[Hanoi5]

---

♣4 led. Teams.

[suleiman22]

Spoiler

I would play the J♣ from dummy and see if West overtakes. If west does, you only have two other losers in diamonds and you can draw trumps (assuming there is not a 5-0 break) you will have all of your tricks. If west does not, then I would lead a low heart to the A♥ and lead back and again finesse. If East play the K♣ Then you overtake with the A♣ and the Q♣ is a winner. If East does not, play the Q♣. If West does not overtake, you have your tricks. If West does, then you have your game by means of two ♣ and 5 ♠ and ♥ (assuming West does not lead ♦). If West does lead ♦, then you let them take their two tricks and you then draw trumps. However, this is dependent on trumps not being 5-0. Thanks for reading!
Suleiman

[1eyedjack]

Spoiler

I win Ace of Clubs at trick 1, then Ace of Spades, King of Spades , Q of Spades (or marked finesse), Draw a 4th (winning) trump if necessary, then cash 3 rounds of Hearts discarding Diamond. Continue running hearts if they broke 3-3 (discarding remaining Diamond, then Club). If someone shows out on the third Heart, revert to Clubs.

This makes whenever trumps break 3-2 or Singleton J or T with West, and guards against West having led a singleton Club (where a first round Club finesse fails).

I look silly if West started with all the missing Clubs.
I may also look silly if the Club finesse is working but trumps misbehave, although even then I should still be OK if Hearts break 3-3.

[PhilG007]

Spoiler

Assume trumps are breaking 3-2
Finesse the J♣ If it holds,draw 3 rounds of trumps ending in dummy. Cash the Ace ♥
K♥ Q ♥in that order If the suit breaks 3-3 dummy's long ♥ provides discards
for declarers ♦ losers. Repeat the club finesse and cash Ace♣ If clubs break 3-3
declarer makes 13 tricks by way of 5♠tricks 5♥ tricks and 3♣

This post has been edited by barmar: 2013-September-26, 09:02
Reason for edit: put solution in spoiler format, removed unnecessary quote of problem

[billw55]

Spoiler

I fear a singleton club, so I play ♣A and three top trumps. If they break 3-2, I am home free. If not, I run hearts until somebody ruffs, pitching diamonds from hand. Hoping to make via four ♠, four ♥ and two ♣.

[Trumpace]

I don't think this is the right forum for this problem. Give Dummy the heart J, then yes, probably. Even giving the Heart T, it might be a bit too much for this forum.

There might be something obvious, but I find myself trying to do futile computations trying to decide which line is better (go up with CA or finesse on trick 1). It seems like playing the A might be better by about 3%, but don't take my word for it.

[1eyedjack]

 Trumpace, on 2013-September-27, 10:35, said:

It seems like playing the A might be better by about 3%, but don't take my word for it.

Kind of interested to know how you worked that out (right or wrong )

I just went on gut instinct by my gut suggested that it was rather more one-sided.

Part of the problem as I see it is working out how to adjust the a priori odds of West having a singleton Club given that he has chosen to lead one at trick one. I rated it to go up quite dramatically, but I don't think that you can put a number on it scientifically. (If you were playing against GIB you could bet your bottom dollar that he did not lead from the King)

[billw55]

 1eyedjack, on 2013-September-27, 13:45, said:

Part of the problem as I see it is working out how to adjust the a priori odds of West having a singleton Club given that he has chosen to lead one at trick one. I rated it to go up quite dramatically, but I don't think that you can put a number on it scientifically.

I would rather look at it as: how likely is it that I need that finesse? I figure if I hop up with the ace, I am still at least 80% to make 4♠. So to take the hook, I would need to be 80% sure that the king is onside. No way I am that sure, not close.

[Trumpace]

 1eyedjack, on 2013-September-27, 13:45, said:

Kind of interested to know how you worked that out (right or wrong )

I just went on gut instinct by my gut suggested that it was rather more one-sided.

Part of the problem as I see it is working out how to adjust the a priori odds of West having a singleton Club given that he has chosen to lead one at trick one. I rated it to go up quite dramatically, but I don't think that you can put a number on it scientifically. (If you were playing against GIB you could bet your bottom dollar that he did not lead from the King)

I used pavlicek's calculators. I ignored the tendencies of the opp, conditional probabilities etc and went by pure apriori probabilities (i.e ignored a bad spade split affecting club split probabilities etc).

btw, on this hand, isn't an attacking lead called for? After all, there was a 2H bid by dummy (and given the 3S bid, I presume 2H was game forcing, and dummy was fishing for slam).

