[AIexPope]

Bridge-master. Level 1. Problem A5. Solution.

[smerriman]

Without doing the calculations, the probability of dropping the queen is 57.92%, vs the finesse which is 56.22%. Thus the reason for the saying.

[nige1]

AIexPope, on 2017-May-07, 00:44, said:

Is there any way I can add a link to Bridge Master Level1 A-5 please?

Use the URL of the solution,
Click on the link symbol to the right of the smiley in the edit panel, paste the address, and write a description.
Bridge-master. Level 1. Problem A5. Solution.

[AIexPope]

nige1, on 2017-May-07, 01:10, said:

Use the URL of the solution,
Click on the link symbol to the right of the smiley in the edit panel, paste the address, and write a description.
Bridge-master. Level 1. Problem A5. Solution.

Thanks

[AIexPope]

smerriman, on 2017-May-07, 01:08, said:

Without doing the calculations, the probability of dropping the queen is 57.92%, vs the finesse which is 56.22%. Thus the recent for the saying.

Thank you for your very precise answer. Any reference please? curious if 56.22% takes into account singleton Q or Qx onside.

[smerriman]

AIexPope, on 2017-May-07, 01:57, said:

Thank you for your very precise answer. Any reference please? curious if 56.22% takes into account singleton Q or Qx onside.

There's one at the bottom of here.

[AIexPope]

smerriman, on 2017-May-07, 02:13, said:

There's one at the bottom of here.

It looks right for an amateur's eye so I'll change my vote. Thanks.

[gwnn]

8 ever, 9 ever, but I should say that finessing whenever you have any tiny inference in favour of it is one of the easiest and safest ways of feeling like a genius and/or trying to create a swing. Even if the inference is wrong, you only lose about 1% of equity, so it's OK (unless it's an inference in favour of dropping but you mistakenly thought it's in favour of finessing).

However, another issue is that finessing sometimes requires you to risk some defensive ruff crossing from one hand to another, or that using up an entry in a suit gives up on some secondary chances in that suit. It's all hard to quantify but dropping is generally what I do unless I feel like feeling like a genius etc.

[sfi]

Another way to think about it is the idea of vacant spaces.

At the time you have to make the decision, you don't know about the distribution of any of the three side suits, but you do know where all the small hearts are. So LHO has 12 vacant spaces in their hand for the HQ, while RHO only has 11. That means playing the ace wins 12/23 of the time, while finessing wins 11/23.

There's not much in it, but the ace is the right play given what we know about the hand.

(You might think the two spades you've seen from each hand should be taken into account, but all that really tells you is spades don't break 8-1 or 9-0, which doesn't change the odds in any material way here. You can factor in the small hearts because neither hand would play the HQ before a small one, so the two groups of cards can be treated separately.)

[Fluffy]

gwnn, on 2017-May-11, 05:56, said:

8 ever, 9 ever, but I should say that finessing whenever you have any tiny inference in favour of it is one of the easiest and safest ways of feeling like a genius and/or trying to create a swing. Even if the inference is wrong, you only lose about 1% of equity, so it's OK (unless it's an inference in favour of dropping but you mistakenly thought it's in favour of finessing).

However, another issue is that finessing sometimes requires you to risk some defensive ruff crossing from one hand to another, or that using up an entry in a suit gives up on some secondary chances in that suit. It's all hard to quantify but dropping is generally what I do unless I feel like feeling like a genius etc.

I use another rule, if the opponents haven't told you that there are bad breaks ahead by entering the bidding, there is a good chance that it is because there are no bad breaks ahead. So when there is no oposition, it is a good indicator that the split is better than 1%.

[gwnn]

Um I mean that's not really another rule I think​ Fluffy, I mainly meant bidding inferences. If my opps passed throughout, I agree that's a good reason to play for the drop.