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Suit Combinations Contribute a Suit Comination

#41 User is offline   Flame 

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Posted 2005-January-04, 21:47

Yzerman, on Jan 4 2005, 10:31 PM, said:

Yzerman, on Jan 5 2005, 01:49 AM, said:

Here is one that come up 2 times in same day.


hand AQ108x ..... dummy xxx

Suit is trumps, both time IMPs, entries to dummy not a problem ...

a -  1st time - for 4 winners

b -  2nd time - for 5 winners

The "book" says;

4 winners - Low to Q, then low to 10 (when Q holds) - picks up any Kx, Jx, 9x, KJx, K9x, KJ9, 9, J, or K onside and stiff 9 or J offisde and loses only to stiff King offside.

5 winners - Low to 10 then low to Q (assuming 10 holds) - picks up KJx onside.

Where is my "And the winner is..." :) I just need those times when im right to give me more confident if you seen me shaken at the table you would understand.
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#42 User is offline   Flame 

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Posted 2005-January-04, 21:49

HeartA, on Jan 4 2005, 10:34 PM, said:

Yzerman, on Jan 4 2005, 10:31 PM, said:

4 winners - Low to Q, then low to 10 (when Q holds)  -  picks up any Kx, Jx, 9x, KJx, K9x, KJ9, 9, J, or K onside and stiff 9 or J offisde and loses only to stiff King offside.


It losses to KJ doubleton as well.

True, but
KJ is less likely then Jx and K single together. more then 1.5 times better if im not mistaken.
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#43 Guest_Jlall_*

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Posted 2005-January-04, 22:42

fred, on Jan 4 2005, 07:42 PM, said:

KQ10987

32

well lets see.

If you take the first round finesse, you pickup AJxx and Jxxx and Jxx onside (8.48 and 2.43 and 10.17 %). You lose to Axxx onside, or Axx onside, or Ax onside (assuming you are playing low to king then low to queen...(2.83 and 10.17 and 10.17%). So low to the king is a superior start.

Now, lets say it goes low to the king and all duck. You lead up to dummy again, and they duck again. If they would ALWAYS duck with Ax offside, and with Axx onside, then its a pure guess. But if they would always duck Ax offside, that means if they win the ace they MUST have AJ tight (so you should duck it). Now you pickup an additional 3.39 % always. So optimally they should not always duck Ax offside so they can protect themselves when they have AJ tight. I'll let you do the game theory math but essentially some of the time they must be winning with Ax. So the percentage play is now low to the king and low to the queen. Nice combo.
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#44 User is offline   Fluffy 

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Posted 2005-January-05, 02:31

void

AQ108765

Ace first, next the 8, I know hundreds of players who will put J from KJxx over the 8. Anyway in theory as already said is equal.

KQ10987

32

Against our usual opponents low to the K and play for a 1 honnor third onside is the best in practice obviously.

In theory is far more complicated, what if LHO raises with the ACE?, does he have AJXX?, I doubt anyone will make a second roudn finese, but AJXX is actually the holding wich could make you make first round finese to the J, I dunno wich is the theorical best spot, but probably that holding switches wich one is best :).
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#45 User is offline   whereagles 

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Posted 2005-January-05, 03:44

fred, on Jan 5 2005, 02:34 AM, said:

The vast majority of successful tournament players don't know their suit combinations very well

That is very, very true :)
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#46 User is offline   joker_gib 

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Posted 2005-January-05, 06:57

fred, on Jan 4 2005, 07:42 PM, said:


KQ10987

32


There are 32 possibilities for the 5 remaining cards.

Low to the 10 directly works 15 times
Low to the K and then low to the 10 works 15 times

And the winner is ....

Low to the K then low to the Q works 16 times !! ;)

Am I right ?
Alain
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#47 User is offline   Yzerman 

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Posted 2005-January-05, 08:08

How about a few counters to suit combination and/or some frequent positions that may catch people sleeping.

My favorite counter is the following suit combination defense (neat story accompanies this defense) -

Dummy
AJ9x

You
K10x(x)

Although there are many combinations in which a player may play honor under the ace on first play, this is position where King is nice counter.

My partner I were watching a young player and his partner play vs Meckwell in early rounds of the Spingold a few years back. A few of us were at a vantage point where we could see dummy (young dude's partner), declarer's (young dude), and Jeff Meckstroth's hands. We could see from declarers hand and the dummy that declarer had 9 tricks in 3NT once he knock ace in his long suit, but for some reason declarer attack a side suit, 7 card fit, with the above combination. Before the young kid's card hit the table, Jeff Meckstroth had the King on the table, at that point there was MONUMENTAL pause in tempo as the young player realized he just jeopardize his contract. I was absolutely amazed at the table presence, knowledge and experience of Jeff Meckstroth to play the King as a reflex, HE DID NOT HAVE TO THINK AT ALL ABOUT THIS. This was a tremendous learning experience for myself, for I understood much better what makes a world class player.

