[Mbodell]

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It is day 2 of the national 0-10,000 MP pairs. While not the world's strongest field, everyone is at least intermediate+, some better than that. Your opponents are unknowns, but seem to be playing a fairly normal "expert standard" convention card. The opening lead is the ♥3. It is match points so there will likely be a big difference between making 12 tricks and making 13. Your choice?

[manudude03]

The options are finesse at T1 or a squeeze (which works if whoever has the ♥K has 4+ spades. If someone has 4 spades, then they will have 9 vacant spaces compared to 11 for their partner, so that works out to be around 45% for bouncing up with the ace, while the finesse is 50%. I'd finesse unless I knew the opponents didn't lead away from kings (which admitted is quite common at least where I'm from). Also, if the king was offside, they may well have chosen a different spot card to lead.

[phil_20686]

manudude03, on 2014-July-24, 05:41, said:

The options are finesse at T1 or a squeeze (which works if whoever has the ♥K has 4+ spades. If someone has 4 spades, then they will have 9 vacant spaces compared to 11 for their partner, so that works out to be around 45% for bouncing up with the ace, while the finesse is 50%. I'd finesse unless I knew the opponents didn't lead away from kings (which admitted is quite common at least where I'm from). Also, if the king was offside, they may well have chosen a different spot card to lead.

So your maths is wrong, as its basically half of spades being 4-2 or worse, which is < 45%. Think you meant to say its 45% of spades being 4-2 or worse.

But agree with everything else. Finesse clearly better on %, leading away from a K v common among good players vs slam, so if anything small increase over a finesse on a club lead. Also, everyone in 6N who got a minor suit lead will be taking the finesse, there is no need to get cute.

[manudude03]

phil_20686, on 2014-July-24, 06:15, said:

Think you meant to say its 45% of spades being 4-2 or worse.

Yeah, that's what I meant, forgot to multiply in spades being 4-2 to start with .

[whereagles]

A large part of the field will be getting a different lead. When weighting an unlikely major suit squeeze or a finesse, they'll probably finesse.

So I'll do the same. This doesn't seem like a hand to get clever. Some people will be in 7, others in game (lol).

[quiddity]

phil_20686, on 2014-July-24, 06:15, said:

So your maths is wrong, as its basically half of spades being 4-2 or worse, which is < 45%. Think you meant to say its 45% of spades being 4-2 or worse.

But agree with everything else. Finesse clearly better on %, leading away from a K v common among good players vs slam, so if anything small increase over a finesse on a club lead. Also, everyone in 6N who got a minor suit lead will be taking the finesse, there is no need to get cute.

Leading away from a king against a confidently bid 6NT at matchpoints is very common among good players?

[nige1]

manudude03, on 2014-July-24, 05:41, said:

The options are finesse at T1 or a squeeze (which works if whoever has the ♥K has 4+ spades. If someone has 4 spades, then they will have 9 vacant spaces compared to 11 for their partner, so that works out to be around 45% for bouncing up with the ace, while the finesse is 50%. I'd finesse unless I knew the opponents didn't lead away from kings (which admitted is quite common at least where I'm from). Also, if the king was offside, they may well have chosen a different spot card to lead.

phil_20686, on 2014-July-24, 06:15, said:

So your maths is wrong, as its basically half of spades being 4-2 or worse, which is < 45%. Think you meant to say its 45% of spades being 4-2 or worse. But agree with everything else. Finesse clearly better on %, leading away from a K v common among good players vs slam, so if anything small increase over a finesse on a club lead. Also, everyone in 6N who got a minor suit lead will be taking the finesse, there is no need to get cute.

Agree with manudude03 and phil_20686 -- but another tiny quibble. Playing the squeeze, you reduce to this 3-card ending, making when a defender started with ♥K and either ♠QJT or 4+ ♠

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[PhilKing]

Against myself I would play for the squeeze, since there would be a zero % chance of the finesse working.

Seriously, did people even read the auction?

[kenberg]

I also rise. If we just look at teh cards and ignore the lead, I think the odds are about 2 to 1 against the squeeze. A six card suit splts 3-3 about 1/3 of the time (My old copy of Goren says 36%, I suppose this doesn't change with time!).. We need the spades to not split 3-3, so that's 64%, and then we need the heart Q to be with the spade length, a bit less than 50-50.. So the odds are not great.

Still. I cannot imagine myself underleading the ♥K on this auction. I would not do it at imps, and I would not do it at matchpoints. If my left hand opponent has done so, I will take the consequences.

I realize I am saying nothing that has not been said. I'm just casting another vote. And if I am wrong here on this hand, I am still doing the same thing next time. Call me a slow learner.

Added: It was mentioned earlier that some players might be in a different contract. True, but it doesn't matter. I gain a matchpoint from those who stopped in game no matter which heart I play. Same thing for those who are in 6♦. For those who are in a grand, they beat me if they make it and I beat them if they go down, again no matter which heart I play.

