[thepossum]

Hi all

Any chance of improving the chance of making the right call on the Queen of clubs in this unlikely slam in an MPs tourney. I couldnt find a way to improve on 50:50 and missed the unlikely doubleton drop. Please no comments on the choice of a grand. I was aiming for an unlikely top expecting most people to be in 6S. As it turned out most people were only in 4S and 6S would have scored well. One table made 4+3. Sadly I ended up equal bottom on 7-1 rather than a glorious 100%

regards P

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[Cyberyeti]

Well you can find out E is most likely 3712, but I don't see why you shouldn't finesse.

You probably only went -1 because W mistakenly discarded a club rather than a heart on the ace of trumps (you may be able to recover via something similar to what is below)

The end position you need to engineer to make 7 is:

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And now you play ♠K and you know you've squeezed W and can make the contract, but are not sure exactly how. Clubs are 4-2 so either the finesse or the drop works, but that doesn't solve the issue of the 4th club loser or diamond loser in dummy. What you've executed is a ruffing squeeze. Either E pitches a diamond and if the J♣ is an entry, you can ruff the diamonds good, or he pitches a club, and you can establish the 4th club with a diamond ruff entry to hand to cash the 4th one if you drop the Q.

I don't see any reason to not go with the odds for the finesse over the drop. If clubs are 4-2, the guy with 4 is twice as likely to hold the Q.

[thepossum]

Thanks

[Tramticket]

thepossum, on 2019-April-21, 23:59, said:

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Was I imagining it yesterday? Or did you initially present this as a play problem with the East/West cards hidden?

By the time I had worked out my solution, the post appeared to have changed. Anyway, I would have played to set up long diamonds for two club discards. It won't work if (as we now discover), diamonds are 5-1 but I think that it will work against most 3-3 and 4-2 diamond breaks. I am envisioning something like this:

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There are just enough entries to set up and emjoy the long diamonds.

[thepossum]

Hi Tram

Thanks for the response. I did originally post it as a play problem but thought it simpler to post the hand and the way I had played it rather than trying to explain the leads, plays and discards. I felt the original post was very untidy and unclear and thought better to put up a clearer post

Thanks for the response

I figured it was probably impossible or unlikely to work out a play. I assume the person who made 13 tricks isnt used to playing probabilities with drops and finesses.

regards P

[wuudturner]

I see 3 main possibilities. Set up the diamonds, a squeeze against West in the minors, or 3-3 clubs, with Qxx onside. The latter is not going to be common. Even if we ignore the question of East having longer hearts, 3-3 clubs are 35.5%, half of the time the queen will be in the West.

Setting up the diamonds is possible, if you maintain sufficient entries to dummy. All that takes is 3-3 diamonds, or 4-2. If they are 2-4, with East having the length, then you have potential problems, as you need to set them up while using trump entries to dummy. You would then be worried about West overruffing.

Anyway, you win the heart king with the ace. (Noting that East did not play the queen.) Then immediately, diamond to the ace, and a low one back. Assume East plays a low heart there. (Note on the defense, even if you could safely have discarded a black card on a red suit, it is often a good idea to pitch red on red. I have occasionally seen an opponent not watch what was happening carefully, and miss that you did not follow suit.) Regardless, ruff the diamond low, and take stock. This tell you a lot about the shape of the defenders hands. Diamonds were 5-1. I would initially presume that East has 6 hearts for the preempt, although 7 is possible. In that case, hearts are 4-6 or 3-7.

Setting up the diamonds is no longer possible. But since West is known to have the diamond honors, then a simple squeeze in the minors against West is now looking like a roughly 50% play. You need to draw trumps, and ruff the heart in dummy first though. This will give you a great deal of information about the hands.

Ruff the heart jack (I expect that West will cover your jack with the queen), then cash the trump ace, then 10 to the king and queen. On the second and third rounds of trumps, West will throw a low heart and a diamond.

You now know that West was originally 1=3=5=4, or 1=4=5=3 shape. East was respectively 3712 or 3613.

What do you know about the points? East has shown by the 2♡ bid 4-9 HCP. Not total points, which for the bots include distribution, but 4321 HCP. But you have seen the spade jack, and the heart king, so East does not need to hold the club queen for the 2♡ bid.

Can you make the contract if East has Qxx in clubs? It appears not, so you don't worry about that case. You essentially need East to have Qx in clubs, or xx, or xxx. If you can find a line that caters to all three cases, this is your best chance. If you cannot find a line that handles everything, then look for one that caters to the most probable subset of those hands. In that case, you will be playing for West to have the club queen.

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At trick 8, you know that West has exactly 2 diamonds remaining (the K9), and no hearts, so 4 clubs. That gives East a doubleton club. If you were going to play anybody for the club queen, it would be West, with 4-2 odds on that bet. There are two cases remaining to cater for, the clubs sitting Qxxx opposite xx, or xxxx opposite Qx in the E-W hands.

At the end here, it helps to know who you are playing. If these are bot opponents, then there is a little trick you can rely on, a bug in the bot programming. You know that East has 2 cards remaining. Does East have Qx or xx? If you cash the ace, then East can see the KJ remaining in dummy. If East had the Qx, then it will play randomly from those two cards, because it assumes that you will be smart enough to drop the queen if it plays low. As such, the Q and the x are equal cards as far as a bot is concerned when you cash the ace. So if you cash the ace, 50% of the time, East will drop the queen if it has Qx. (This is a known behavior of the bots, though I do not know if they have found and fixed this quirk in the bot programming yet.)

Against human opponents, I'd probably just take the 2-1 odds, and play West for the queen. Against bot opps, I'd cash the club ace, hoping to get lucky in case East does have the queen of clubs. If a bot East does not play the queen under my club ace, I'd play West for that card.

[thepossum]

Thx Wuudturner

regards P

[nige1]

Thank you for the instructive analysis, WuudTurner, Fascinating insight into Bot play.

If you cash ♣A at trick 8 or 9 and RHO drops the ♣Q, then the penultimate trump catches LHO in a trump-squeeze
- if LHO comes down to one ♦, then you cross to ♣J and ruff a ♦, leaving dummy high.
- if LHO keeps 2 ♦s, then you cash dummy's ♣s and ruff a ♦, to enjoy the last ♣.

If RHO plays low on ♣A, then you can still play this trump-squeeze (probably taking the ♣ finesse).

Had RHO turned up with 8 (instead of 7) ♥s, then you could claim after cashing ♣A

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