Some other combinations or positions that are frequent in which many players are caught sleeping;

1 - In trump suit where you are in front of AQ10(x+) in front or where you are behind xxx(x+) and you hold Kx. Playing the K is fairly standard (obviously depending on a few conditions). Most important is when you are behind xxxx with Kx, unblocking the K in case partner have AJx or Q10x in trumps.

2 - ANOTHER FAVORITE - Declarer is playing suit contract in which auction and/or dummy reveals that declarer has many tricks. Early in hand declarer suspiciously cashes an Ace from an "empty" suit and you hold Kx or Qx. Better not get caught sleeping!!!

* I played with partner in tournament few years back, and my partner attempt cash of ace on hand @ trick 2, my LHO (who is many time NABC champ), says aloud to table as the she played the King in this suit, "you are not playing against a novice, but nice try anyway". NOW THAT IS A BRIDGE PLAYER!
MAL
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#48 User is offline   luis 

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Posted 2005-January-05, 12:51

KQT9887
xx

I have this "cached" in my memory... Low to the K, if that holds low to the Q. But if the K/Q is taken with the Ace play the queen next. Restricted choice applies, RHO can't duck the K/Q with AJ doubleton :-)

It's different if you have

KQT98
xxx

For four tricks you play low to the K and then low to the Ten.

Luis
The legend of the black octogon.
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#49 User is offline   han 

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Posted 2005-January-05, 12:51

fred, on Jan 4 2005, 07:42 PM, said:

KQ10987

32

You can afford to lose only 1 trick.

This one is harder than the other combinations that have been posted in this thread so far.

Happy New Year to all!

I have erased this message since I changed my mind after posting :blink:
Please note: I am interested in boring, bog standard, 2/1.

- hrothgar
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#50 User is offline   Rebound 

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Posted 2005-January-05, 16:54

fred, on Jan 4 2005, 08:42 PM, said:

Your next assignment:

KQ10987

32

You can afford to lose only 1 trick.

Well Fred, here's my 2 cents:

First, it doesn't matter what you do in the following cases, 5-0 break, AJx or AJxx offside, singleton A either side. If the J is singleton onside then you know what to do.

Now, low to the 10 right away loses anytime the J is offside but it's not as silly as you may think since most of those cases are already covered above. So, the only relevant ones that fail are AJ, J(x)(x) - 4 cases. Still seems like a bad idea, just not as dumb as it first appears. Note the following: if LHO AJxx you must lead low to the 10 and then low to the 9 but that's only 1 case so we'll assume the first lead is to the king.

If the first lead loses to the A on the right, all other holdings having been eliminated above, the opps holdings will be Jx opposite x or xx opposite J so you must guess. Likewise, you have no problem if LHO goes up A. If the K is allowed to win here's what ya got in the opps hands: Jx - A, Ax - J, AJ - x. Obviously the last holding is trivial since you will know what to do once LHO plays. So it really comes down to a guess: which one has the J and which one has the A? So, another 50-50 shot. I hope I have this right.

Incidentally, it took me a long time to work this out. Really interesting problem, Fred, thanks.

This post has been edited by Rebound: 2005-January-05, 17:02

I'd rather have a bottle in front of me than a frontal lobotomy - but it might improve my bridge.
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#51 User is offline   Rebound 

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Posted 2005-January-05, 17:35

Opps, I dismissed the case where LHO goes up A right away too quickly. Fortunately, my reasoning still holds. The only possible remaining holdings are Jx - x and x - Jx, the others having already been eliminated. So again it's a 50-50 shot whether to play the Q the next time. Oh, and one other, hopefully minor, error. You can succeed with stiff A offside, but again you have to lead low to the 10 then low to the 9. That still doesn't make it worth it I don't think. So I believe I am still correct in essence.
I'd rather have a bottle in front of me than a frontal lobotomy - but it might improve my bridge.
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#52 User is offline   fred 

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Posted 2005-January-05, 19:22

The answer to:

KQ10987

32

A few of you either got this right or came close to getting it right. Well done!

I am making the assumption that the defenders will always defend optimally.

The first problem is whether to play an honor from the dummy on the first round or finesse the 10. This is pretty much a math problem and since some of you did the math already, I am not going to go into it here. Playing an honor from the dummy on the first round is correct.

Now let's assume that this wins the trick and you travel back to you hand to play a 2nd round of the suit with LHO following small again.

At first glance this appears to be a pure guess. Playing the other honor is necessary when LHO started with Axx and playing the 10 is necessary when LHO started with Jxx. The odds of these 2 holdings are exactly the same so it seems that you might as well toss a coin.

Now let's back up for a minute and suppose that RHO had won the first trick with the Ace. This would appear to be a bad play from Ax since RHO could have ducked and given you the guess on the 2nd round that I referred to in the previous paragraph.

However, it would be necessary for RHO to win if he had AJ doubleton since this would be his only chance to win a 2nd trick on defense.

Therefore, it seems reasonable to conclude that if RHO wins the first trick with the Ace you should play him for AJ doubleton because we are assuming optimal defense.

But is that really optimal defense? Suppose that a tricky RHO figures this out and decides to win the first trick at least some of the time from Ax in an attempt to make it look like he has AJ.

