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Play for drop or finesse?

#1 User is offline   Dinarius 

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Posted 2020-February-02, 13:06

In 6♠️ you hold 8,3 opposite A,K,J,7,2, ♣️.

You must make 3 ♣️ tricks to make the slam. Do you play for the drop or finesse?

You have no clues whatsoever.

D.
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#2 User is offline   mikeh 

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Posted 2020-February-02, 14:07

Well, without the rest of the hand,, I truly have no clue. We’re in spades, and this is our club suit. Do I have the trumps and the entries to play AK and ruff one? If so, then I win on all 3-3 breaks and all doubleton or stiff queens. The finesse, on the other hand, wins on only half of the 3-3 breaks, all of the stiff queens (assuming I make the correct play of cashing a high club first) and half the doubletons. Of course, the hook wins against Qxxx(x) onside, but it is still the inferior play.

And if I can ruff two clubs, then that is overwhelming best.

However, if I cannot ruff any clubs, playing for the drop is very much inferior. It wins only against Qx offside and loses to Qxx(x)(x) onside. The Qxx onside is itself more likely than Qx offside. It’s not even close.

This is so basic that I suspect the Qx was offside and declarer was wrongly criticized for finessing.
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#3 User is offline   DozyDom 

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Posted 2020-February-02, 14:32

I'm 100% certain that I have multiple clues available which will help me. The most obvious two, as mikeh points out, are how many trumps do I have to ruff with, and how many entries to the hand with clubs do I have.
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#4 User is offline   Dinarius 

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Posted 2020-February-02, 14:45

Should have said you have total access to both hands and can ruff all you like.

So, I presume that A, K, and two ruffs, if necessary, are overwhelming favourite to playing the finesse. Which is what I would have thought.

Thanks.

D.
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#5 User is offline   mikeh 

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Posted 2020-February-02, 15:30

View PostDinarius, on 2020-February-02, 14:45, said:

Should have said you have total access to both hands and can ruff all you like.

So, I presume that A, K, and two ruffs, if necessary, are overwhelming favourite to playing the finesse. Which is what I would have thought.

Thanks.

D.

You can work it out with the most minimal of thinking. The only time the Queen doesn’t ruff out are if the suit is 5-1 or 6-0. If 6-0 onside, you find this out when you cash a top club, hopefully after pulling trump, and have an easy finesse. If 6-0 offside, no line works. If 5-1 offside, no line works. So: the only meaningful case is Qxxxx onside. Compare that to Qx, Qxx or Qxxx offside, where finessing loses and ruffing wins. There are only 5 Qxxxx onside hands. There are 5Qx offside hands, and far more Qxx(x) offside holdings.

This way of thinking may seem difficult but, with some practice, becomes almost intuitive
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#6 User is offline   Dinarius 

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Posted 2020-February-03, 02:21

Thanks.

One last thing...

Let’s say the suit is 8,7, opposite A,K,J,2.

I.e. the long hand has one ♣️ less.

Which is favourite now, ruff out Q or finesse?

D.
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#7 User is offline   AL78 

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Posted 2020-February-03, 02:48

View PostDinarius, on 2020-February-03, 02:21, said:

Thanks.

One last thing...

Let’s say the suit is 8,7, opposite A,K,J,2.

I.e. the long hand has one ♣️ less.

Which is favourite now, ruff out Q or finesse?

D.


The official encyclopedia of bridge surprisingly doesn't have that combination, but it does say for AKJT9 opposite x, finesse the jack, so I would presume the best line in your layout is to cash a high honor then finesse. This is ever so slightly more than 50% as it works when the queen is onside or stiff queen offside.
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#8 User is offline   johnu 

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Posted 2020-February-03, 03:38

View PostDinarius, on 2020-February-03, 02:21, said:

Thanks.

One last thing...

Let’s say the suit is 8,7, opposite A,K,J,2.

