[Vampyr]

billw55, on 2012-June-04, 07:15, said:

Would've been a good time for a support double over 2♠. If I don't have that agreement, I probably don't have one about 2NT either...

Are these agreements somehow related?

[billw55]

Vampyr, on 2012-June-04, 17:09, said:

Are these agreements somehow related?

Only in the sense that the former is perhaps simpler than the latter .. so that it would more likely be added first. Might just be my perception though.

[SteveMoe]

Not sure I like the double from the strong hand. With 19, slam is in the picture. Partner's pass shows no penalty double (assuming support doubles through 2♥) with an opening hand. 3♠ cue bid instead of the double would elicit 4♣ from opener and cue bidding gets us to 6♣.

Given the actual auction, I think 3♣ is indicated over the double. 2N should be scrambling or Lebensohl, so the 3♣ call is forward-going. Partner should now be alive to the possibility of a ♣ slam and cue bid 3♠ on the way there...

[aguahombre]

mgoetze, on 2012-June-04, 15:33, said:

You can take the diamond finesse either way of course. But my question was really: are the odds of getting the diamond finesse right high enough to bid grand, given that one of the suits is "known" to break 3-6?

I don't think so. It would be close if the diamond queen and the spade suit were the only mathematical considerations. But, there is the possibility that you will also need the diamonds to come in for 4 tricks, not just 3 (4-1 club break).

[kayin801]

aguahombre, on 2012-June-04, 20:58, said:

I don't think so. It would be close if the diamond queen and the spade suit were the only mathematical considerations. But, there is the possibility that you will also need the diamonds to come in for 4 tricks, not just 3 (4-1 club break).

It's a decent mathematical play problem if preemptor shows out on the second round of clubs. Win opening spade lead, Cash 2 rounds of clubs with honors in hand, see E show out, and test hearts. If they are 3-3, you 'know' diamonds are 3-3 (assume 3334 vs 6331) and you just need to guess the suit. If hearts are 4-2 (3424 vs 6241) now you pitch a spade, ruff, draw trumps and guess. You'll also make when preemptor is 6151. Granted you fail against 3244 vs 6421, with preemptor having the diamond Q. But yes, it still comes down to guessing the diamond Q, which ultimately seems a tossup.

I think any scenario where spades are 7-2 increases our chances.

[mgoetze]

billw55, on 2012-June-04, 20:08, said:

Only in the sense that the former is perhaps simpler than the latter .. so that it would more likely be added first. Might just be my perception though.

Just because an agreement is simple doesn't mean you should add it. For example, the agreement that any 3NT overcall shows 10-12 HCP balanced is very simple, yet noone seems to have added that one.

I know one pair who would play support double in this situation but they're not very good.

[gnasher]

Apart from the 6=4=2=1 case mentioned by kayin801, 7♣ will come down to knowing the diamond distribution and then playing with the odds. At the critical moment, if we know the spade distribution we will also know the diamond distribution.

Given that, we will make 7♣ against half of the 3-3 breaks, 2/3 of the 4-2 breaks, and 5/6 of the 5-1 breaks. If diamonds are 6=0 I assume that we're going to suffer a first-round ruff.

Using Pavlicek's calculator to obtain the suit-break probabilities given spades 3=6, we get:

3-3: 33.94%
4-2: 48.36%
5-1: 15.95%

So the chance of making is

33.94 / 2 + 48.36 * 2/3 + 15.95 * 5/6 = 62%

minus a bit for the 6=4=2=1 case, plus a bit for a 2=7 spade break (which increases the chances of the uneven distributions and therefore improves our odds).

Thus the probability of making is above the theoretical 56% threshold. However, the opponents may miss slam, or play in the wrong small slam, so in practice the odds aren't good enough.

[Vampyr]

billw55, on 2012-June-04, 20:08, said:

Only in the sense that the former is perhaps simpler than the latter .. so that it would more likely be added first. Might just be my perception though.

mgoetze, on 2012-June-05, 01:53, said:

Just because an agreement is simple doesn't mean you should add it. For example, the agreement that any 3NT overcall shows 10-12 HCP balanced is very simple, yet noone seems to have added that one.

Also, not everyone constructs their bidding system by tacking on conventions willy-nilly in some sort of order of perceived complexity, though something like this happens with, say, once-a-month partnerships that do not get together for system discussions -- every time they play they will adopt a favourite treatment of one of the partners! The order will not be about complexity, though -- it will have more to do with the degree that the favourite treatments are liked.

About support doubles in particular -- are they really so popular in Strong-NT-Land?

[mgoetze]

Vampyr, on 2012-June-05, 04:16, said:

About support doubles in particular -- are they really so popular in Strong-NT-Land?

Support doubles up to 2 of our major are very popular.

[Vampyr]

mgoetze, on 2012-June-05, 05:06, said:

Support doubles up to 2 of our major are very popular.

What about in the OP auction?

[mgoetze]

Vampyr, on 2012-June-05, 05:17, said:

What about in the OP auction?

mgoetze, on 2012-June-05, 01:53, said:

I know one pair who would play support double in this situation but they're not very good.

[billw55]

So I guess it is just my perception

[ChrisV]

Call me nuts but if I want to show that I have clubs as well as diamonds here, I just bid clubs. There's no advantage to bidding 2NT instead, it will just confuse partner.

If 2NT is bid, the other hand has to make the only unambiguously forcing bid available, which is 3S. When you have a strong hand it's often better to ask rather than describe. Being in possession of more information about that partnership's assets, you are better placed to choose the contract.