would be interesting to know them.

Of course one must take into account the psychological factor of the 8 IMP loss when 2 doubled makes. How much this is will depend upon the individual player. I have a pretty thick skin. Also, for me the cost of not doubling and getting +150 instead of +500 is as devastating as the cost of doubling and getting -470 instead of -110. Others may feel differently.
Feb. 16
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I think all good players would make a penalty double of a 10-12 NT with a 14-count. If you prefer 14+ for North, fine. I don't think it will change the results much.

You say things are so favorable for E-W. Are they? West has only a 10-count. The ruffing finesse in clubs is onside. N-S have a secondary fit in diamonds. The queen of diamonds is onside. These are all favorable factors for N-S. The only really favorable factor for E-W is West's third trump.

Thee isn't much point in arguing these factors. The simulation will give us the answer.
Feb. 16
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I never claimed that 2 down is most likely. What I said is that down 2 is more likely than the contract making. And that is sufficient to make doubling a favorable proposition.

I could be wrong with my estimation, of course. I think this is the type of problem where a simulation will be very instructive. I propose the following parameters:

West: 10-12 HCP, no singletons or voids or 6-card suits.

North: 13+ HCP, no singletons or voids or 6-card suits.

South: 5+ spades.

These parameters might not be perfect, but I think they are close enough to reality to give us a very good picture of what is going on.

If somebody would run the above simulation, we would all be very interested in the results.
Feb. 16
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It might be. I don't think it really makes much difference.
Feb. 16
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While obviously the jack is the right play, I find it hard to believe that West would duck AKQx looking at the jack in dummy. It can't gain, an could easily lose a tempo or help declarer play the hand.
Feb. 14
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I'm sure David has some theme in mind, but if this isn't a model limit raise in clubs, what is? Too bad about the fifth club I don't have but partner is allowed to have 4+ clubs for his 1 opener and if he doesn't he is allowed to have a spade stopper and bid 2NT.
Feb. 12
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If both East and West had passed, likely 8 tricks would have been taken. Check the recap sheet, and see what the E-W matchpoint score for -120 would be. That score should answer your question about whether or not E-W should get in the auction.
Feb. 11
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I wasn't able to find the par problems online.

The WBF had pamphlets with the par problems and their solutions. I was unable to find my copies. However, I'm sure that some Bridgewinners reader has a copy of the hands, and would do everybody a great service by posting them. I can't imagine the WBF would object.
Feb. 10
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I agree that is brilliant. It is the sort of end position I was trying to find, but I was looking at West having the heart length, not East.

I agree that both red suits splitting is more likely. As Franco says, having West show out on the first round of diamonds (and it clearly can't cost to draw one round of trumps) may make his solution the only possibility. If his analysis holds up, it is on a level with Bernasconi's par problems.
Feb. 10
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Playing for both red suits to split is the obvious line. However, if West plays honors on the first two rounds of hearts, I think it is percentage to play him for 5-2-1-5 distribution – draw one round of trump, pitch a heart, and take a ruffing finesse. Double restricted choice makes West much more likely to hold a doubleton heart rather than QJ10 tripleton, not to mention that West might have led a heart if he held QJ10 tripleton.

I was looking for some position where West might be under pressure if he holds 4 hearts, but I couldn't find one.
Feb. 10
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Rather than bank on your table feel in the heart suit, perhaps a better approach is to win the heart shift in your hand and lead a heart to the king. If West follows, this just transposes to your planned line. However, if West shows out you can re-consider, particularly if you judge that West is thinking of ruffing or that West would have bid differently with 0-1-8-4 distribution.

Anyway, nice recovery. It is important to realize that there are certain falsecards players just won't find in real life, even top experts.
Feb. 10
Kit Woolsey edited this comment Feb. 10
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Thanks. Fixed. You are quite right about the world's worst editor. The problem is that the author knows what is supposed to be there, so he mentally sees what he thinks should be right. Somebody unfamiliar with the writing has a much better chance of spotting errors. I really appreciate readers finding these errors.
Feb. 9
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I would need to know more about the partnership agreements to answer this question.

If partner will always lead ace from AK regardless of the contract, then you should play the jack, attitude, saying you want a shift.

If partner will lead the king from AK vs. 5-level or higher contract which asks for count (a much more sensible agreement IMO), that means that declarer has a singleton king. Partner will know that you know this when the king comes down, thus making your play suit-preference, so you should play the 2.
Feb. 8
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Since East didn't overcall when he could have if strong enough (since clearly he has a spade suit), his hand is limited. Thus, I don't see how his call can logically be forcing. Granted West will seldom be passing, but if West has stretched for his balance I can see that West might judge to pass. This is quite different from if it had gone (3)-3-(P)-3. Here the 3 bidder is unlimited, so his call is 100% forcing.
Feb. 7
Kit Woolsey edited this comment Feb. 7
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I lead the king of hearts at trick 2. If they win the ace, I am going to do very well when the opponent with the doubleton heart has 3 trumps, and I will have good chances to take 8 tricks on other layouts, particularly since the defense may have to be perfect to hold me to 7 tricks.

If they duck the king of hearts, I will draw trump and play another heart. This will force them to break a minor with little information to go on. With dummy having the stronger diamond holding, there is a good chance they will break clubs and give me a trick.
Feb. 7
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Obviously your second example hand is a 1 opener.

The limits on opener's hand are normal limits. The “range” is 11-15, but of course one can use judgement both on the top and the bottom of this range. High card points are only a guideline.

If you think you want to be in game opposite your first example hand, you are looking through rose-colored glasses. Sure, if everything splits nicely you have the potential to take 4 spade tricks, 5 diamond tricks, and a club trick. However, one bad split and the hand will fall apart.

For every perfect hand you can construct, I can construct hands where game is pretty hopeless. Something like Axxx x AKxxx KJx. That is a primish complete maximum, with everything working. Do you want to try to take 10 tricks opposite that? And I could make it a lot worse, and still be a primish maximum.

Occasionally you are going to miss a perfect fitting hand where, while game is percentage it still isn't laydown. Bridge is a game of percentages, not of absolutes.
Feb. 7
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