So underleading the CK is to be expected.

To elaborate on the calculations: we split our calculation in three parts:

1) There is 79% chance that you can pick up the trumps.
Playing the Q loses about 7.5% when you ruff into a club ruff, so that comes to ~5%. So playing the Q makes 74% of the time.

2) There is 17% chance that you have exactly one trump loser.
Playing the Q wins if there is no club ruff and LHO has the CK, slightly less < 50%, so playing Q wins ~8%.

3) 4% of the time you have a 5-0 trump split. I am assuming you go down.

So playing the Q wins roughly 82% of the time.

Playing the A wins when trumps can be picked up(79%) or hearts divide 3-3 (in part 2 above), which is approx 6%. (You can't cater to clubs 3-3 as the club suit is blocked and you won't have entries to hand after CA, three rounds of trump, three round of hearts discarding a diamond, ruffed. A diamond comes back, ruffed, C to K, ruffed, and 4th club is cut off)

So playing the A wins about 85% of the time.

[Trumpace]

 billw55, on 2013-September-27, 14:20, said:

I would rather look at it as: how likely is it that I need that finesse? I figure if I hop up with the ace, I am still at least 80% to make 4♠. So to take the hook, I would need to be 80% sure that the king is onside. No way I am that sure, not close.

Losing the club finesse still gives you that chance, doesn't it? If you don't run into a club ruff, you still have those chances.

A different way to look at it: Say you have a trump loser for sure.

Now playing the A vs the Q basically comes down to hearts 3-3 vs club finesse doesn't it? (You can't cater to 3-3 clubs in the CA line, as clubs will be blocked). Now you can factor in the chances of a club ruff and try to decide. (Of course, there are other factors like misdefence, other minor factors etc which complicates matters)

Of course, playing the A seems to be the more flexible option, and if one cannot be bothered about the details, choosing the more flexible option tends to be correct.

[Fluffy]

 Trumpace, on 2013-September-27, 16:52, said:

I used pavlicek's calculators. I ignored the tendencies of the opp, conditional probabilities etc and went by pure apriori probabilities (i.e ignored a bad spade split affecting club split probabilities etc).

btw, on this hand, isn't an attacking lead called for? After all, there was a 2H bid by dummy (and given the 3S bid, I presume 2H was game forcing, and dummy was fishing for slam).

So underleading the CK is to be expected.

To elaborate on the calculations: we split our calculation in three parts:

1) There is 79% chance that you can pick up the trumps.
Playing the Q loses about 7.5% when you ruff into a club ruff, so that comes to ~5%. So playing the Q makes 74% of the time.

2) There is 17% chance that you have exactly one trump loser.
Playing the Q wins if there is no club ruff and LHO has the CK, slightly less < 50%, so playing Q wins ~8%.

3) 4% of the time you have a 5-0 trump split. I am assuming you go down.

So playing the Q wins roughly 82% of the time.

Playing the A wins when trumps can be picked up(79%) or hearts divide 3-3 (in part 2 above), which is approx 6%. (You can't cater to clubs 3-3 as the club suit is blocked and you won't have entries to hand after CA, three rounds of trump, three round of hearts discarding a diamond, ruffed. A diamond comes back, ruffed, C to K, ruffed, and 4th club is cut off)

So playing the A wins about 85% of the time.

There is an important factor missing: club lead increases the chances of a singleton club on you left, this is something you shouldn't overlook.

[Trumpace]

 Fluffy, on 2013-September-29, 07:21, said:

There is an important factor missing: club lead increases the chances of a singleton club on you left, this is something you shouldn't overlook.

Why? An attacking lead is called for. I would say that increases the chances of CK to your left doesn't it?

btw, I didn't account for many factors... :-)

All I was trying to say is that this forum is unsuitable for this problem.

[billw55]

 Trumpace, on 2013-September-29, 09:37, said:

All I was trying to say is that this forum is unsuitable for this problem.

I'm not sure that is true. Many problems can be analyzed both simply and in depth. I think the B/N lesson on this hand is simply to recognize the risk that the opening lead is a singleton.

