[FrancesHinden]

That famous 7♥ hand from, I think(?), the Cavendish.... now you're going to want me to remember it exactly and I can't, but dummy was something like

AKxxx
AJx
x
KQxx

and declarer was something like

J10x
KQ9xx
AJxx
A

and LHO had entereed the fray with a jump overcall in clubs

(someone will be able to remember the hand I'm talking about and point to the thread that discussed the play, at length).

Declarer took what was close to a 0% line, and definitely missed some much better lines.

The defence mis-defended twice.

[bhall]

Strong partnerships are most important. You will more consistently reach good contracts, even in the face of competition, and you will defend more accurately. Also, the occasional dumb mistakes and missed opportunities will not cost so much in terms of partnership morale.

The problem for pros who spend most of their time playing with weak clients is that they have to shed their ingrained tendency to bid and play both sides of the table, if they are going to get the best out of a partner of equal skill. The emergence of more team sponsors in the U.S. has definitely improved the performance of U.S. teams by providing the opportunity for more top-level partnerships to form and play frequently together.

So I would add to Hrothgar's list the number of top pairs in a given country that play primarily as a partnership.

[cherdano]

awm, on Sep 19 2007, 02:41 PM, said:

Obviously all six are essential. But I think the top players are a lot closer in declarer play than many of the other aspects (in other words, the percentage of hands where the best declarer in the world would make it but another bermuda-bowl-caliber declarer will go down on the same auction and defense is extremely small). This is not to say that anyone whose declarer play is truly "bad" has even a remote chance in a bermuda bowl (they don't). I'd expect the swings to be (from most imps to least):

5. Judgement in competition
6. Opening lead
3. Defense after opening lead
1. Slam bidding
4. Game bidding
2. Declarer play

I wonder whether you are answering a different question Adam. There is the question

• (A) "Which skill area will cause most IMPs to be swung?" and
  
• (B) "In which skill area will the better teams gain the most IMPs over the average teams?"

I agree that opening lead choices will swing many IMPs, but do you also think these swings will usually go to the better team?

Well actually I am pretty sure Adam is aware of this difference and maybe he is right that e.g. the Italians win more IMPs on the opening lead than on the subsequent defence, but I would have thought otherwise. In fact I think many overestimate the importance of bidding due to mixing up the two question. Iif the better team bids 60% slam and the other table doesn't the kibs will see a 10 IMP swing every time but in fact the other team is only EV -2 IMPs due to the bidding. However, if one table is in a vunlerable game and the other not, and declarer takes a 30% line instead of a 40% line, then kibs might not even notice but in fact declarer lost EV -1.6 IMPs on the play. These kind of EV swings happen pretty often, I think.

[awm]

A lot of imps are going to fly back and forth due to "luck" -- one table bids a close slam and the other doesn't, or two declarers take different lines where one makes and one doesn't. There will even be times when the technically inferior action wins a bunch of imps due to luck, but the matches (at least in the KO stage) are long enough that this should tend to balance out.

So I assume the question being asked is "which skills are most likely to make the difference between who wins and who doesn't." I may be in a minority in this, but I believe that the different results from opening leads are not "mostly luck" (i.e. they swing a lot of imps but it's mostly randomness) but in fact have a large element of skill, and that there is a substantial difference in opening lead style between the partnerships who are most successful on defense (i.e. Fantoni and Nunes) and the less-successful pairs. Also, good partnerships play a lot of complex defensive signals, and I think most bermuda-bowl-caliber pairs are not that likely to misdefend at trick ten (for example). Of course fatigue is a factor and maybe I'm wrong about these things.

[han]

awm, on Sep 20 2007, 02:48 PM, said:

Also, good partnerships play a lot of complex defensive signals....

Is that true, and is it complex signalling methods that makes the difference between a top and a mediocre partnership's defense?

I didn't know that most good partnerships use complex signalling methods, I rather thought that rather they would make optimal use of the signals they do play. For example, I'd expect them to know more often when they should give what kind of signal, and when they should refrain from signalling. Of course, they also know better what signal partner is giving and what they should do with the avaliable information.

So what are these complex signals that good partnships play? Should I start studying them?

[Gerben42]

there is an example in Sabine's book where 3 cards are played, all 6 possibilities have a meaning. No doubt more pairs do similar stuff.