Author Topic: From the lesson  (Read 2356 times)

kenberg

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From the lesson
« on: November 05, 2018, 10:38:14 PM »
The following hand was from the lesson earlier today. Note the lead of the !H T

http://tinyurl.com/y83wge2g

In the discussion afterward, the correct play was given assuming that the lead was the !D K. It's true that I can still make the hand on the heart lead. I didn't. My question: Should I?

After the lead of the !D K we trust the !D Q to be where it is, after which we do not care where the !H Q is. Just take the !D A at T1, draw trump, play 3 rounds of hearts. As the cards lie,  N wins and let's say he plays the !C J. Up  with the A, lead a !D, S wins the Q, he is endplayed. Similarly if after winning the !h he plays a !D, S wins and is endplayed.

As the cards lie, the same idea works on the heart lead. Win. Draw trump, play a top !H and another !H. No diamonds have been played yet but if N now plays one we go up with the A and lead another.

But: On the lead of the !H T we have no reason to believe S holds both the K and Q of !D.

But But. I am now thinking it is still right to try it. Win the !H, draw trump, top !H and another !H. Say that a !C is returned. Up with the A, the !D A and another !D. As the cards lie this works. But on a different lie N could win the second !D. Then I have to hope that the !C K is right, but trying for the endplay costs nothing. And in this case it works.


So yes, I think that I still should have made it.


Added: In my defense, I did have a plan. I was hoping that the opening lead of the !H T was from T98(x). So the plan was to win the first !H, draw trump, eliminate diamonds, win the second !H, then throw S in by playing the !H 7 to his 8.  Not a completely crazy idea.  It's a matter of deciding, after the opening lead, whether to play S for !H T98(x0 or to play him for !D KQ(xx). Not for the first time nor the last: "I may be wrong but I'll be right someday".

I hope it is clear this is all meant as enthusiasm for, not criticism of,  these hands.
« Last Edit: November 06, 2018, 03:23:16 PM by kenberg »
Ken

jcreech

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Re: From the lesson
« Reply #1 on: November 07, 2018, 09:30:27 PM »
In the context of an Angel Blue set of hands, you are right; the KQ !D should be expected to be in the LHO's hand for the endplay.

In an ordinary game setting, though, I think you need to have the K !D lead in order to take that view.  I have a friend, who playing with Brian Platnick (back when Brian was a junior player), played for a squeeze over a finesse.  When the hand was over, Brian said to play with the percentages.  When the bidding, play, or circumstances indicates that the squeeze is more appropriate, go with the squeeze.  When you don't have that sort of information, go with the finesse.  In other words, I would take the 50% shot over what I consider to be a lesser percentage play.

In this hand, without the extra information of the K !D lead, you would not have a good reason to play LHO for both !D honors.  You might be willing to play for split honors, and hope that LHO will rise for the endplay. But I suspect that would fail against most pairs.

As I look at the hand, I keep wondering things like, would LHO find the unblock if you were to play the K !H first?  If the !D honors were split and LHO rose with the Q, would RHO overtake to lead the !C?

Thank you for sharing this. 
A stairway to nowhere is better than no stairway at all.  -Kehlog Albran

kenberg

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Re: From the lesson
« Reply #2 on: November 08, 2018, 03:06:54 PM »
As with most hands,  there re several options. For one thing I like South's choice of the !H T at T1.  It could go wrong but he knows most of the points are to his right so there is a good chance that he will regret leading the !D K. If dummy had !D Jxx instead of simply Jx I would be very happy to see that K.  At a recent club game I was in 4 !H X on the auction 1 !H - 1NT - 4 !H, doubled no my left, and would have gone down had I not received the favorable lead of a K  with me holding Ax opposite Jxx.  So the heart lead on this hand might have gone wrong, and indeed I can still handle it if I read everything right, but the  !D K  lead would make it easier.

As to percentages it gets tricky. Of course the initial T could be from Tx, but let's suppose it is backed up by at least the 9. This gets us into conditional probability: Given that LHO has both the T and the 9 of hearts, which is more likely, that he also has the 8 of hearts or that he has both the K and Q of diamonds? Phrased that way, the !H 8 is more likely. If we ran a random simulation, dealing out  the 26 cards of the opponents  and looking only at those deals where LHO held both the !H T and the !H 9,  I would expect LHO to hold the !H 8 about twice as often as he held both the !D K and the !D Q.  How heavily to weigh that? I'm not sure.

These are, as you note, prepared hands. So we can start with the basics.  For example:  Finesses never work in prepared hands. So we know where the !H Q is, regardless of what lead conventions they are using.  And yes, I probably agree that in a prepared hand it is  likely that the !D K and Q  lie on my left. But then Arik could have prepared a hand where the !H T, 9 and 8 lie to my left!.  Ok, probably not.  ::)  Anyway, I try to avoid  thinking about the fact the hands have been prepared to illustrate a point  since the right way to play the hand should be the right way to play it regardless of whether they have been prepared.

Side note: Interesting that you mentioned Brian Platnick.  He is married to the mathematician  Bryna Kra ( https://sites.math.northwestern.edu/~kra/ ), which is how I first encountered him. Not that we know each other well, but it's a small world.

Ken