Comparing that risk to the chances of making after playing the ace is another level of analysis, perhaps intermediate (?). Your own analysis says that 4♠ makes 85% of the time after rising with the ♣A. Do you think the chance the lead is a singleton is less than 15%?

[Trumpace]

 billw55, on 2013-September-29, 13:12, said:

I'm not sure that is true. Many problems can be analyzed both simply and in depth. I think the B/N lesson on this hand is simply to recognize the risk that the opening lead is a singleton.

Comparing that risk to the chances of making after playing the ace is another level of analysis, perhaps intermediate (?). Your own analysis says that 4♠ makes 85% of the time after rising with the ♣A. Do you think the chance the lead is a singleton is less than 15%?

Yes. I am expecting a minor suit lead on this auction. To me a club lead tells me nothing extra about whether it is a singleton, but in fact seems to increase the chances that the opening leader holds the ♣K.

To make it a B/N problem, without losing the point of the hand, just replace a heart spot with the Jack in the dummy.

I think B/N problems should have a clear cut answer demonstrating the point of the hand.

[1eyedjack]

 Trumpace, on 2013-September-29, 09:37, said:

An attacking lead is called for. I would say that increases the chances of CK to your left doesn't it?

I wouldn't like to put a number on it, but there may be an application of restricted choice on lead at play here.
If he is minded to lead a singleton, he is much more likely to have a singleton Club than a singleton Diamond.
If he is minded to lead from an honour holding, he is about as likely to lead from a Diamond as from a Club.
Combining these, I think that you should discount to a degree our enthusiasm for expecting him to lead away from Club King.
Perhaps not by as much as I originally gut felt.

[Trumpace]

 1eyedjack, on 2013-September-30, 00:53, said:

I wouldn't like to put a number on it, but there may be an application of restricted choice on lead at play here.
If he is minded to lead a singleton, he is much more likely to have a singleton Club than a singleton Diamond.
If he is minded to lead from an honour holding, he is about as likely to lead from a Diamond as from a Club.
Combining these, I think that you should discount to a degree our enthusiasm for expecting him to lead away from Club King.
Perhaps not by as much as I originally gut felt.

Yes, restricted choice is what I was thinking when I was talking about chances of club lead _probably_ increasing chances of CK. It is your statement about a diamond lead being as likely as a club lead (from honour holding) and restricted choice which increases the chances of a club lead indicating a holding of CK. But there are other issues, like from DAxxx or DJxxx would LHO lead a diamond etc.

I was not claiming it is overwhelming or anything, or even confident that it actually increases the chances of LHO holding CK. One could do the math by applying Bayes' formula and get an approximate figure, but that is not my point.

All this calculation business was just to make the point that it is not clear cut to play the A, and I am pretty sure there is a lot not taken into account (some of which cannot be quantified even, and frankly I think trying to do all these computations is pointless at the table).

I agree with the A play, not because it seems clear cut (or x% better), but because it seems to be the more flexible play: you stay alive longer if you run into bad breaks.

[billw55]

 billw55, on 2013-September-29, 13:12, said:

Do you think the chance the lead is a singleton is less than 15%?

 Trumpace, on 2013-September-29, 14:27, said:

Yes.

Obviously we disagree.

[Trumpace]

 billw55, on 2013-September-30, 07:25, said:

Obviously we disagree.

Obviously.

I am curious. The apriori probability is ~7% (with minor variations restricting diamond lengths with east/west).

Are you thinking the fact that a club was the opening lead more than doubles that? What lead were you expecting?

[broze]

I pity an N/B reading some of these N/B threads.

[billw55]

 Trumpace, on 2013-October-04, 00:28, said:

Obviously.

I am curious. The apriori probability is ~7% (with minor variations restricting diamond lengths with east/west).

Are you thinking the fact that a club was the opening lead more than doubles that? What lead were you expecting?

Yes.

I was expecting his most attractive lead from a minor suit. A singleton is a very attractive lead. Was it Garozzo who said "if I didn't lead it, it's not a singleton"?

In fairness, I must consider that the appearance of the hand on the forum has biased my perception. Particularly the B-N forum. Hanoi is not scatterbrained, he must have posted it here for a reason. Have I overemphasized the simple solution because of that? Perhaps.