[mikeh]

riverwalk3, on 2023-March-09, 08:57, said:

Declarer usually outperforms double dummy at the game level, because the opening lead matters a lot and the double dummy defender always makes the correct opening lead. At the slam level, the opening lead matters less, so it is about a wash. At the grand slam level, the double dummy declarer always makes the right play, so the defenders usually outperform double dummy at the grand slam level.

Also, in your "bad" examples where North had a lot of points in the red suits, he might bid 4NT instead of 4S, which discourages slam and shows strength in the unbid suits (as 4 clubs was a slam try since it commits the partnership beyond 3NT without assurance of a fit).

Thanks for making me laugh.

No, declarers do NOT ever outperform double dummy handling of suit combinations. Ever. If you think they do, I suggest a little remedial reading. Heck, you could start with my examples of suit combinations and the differences between how mere humans play them and how double dummy analysis says they can be played. Hint: the phrase double dummy means that, unlike actual players, the computer ‘knows’ how the suit breaks every time. So it never loses a two way finesse. It always drops stiff kings offside. Missing AJ10xx, holding Qxxx opposite Kxxx, anytime we have the necessary doubleton ace in one hand, humans get it wrong (absent clues) 50% of the time. Double dummy, we know where the Ax is, so invariably lead through it, ducking on the way back and so on.

Edit. There is no inherent contradiction between claiming that, on the whole, declarers in, say game, on average may do better than double dummy, on the one hand, and stating that double dummy will consistently outperform on suit combinations. The edge a good declarer may have overall is because defence is harder than declarer play and, as you noted, often the opening lead turns out to be a bad choice, viewed double dummy. That rarely helps when the problem is how to play a trump suit.

[Stephen Tu]

mikeh, on 2023-March-09, 10:30, said:

Thanks for making me laugh.

No, declarers do NOT ever outperform double dummy handling of suit combinations.

I don't think the statement you quoted claimed that. He was talking about result of whole hand at game level, not individual suit combinations. Idea being losses from suboptimal opening leads at game level from defenders on average outstrip declarer's losses from inability to play suit combos DD.

[mikeh]

Stephen Tu, on 2023-March-09, 12:24, said:

I don't think the statement you quoted claimed that. He was talking about result of whole hand at game level, not individual suit combinations. Idea being losses from suboptimal opening leads at game level from defenders on average outstrip declarer's losses from inability to play suit combos DD.

I do know that. You need to read the thread. I argued that driving to slam opposite 3 keycards, based on double dummy analysis, was an error. Merriman suggested (as I read his post, but I may have misunderstood) that on a double dummy basis slam made about 50% of the time. When we’re missing a keycard, it’s a spade much of the time and now we are often faced with Axx or Kxx in dummy. As I have tried, apparently with little success, to show double dummy analysis seriously overstates the odds of holding our losers to one trick in these combinations

It was to one of my threads advancing that pretty obvious argument that riverwalk replied by disagreeing with the notion that slam was bad and he did so expressly on the basis that human declarers outplay double dummy analysis below grand.

Do I think that in real life declarers, below grand, often outperform DD? Yes. And an expert declarer against non-expert defenders….by a wide margin, lol. But Michael Rosenberg won’t out perform DD analysis on the suit combinations I described. And he is generally regarded as being one of the finest declarers of all time.

Since few of us are as good as him, how do you think we’d do?

[Jyrki_63]

Partner and I might have chance, but I do predict our auction would peter out at either 4S or 5C.

Our system is 2/1 Transfer Walsh with a few extra agreements. The bidding would begin
1C(1) - 1H(2)
1S(3) - 2NT(4)
3S(5) - ?

Explanations:
1) Our systemic opening bid for balanced hands in this range without a 5 card non-club suit (1NT opening is 14-16, 2NT opening 22-23).
2) Transfer to spades.
3) Default acceptance (South could be very weak if they cannot tolerate clubs). Here 17-18 balanced without 4 card support would bid 1NT, so this is either 12-13 or 19-21).
4) XYZ showing a desire to play in 3C opposite 12-13 (1C only promised 2 cards, so this is usually 6), or a strong hand with 55 majors.
5) A 19-21 hand bids something other than 3C. Looking at the red aces as opposed to slower honors I would think that we want to play in a black suit.

But at this point I'm not sure about the continuation. It is not impossible to envision the actual hand, but it is usually prudent not to play partner for a perfecto. As South I would probably be happy to have located a 53 major fit, and suggest 4S. There is an inference that this might be 56, allowing North to correct to clubs. But it could simply be a judgement call, thinking that Moysian is the best chance. Particularly at MPS. It is undiscussed, to what extent 3S denied interest in 3NT? After all, North has shown 19-21 balanced with exactly 3 spades:-)

A tough hand. I'm not sure I would want to be in 6C with Jxxx trumps in the West. Is there not a danger of you getting tapped after a red suit lead? Need two ruffs to get to the long trump hand: once to lead towards QT of trumps, and the other to draw the Jack of trumps. At that point the trumps are exhausted, and the spade suit is still untouched! I guess a better timing might be to develop the spades earlier, but I'm not sure if that helps?