I.e. the long hand has one ♣️ less.

Which is favourite now, ruff out Q or finesse?

D.

Assuming you know absolutely nothing about the rest of the defenders hands, the calculation is very simple. If you have the entries, you should cash a high honor in case the queen is singleton.

If the suit breaks 4-3, you can only ruff out the queen if it is in the 3 card break, which is 3/7. A finesse if 50%

If the suit breaks 5-2, you can only ruff out the queen if it is in the 2 card break. which is 2/7. A finesse if 50%

If the suit breaks 6-1, you can cash a high honor and drop the queen. You can never ruff out the queen if it doesn't drop on the 1st round.
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#9 User is offline   Tramticket 

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Posted 2020-February-03, 03:53

View PostDinarius, on 2020-February-03, 02:21, said:

Thanks.

One last thing...

Let’s say the suit is 8,7, opposite A,K,J,2.

I.e. the long hand has one ♣️ less.

Which is favourite now, ruff out Q or finesse?

D.


Consider the cases where RHO has more clubs than LHO: in each case you succeed if the queen is on your left. (e.g. the clubs are distributed 3-4: the finesse will work if LHO has the Q and fail if RHO has the Q. Playing for the drop will also work if LHO has the Q and fail if RHO has the Q).

Now consider the cases where LHO has more clubs than RHO. Now the odds of LHO having the Q are greater than 50%. Taking the finesse succeeds when LHO has the Q, playing for the drop succeeds when RHO has the Q. It is easy to see that in this case the finesse is the better option.

The actual odds are: Finesse: 50% chance of success; playing for the drop: 36.6% chance of success.
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#10 User is offline   sfi 

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Posted 2020-February-03, 04:38

An even simpler way to see the same thing is that playing for the drop wins when the queen is in the hand with short clubs, which happens less than half the time (since the short hand has fewer cards in that suit). Finessing is the superior play since it is a 50% chance to win.
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#11 User is offline   Cyberyeti 

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Posted 2020-February-03, 05:12

I presume you mean you need 3 club tricks WITHOUT LOSING ONE, as that changes the odds (you're sorted as soon as the guy in front follows to the second one if you finesse if you can afford to lose one).
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#12 User is offline   Dinarius 

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Posted 2020-February-03, 09:59

View PostCyberyeti, on 2020-February-03, 05:12, said:

I presume you mean you need 3 club tricks WITHOUT LOSING ONE, as that changes the odds (you're sorted as soon as the guy in front follows to the second one if you finesse if you can afford to lose one).


But, even if you can afford to lose a ♣️, playing small/small is the same a A,K, small ruff, right?

Anyway, I was only in 4♠️. The other team were in 6♠️. The ♣️ holding was A,K,J,x opposite x,x.

He didn’t finesse. He played A,K, ruff and the Q♣️ fell to the right of the A,K. I.e. the finesse would have lost.

Such is life.

D.
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#13 User is offline   Cyberyeti 

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Posted 2020-February-03, 10:08

View PostDinarius, on 2020-February-03, 09:59, said:

But, even if you can afford to lose a ♣️, playing small/small is the same a A,K, small ruff, right?

Anyway, I was only in 4♠️. The other team were in 6♠️. The ♣️ holding was A,K,J,x opposite x,x.

He didn’t finesse. He played A,K, ruff and the Q♣️ fell to the right of the A,K. I.e. the finesse would have lost.

Such is life.

D.


No, if you need 3 tricks and can afford to lose one in the scenario where you had a 5:2 fit, you cash the ace then finesse. If the finesse loses with LHO following, you're there anyway as a ruff establishes the 5th card, and you now get home if they're 5:1 onside, nothing helps if they're 5:1 with the Q in the 5 or 6:0 offside.

