Cold game at imps

[gnasher]

With any inferences about the lead, I'd have about a 45% chance of gaining two overtricks, and about a 15% chance of going down. The singleton is in dummy's suit, and he seems to have had an attractive club holding, so leading the singelton isn't automatic. I'll guess that he'd lead his singleton 2/3 of the time.

 

That gives me:

- A 5% chance of going down, for a loss of 12 IMPs

- A 45% chance of gaining 2 IMPs

 

In a long match without VPs it would be worth the risk. In a Swiss match which we expect to win, with the barking mad ACBL 30-VP scale, it wouldn't be a good idea.

 

Suppose that without this board we're 5 IMPs up. We're already winning 21-9. and we stand to win 1 VP or lose 13 VPs. It would be best to play safe for the contract.

 

Now suppose that without this board we're 10 IMPs up. Now we stand to gain 1 or lose 8, so playing for the overtricks is about evens in absolute terms. However, 10 IMPs is enough for 23-7, which may well be enough to win the event. So it's still probably right to play safe.

[jdonn]

Did you factor that the singleton might be the king and it would really be 12%, or was that included? Then instead of being right 9 times out of 10 it would be more than 11 times out of 12.

 

And seeing below which is also true, if they get their ruff even half the time, you will gain about 24 times for every 1 time you lose....

[PhantomSac]

With any inferences about the lead, I'd have about a 45% chance of gaining two overtricks, and about a 15% chance of going down.  The singleton is in dummy's suit, and he seems to have had an attractive club holding, so leading the singelton isn't automatic.  I'll guess that he'd lead his singleton 2/3 of the time.

 

That gives me:

- A 5% chance of going down, for a loss of 12 IMPs

- A 45% chance of gaining 2 IMPs

This seems to imply that they will get their ruff 100 % of the time when it's available. That seems really high to me. I'd guess it's closer to 0 % than 100 % tbh. They won't ever be able to read the count because we have the 2.

 

IF LHO has 1 spade and 3 hearts and diamonds are not 3-3 then:

 

If RHO has Hx of diamonds they'll go diamond diamond probably.

If LHO has Hx of diamonds, the defense may block the suit or go wrong.

If RHO Has Kxx of diamonds, LHOs second diamond play may be the ace.

 

etc etc. For RHO to be on lead on the 2nd diamond already takes a fair amount. Of course LHO should try to induce this, and he might, but he might not. Even if he does, RHO might go wrong thinking I cannot have 3 spades and 6 hearts and play this way.

 

It's possible RHO will think deeply about it and realize my line is bad with 2641 (why pitch a diamond esp before I know trumps are 2-2), but that requires deeper thinking than how can i give them this opportunity etc etc.

 

My estimate of them getting the ruff was like 10 % heh, but 100 % seems like a real overbid.

[pooltuna]

[hv=n=saqj7xht97dxxxcax&s=s982hakqj86dqxxck]133|200|Scoring: IMP[/hv]

 

1H-1S-2H-4H.

 

CQ lead.

You win the king, heart to dummy, cash a club pitching a diamond, and lead a heart to the ace, RHO shows out.

 

You are playing swiss teams, it's the last match, opps are average plus but not amazing. They play standard leads and carding

 

You have 122 VPs, they have 119 VPs, there is another team who is good with 118 VPs playing another team that is good. You are using a 30 VP ACBL scale.

 

How do you proceed?

yeah it is probably safe enough to leave a trump outstanding so you have an entry to your hand to retake the ♠ finesse. What usually happens to me is that holding KTxx of ♠ RHO wins the first finesse and a ♠ accidently falls out of his hand and he feels obligated to lead it :)

[gnasher]

Did you factor that the singleton might be the king and it would really be 12%, or was that included?

I'd roughly taken account of that, by assuming that the chance of a singleton king would be roughly balanced by the difference in vacant spaces.

 

I've now checked that using Richard Pavlicek's calculator, and found that a 1=4 break is 18.8%. 4/5 of 18.8% is, fortuitously, 15.04%.

[jdonn]

You are amazing. So then by my random 50% estimate of them getting the defense right if the finesse loses, EV of going for it is .45*2 - .025*12 = +.6 imps, but ignoring the cases where they break even it's +1.26 imps. Or did I mess up?

[gnasher]

This seems to imply that they will get their ruff 100 % of the time when it's available. That seems really high to me. I'd guess it's closer to 0 % than 100 % tbh. They won't ever be able to read the count because we have the 2.

 

 

I suppose it depends on the opponents. To have got to where they are, presumably they're playing better than they usually do, and they have more incentive than usual to concentrate.

 

They both know that you can't have ♦A or K - that would make you too strong for 2♥. Also, if RHO is paying attention he'll already be wondering why you left a trump undrawn. He might play you for 2731, but even then a low diamond is as good as a high one.

 

IF LHO has 1 spade and 3 hearts and diamonds are not 3-3 then:

 

If RHO has Hx of diamonds they'll go diamond diamond probably.

If LHO has Hx of diamonds, the defense may block the suit or go wrong.

If RHO Has Kxx of diamonds, LHOs second diamond play may be the ace.

They started with 7 diamonds, not 6. LHO's likely shapes are 1345 and 1354, so there's no obvious reason for RHO to switch to an honour.

 

For RHO to be on lead on the 2nd diamond already takes a fair amount. Of course LHO should try to induce this, and he might, but he might not

LHO's the one looking at a trump and a spade void, isn't he? I think he would always lead a low one back after winning the first diamond cheaply.

[PhantomSac]

Ya youre right they have 7 diamonds so they would need to be 5-2 for the diamonds to block which is not that likely (since LHO won't have 2 and a stiff spade very often).