[catatonic]

you have arrived in 7NT , and had a lead in one of the 2 suits in which you are solid ;
cashing those suits first you arrive at the following ..[both suits break as evenly as possible]

Qx AKxx
QJT Ax
A

needless to say , no discard from the suits you still hold

is the vienna coup a better than the 50% of the finesse ? even though unlikely it seems to me that the small chance of dropping a singleton K is added to the 50% of the K being with 4 of my suit ...or am I missing something here

[FrancesHinden]

As a (very) general rule, the squeeze works when the two menaces are together, the finesse works half the time.

The chance of the two menaces being together is always under 50%, but the exact odds vary depending on the position and the exact nature of the menaces. Simply once an opponent has one of the menaces, he has used up more of his cards and the chance of his having the other is lower.

In your layout, if I give both opponents 6 vacant places (so no indication of shape at all), and assume all seven spades are still outstanding, then the chance of the king of hearts being with the long spades is

spades 4-3: 75.8%, king of hearts with the 4-card suit 40%
spades 5-2: 22.7%, king of hearts with the 5-card suit 20%
spades 6-1: remainder, K of hearts with the long spades 0%

giving a total of 35% for the squeeze

That makes the finesse much much better odds.
I don't know what the chance of singleton HK offside is because that will depend on how many hearts you had between the hands originally.

Usually it's rather closer, because you usually have a bit more information about the vacant places.

[catatonic]

how disappointing , can't remember the last time I played a vienna coup , much more elegant !

as a matter of fact the dummy was 4333 , declarer 2344 opps both 43 in the minors and the discard so far seen was a heart

[BillHiggin]

Such a shame you had the ♥J10!
Without those, the Vienna Coup would be the only chance.

[cherdano]

FrancesHinden, on Jul 16 2008, 04:12 AM, said:

As a (very) general rule, the squeeze works when the two menaces are together, the finesse works half the time.

The chance of the two menaces being together is always under 50%, but the exact odds vary depending on the position and the exact nature of the menaces. Simply once an opponent has one of the menaces, he has used up more of his cards and the chance of his having the other is lower.

In your layout, if I give both opponents 6 vacant places (so no indication of shape at all), and assume all seven spades are still outstanding, then the chance of the king of hearts being with the long spades is

spades 4-3: 75.8%, king of hearts with the 4-card suit 40%
spades 5-2: 22.7%, king of hearts with the 5-card suit 20%
spades 6-1: remainder, K of hearts with the long spades 0%

giving a total of 35% for the squeeze

That makes the finesse much much better odds.
I don't know what the chance of singleton HK offside is because that will depend on how many hearts you had between the hands originally.

Usually it's rather closer, because you usually have a bit more information about the vacant places.

No indication about shape at all? Your calculation assumes you can count both opponent's total length in the minor suits to be 7 cards.

[FrancesHinden]

I meant "no indication of spade shape"

[catatonic]

none , except no spade discard ...if they were other than 4-3 there probably have been one

[dburn]

catatonic, on Jul 16 2008, 04:56 AM, said:

you have arrived in 7NT , and had a lead in one of the 2 suits in which you are solid ;
cashing those suits first you arrive at the following ..[both suits break as evenly as possible]

Qx     AKxx
QJT    Ax
A

needless to say , no discard from the suits you still hold

is the vienna coup a better than the 50% of the finesse ? even though unlikely it seems to me that the small chance of dropping a singleton K is added to the 50% of the K being with 4 of my suit ...or am I missing something here

Not really possible to answer this, because there may be a restricted-choice element that has not yet been taken into account (Frances, I'm surprised at you .)

All I know is that one of the opponents led one of the (minor) suits in which I was solid. But if that opponent were South and led from some random collection of low cards in a minor, he might equally have led from some random collection of low cards in hearts if he had one. The fact that he led a minor increases the chance that he has the king of hearts by a factor of... well, who knows? The same sort of reasoning, of course, applies to North.

It is a capital mistake, as someone once observed (no *****), to theorise without data. Who was declarer? What was the actual opening lead?

[catatonic]

tut tut david , you have stolen my next line as below ;btw , the 4spades were in the dummy , and the lead was from 3 middle diamonds

you have now forced me into my arthur conan doyle type line [the dog didn't bark in the night ]; well , she didn't lead a heart , after an auction that in went 2NT , 4C , 4 NT for 3 aces ,7NT

actually , I wonder if I misplayed this ; both minors being solid , I happened to cash the clubs first ;maybe I should have cashed the solid diamonds first as it was lead...presumably the opps would have signalled their distribution; whereas when I cashed the clubs first they could see I was 3-2 [or2-3 ] in the majors

[gnasher]

catatonic, on Jul 17 2008, 12:50 PM, said:

presumably the opps would have signalled their distribution

Where do you find such kind opponents?

[catatonic]

not kind ..it wasn't likely to help me , only them ; suit was solid

[gnasher]

You've just said that if you'd played your suits in a different order they would have signalled their distribution, and that this might have helped you to guess the ending correctly. So, who is likely to be helped by the opponents' distributional signals?

[catatonic]

obviously I wasn't clear ....by playing clubs first I was making the minor suit position fairly clear, playing diamonds first might have made it less clear