I just realised there is an exception if the 9 or 10 drops from LHO under the A and you can afford to lose one, now you can run the 8 on the second round if LHO shows out, and you can utilise the power of dummy's 7 to take a ruffing finesse if RHO has 5.
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#14 User is offline   Dinarius 

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Posted 2020-February-03, 10:18

View PostCyberyeti, on 2020-February-03, 10:08, said:

No, if you need 3 tricks and can afford to lose one in the scenario where you had a 5:2 fit, you cash the ace then finesse. If the finesse loses with LHO following, you're there anyway as a ruff establishes the 5th card, and you now get home if they're 5:1 onside, nothing helps if they're 5:1 with the Q in the 5 or 6:0 offside.

I just realised there is an exception if the 9 or 10 drops from LHO under the A and you can afford to lose one, now you can run the 8 on the second round if LHO shows out, and you can utilise the power of dummy's 7 to take a ruffing finesse if RHO has 5.


Ok. I thought you were referring to 4/2 fit, which was the case in the actual hand.

Thanks.

D.
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#15 User is offline   Cyberyeti 

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Posted 2020-February-03, 10:32

View PostDinarius, on 2020-February-03, 10:18, said:

Ok. I thought you were referring to 4/2 fit, which was the case in the actual hand.

Thanks.

D.


The OP said AKJ72/83
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#16 User is offline   Dinarius 

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Posted 2020-February-03, 11:00

View PostCyberyeti, on 2020-February-03, 10:32, said:

The OP said AKJ72/83


Yes.

And I also asked about that actual 4/2 holding, which you replied to three posts above.

But, you mustn't have noticed I'd changed it to 4/2.

Thanks.

D.
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#17 User is offline   ruleof15 

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Posted 2020-February-03, 11:10

View PostDinarius, on 2020-February-02, 13:06, said:

In 6♠️ you hold 8,3 opposite A,K,J,7,2, ♣️.

You must make 3 ♣️ tricks to make the slam. Do you play for the drop or finesse?

You have no clues whatsoever.

D.

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#18 User is offline   Cyberyeti 

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Posted 2020-February-03, 11:18

View PostDinarius, on 2020-February-03, 11:00, said:

Yes.

And I also asked about that actual 4/2 holding, which you replied to three posts above.

But, you mustn't have noticed I'd changed it to 4/2.

Thanks.

D.


The interesting one is AKJ7 opposite 83 where you can afford to lose one.

4-2 where it's AKJ3 opposite 42 is easy. the drop is 1/7 of the 6-1s, 2/7 of the 5-2s, 3/7 of the 4-3s so is <50% by a lot, the 2nd round finesse is 50% + stiff Q offside.

AKJ7 opposite 8x, if you hook the 7 then hook the J, you additionally win against 109xx/Qxx.
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#19 User is offline   ruleof15 

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Posted 2020-February-03, 11:57

Assuming transportation is not a problem. After pulling trumps,lead 3 clubs and finesse the J. If it win your problems are over. This protects against a 6-0 and 5-1 break with the J on side. If it loses, win the return and lead the 8, win the A and ruff a C. This wins against all 4-2 (48%) and 3-3 (35%) breaks. This is about an 86+% for 3 tricks.






































..............................++++++++++++++++++Back to hand an
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#20 User is offline   Dinarius 

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Posted 2020-February-03, 12:35

View PostCyberyeti, on 2020-February-03, 11:18, said:

The interesting one is AKJ7 opposite 83 where you can afford to lose one.

4-2 where it's AKJ3 opposite 42 is easy. the drop is 1/7 of the 6-1s, 2/7 of the 5-2s, 3/7 of the 4-3s so is <50% by a lot, the 2nd round finesse is 50% + stiff Q offside.

AKJ7 opposite 8x, if you hook the 7 then hook the J, you additionally win against 109xx/Qxx.


Ok.

With AKJx opposite xx....

So, cashing a top Club and then finessing J is a shade over 50%. While cashing AK and ruffing the x is always less than 50%.

What I would have thought.

Thanks.

D.
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