The correct strategy for the declarer is to let him get away with this, to play him for AJ, and to go up with the other honor on the 2nd round (thereby failing to win the 5 tricks that are required).

In order to see that this is true, you have to understand something about the basic nature of suit combination problems. The general way to approach these problems is to come up with a set of holdings that the defenders can have for which success is possible regardless of the strategy that the defense chooses to adopt. Several of these sets can be constructed for most suit combinations - the one you are looking for is the set that has the greatest total probabality.

So before you play a single card you should think to yourself: I can come up with a plan that works whenever RHO has Jx or AJ (among other holdings which all cancel out): I will play low to the King and, regardless of whether that loses or not, I will play low to the Queen the second time.

The alternative plan is to play low to the King and, regardless of whether that loses or not, finesse the 10 the second time. This plan works whenever RHO has Ax but it loses to his AJ doubleton.

The odds of Ax and Jx are the same so the first plan is correct because it picks up one additional holding: RHO having AJ.

Do you find the part about "regardless of whether it loses or not" to be strange? Shouldn't the defenders plays impact your strategy?

No! They are not on your side!

Make your plan and stick with it.

I hope that the above explanation was coherant. These concepts are not exactly easy to explain, but I can tell you for sure that I know I am right :P

Fred Gitelman
Bridge Base Inc.
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#53 User is offline   Rebound 

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Posted 2005-January-06, 01:00

I guess I should apologize for my long post since it turned out to be mostly irrelevant and fundamentally flawed. It is indicative of the main problem I have with bridge... the ability to discard the irrelevancies without going thru the complete line of reasoning. Sorry folks.
I'd rather have a bottle in front of me than a frontal lobotomy - but it might improve my bridge.
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#54 User is offline   fred 

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Posted 2005-January-06, 01:32

You didn't do so bad rebound. You did figure out that it was wrong to finesse the 10 on the first round and you figured out that the 2nd round play appears to be a complete guess. I think it shows courage to attempt to solve a different problem in front of 100s of people and that there is absolutely no reason for you to apologize.

Fred Gitelman
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#55 User is offline   mpefritz 

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Posted 2005-January-06, 08:30

More later, but there may be some restricted choice on the spots when looking at the plays when EAST wins the first round with the A, when EAST also has a non-zero probability of playing the A from Ax combinations. Depending on his likelihood of playing the A from Ax, there may be a point at which playing for the AJ is wrong. (my gut say he has to be 75% likely to play A from Ax to not play for the AJ when the ACE is won on the first round)

Note that if you get all spots on the first round and as you lead to the board on the second round, this likelihood of playing the A from Ax by EAST also comes intio play, but there is no RC on the spots as you have seen them all.

fritz
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#56 User is offline   fred 

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Posted 2005-January-06, 09:27

I am not going to do the math, but I am willing to bet (a lot!) that whatever restricted choice inferences existing on RHO's spot card play, they are cancelled out the restricted choice inferences on LHO's plays.

One way to deal with restricted choice is to not even thinka about it and to just enumerate all of the relevant holdings in which each line of play succeeds - the results will always be the same.

Fred Gitelman
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#57 User is offline   Fluffy 

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Posted 2005-January-06, 09:55

Back to the first case I just played a deal in BBO with same kind of guess

KJ9765432

void

Having ot guess wich honnor is singleton :P
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#58 User is offline   Stephen Tu 

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Posted 2005-January-06, 15:03

Quote

Do you find the part about "regardless of whether it loses or not" to be strange? Shouldn't the defenders plays impact your strategy?

No! They are not on your side!


It depends on how well you think you know your opponents. Generally with suit combinations, there is a theoretical best strategy (possibly more than one with equivalent success rate) for declarer that will guarantee him a certain percentage of success against any defense, including the optimal defense. He basically chooses beforehand which suit combinations he will pick up, and ignores falsecarding if it is consistent with one of those holdings. If the defense is sub-optimal, declarer can take an alternate line to take advantage of this, and improve his score. However, if declarer is wrong about the opponents & they are actually defending optimally, he will get a worse score than the theoretical best.

Lately, particularly in pair events against unknown random opponents (at any level less than say at least a Blue Ribbon semi-final), I have started just playing them for being poor players & playing true cards, not randomizing / falsecarding appropriately, and not being good enough to duck when it's right, and my results have improved. I only revert to the theoretical best line against players whom I know and respect their play. Best against good defenders is not best against poor ones!
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#59 User is offline   shanbari 

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Posted 2005-January-07, 13:31

fred, on Jan 5 2005, 08:22 PM, said:

..
Do you find the part about "regardless of whether it loses or not" to be strange? Shouldn't the defenders plays impact your strategy?

No! They are not on your side!

Make your plan and stick with it.

I hope that the above explanation was coherant. These concepts are not exactly easy to explain, but I can tell you for sure that I know I am right B)

Fred Gitelman
Bridge Base Inc.
www.bridgebase.com

it all makes sense, fred,

shan
SHAN
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#60 User is offline   myfish 

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Posted 2005-January-07, 22:48

hi,I want to ask how to play the following suit with 5 tricks

AQ763
K94
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