So the only issues is how best to make 13 tricks.My job is to gain a matchpoint aganst the pairs where a matchpoint is in play. This means those who are in 6NT. A.k.a. the sane pairs.

[EricK]

whereagles, on 2014-July-24, 09:05, said:

A large part of the field will be getting a different lead. When weighting an unlikely major suit squeeze or a finesse, they'll probably finesse.

So I'll do the same. This doesn't seem like a hand to get clever. Some people will be in 7, others in game (lol).

But these other people haven't had the advantage of getting a ♥ lead which tells them that the King is very likely to be offside - so of course they'll finesse.

Just out of interest, what would you do if you happened to be in 7NT and got a ♥ lead?

[whereagles]

EricK, on 2014-July-26, 11:14, said:

Just out of interest, what would you do if you happened to be in 7NT and got a ♥ lead?

why the ace, of course. Bidding a grand on a finesse is wrong, so you have to play for something else instead

/irony off

[whereagles]

kenberg, on 2014-July-26, 06:45, said:

Still. I cannot imagine myself underleading the ♥K on this auction.

A sneaky LHO might do it. But even those guys refrain from leading from a king into the strong hand, so yeah I guess there's like 95% chance the king is offside.

If LHO knows the ace is in dummy the king underlead is more attractive.

[Fluffy]

I underlead all my kings against slams, but this bidding certainly doesn't ask for it as partner is marked with at most 1 card.

[Mbodell]

So I was interested in what people would decide. Also, I know some int players who want to work on spotting squeezes, and this is a hand where spotting the squeeze should be pretty straight forward (even if evaluating if the squeeze line is the right line is not so starightforward). Here is my analysis and table results:

From my thoughts it is worth considering what to do a priori with no opening lead, and then consider how the opening lead changes that.

So if all I could see was the declarer and dummy and had no insight into opponents shape, then the finesse is 50% 13 tricks, 50% 12 tricks. The squeeze will work when spades split 4-2 or worse and the longer hand has the K, also when QJT of spades with the K, also if there is mis-defense from a 3-3 split where the non-squeezed hand keeps hearts of clubs but not the spades. How likely are these:
spades:
4-2 48%, plus K with the 4 cards, 9/20 of this: 21.6%
5-1 15%, plus K with the 5 cards, 8/20 of this: 6%
6-0 1%, plus K with the 6 cards, 7/20 of this: 0.4%
3-3 36%, of those if QJT is with the K, this works, also if QJx is with the K give me 10% of those for careless pitch from Txx and if QTx is with the K give me 5% for pitch from Jxx. This gives me the following combinations: 1+3*.1+3*.05 = 1.45 of these, there are 20 total, so 1.45/20: 2.6%

Add it all up, with my assumptions about slight chance of pseudo turning into real squeeze and you get about 30.6%.

You also win if the hearts are 7-1 with the stiff K offside, which happens 1/16 of 3%, but only of the times the spade, heart, didn't work. So that might bring us up to 30.7%.

So clearly considering nothing about the lead, the heart finesse is best. But we did get a heart lead. If LHO has the heart K are they more or less likely to lead hearts? I think on this auction, much less likely. To try and figure out a swag at how much less likely I posted this hand on bridgewinners twice from the opening leaders POV. I gave the same auction, same shape, and same hand except once the top 2 hearts are K8 and the other the top 2 hearts are 98. Otherwise the hand is identical (and one of those hands was the actual hand at the table).

The two threads are at http://bridgewinners...ad-problem-432/ and http://bridgewinners...ad-problem-431/ and I posted them 2 days apart to try and make it not quite as clear that they were identical problems (and I posted the one with the K first, since I thought it was more likely to be biased). Just grouping all the non-king heart leads we have that people were only leading a heart from the K 32% of the time. For the hands with no K, people were leading a heart 76% of the time. So just based on the fact that we got a heart lead, the K now rates to be onside only about 29.6% of the time! Onside or not is mostly unaffected on our squeeze analysis (other than the extra 1 in 1000 chance of stiff K off) since the squeeze is automatic and operates against either player if they have the K.

This doesn't fully decide it, obviously, since there could be other shapes that LHO has and those might be more or less likely to lead a heart from no K versus a heart from K. Also, not all heart spots are identical. The ♥3 is 6% of the time the choice from the K but only 4% the choice from the 9 because people choose 4th best or top of 98xxx much more likely. I think that is a smaller sample size issue, and choose to ignore it, but maybe I shouldn't.

At the table I thought for a fair while and decided that underleads of the K were rare on this auction and to play for the squeeze. The K is offside and the person with the K has QJxx of spades. So I made all 13 tricks. +1020 was worth 85% of the MP. +990 would have been 53% of the MP. (+1440 for 97%, +920 for 27%, +490 for 18%, -50 for 8%). Looks like the % is similar in the LM Pairs day 3 where 1020 is 81% for declarer, 990 is 45% (920 is 20%, 490 is 16%, -50 is 9%, 1520 is 97%).

[whereagles]

geeez... what a cook-up for a simple finesse. but ok