Gibs throwing tricks

[toastlots]

I have commented upon the issue of GIBs throwing tricks before, but it still amazes me that they still do it.

 

We are sitting there in 3NT with 9 clubs between us with the ace in his hand and the king in mine.

 

The other 4 clubs are fortunately (and uncharactoristickly)split 2-2. My GIB partner does not know this of course.

 

He leads out a club from my dummy hand and then.......does not use his ace, but lays a low club so the trick is taken by ops with the queen!!

 

Sorry, I am not an expert and might be missing something really clever here, but is that stupid or what?

 

Even if the clubs were split say 3-1, he can always get the lead back again quickly so using both ace and king first to take out at least 2-3 clubs would in my view have been fine.

 

We still got contract, but the entire room got 3+ 2 and we therefore got a -score, unbelievable!

[1eyedjack]

You will be aware that there are more than one standard of GIB available for playing on BBO. Potentially either 1, 2 or 3 versions depending on whether you are playing in a robot tourney, or which standard between the basic and advanced robots you have rented when playing in the Main Bridge Club, and whether you are using the Windows downloaded client or using the Web based interface.

 

I would not be in a position to answer your question, but any answer that you receive will be better informed if you stated the environment with respect to the above factors. It would also help them to reproduce and analyse the error if you post the full hand.

[1eyedjack]

[hv=lin=pn|~~R1259ps2,~~R2203acu,Toastlots,~~R2603uk3|st%7C%7Cmd%7C4S9KH46TAD38TAC48A%2CS56H2357D469QKC5Q%2CS38JQH8KDJC279TJK%2C%7Crh%7C%7Cah%7CBoard%2010%7Csv%7Cb%7Cmb%7Cp%7Cmb%7C1N%7Can%7Cnotrump%20opener.%20Could%20have%205M.%20--%202-5%20C%3B%202-5%20D%3B%202-5%20H%3B%202-5%20S%3B%2015-17%20HCP%3B%2018-%20tot%7Cmb%7Cp%7Cmb%7C2C%7Can%7CStayman%20--%20%20%7Cmb%7Cp%7Cmb%7C2H%7Can%7C2-5%20C%3B%202-5%20D%3B%204-5%20H%3B%202-5%20S%3B%2015-17%20HCP%3B%2018-%20total%20points%7Cmb%7Cp%7Cmb%7C2S%7Can%7COther%20major%20--%209-%20HCP%3B%209%2B%20total%20points%7Cmb%7Cp%7Cmb%7C2N%7Can%7C2-5%20C%3B%202-5%20D%3B%204-5%20H%3B%202-3%20S%3B%2015%2B%20HCP%3B%2015-%20total%20points%7Cmb%7Cp%7Cmb%7C3C%7Can%7C4%2B%20C%3B%203-%20H%3B%209-%20HCP%3B%2010%2B%20total%20points%7Cmb%7Cp%7Cmb%7C3N%7Can%7C2-5%20C%3B%202-5%20D%3B%204-5%20H%3B%202-3%20S%3B%2015%2B%20HCP%3B%2015-%20total%20points%3B%207%2B%20relay%20points%7Cmb%7Cp%7Cmb%7Cp%7Cmb%7Cp%7Cpc%7CD6%7Cpc%7CDJ%7Cpc%7CD2%7Cpc%7CD8%7Cpc%7CC7%7Cpc%7CC6%7Cpc%7CC4%7Cpc%7CCQ%7Cpc%7CDK%7Cpc%7CC2%7Cpc%7CD7%7Cpc%7CD3%7Cpc%7CD4%7Cpc%7CS3%7Cpc%7CD5%7Cpc%7CDT%7Cpc%7CH4%7Cpc%7CH3%7Cpc%7CHK%7Cpc%7CH9%7Cpc%7CCK%7Cpc%7CC3%7Cpc%7CCA%7Cpc%7CC5%7Cpc%7CC8%7Cpc%7CS6%7Cpc%7CCJ%7Cpc%7CS2%7Cpc%7CCT%7Cpc%7CS7%7Cpc%7CH6%7Cpc%7CH7%7Cpc%7CC9%7Cpc%7CST%7Cpc%7CHT%7Cpc%7CH5%7Cpc%7CSQ%7Cpc%7CS4%7Cpc%7CSK%7Cpc%7CS5%7Cpc%7CS9%7Cpc%7CH2%7Cpc%7CS8%7Cpc%7CSA%7Cpc%7CHQ%7Cpc%7CHA%7Cpc%7CDQ%7Cpc%7CH8%7Cpc%7CDA%7Cpc%7CD9%7Cpc%7CSJ%7Cpc%7CHJ%7C]400|300[/hv]

 

Scoring is IMP

 

I am not saying that GIB played it right (not really thought enough about it) but it was not an outrageous line.

 

The contract is not in danger whatever he does in ♣, so we are only talking maximising expected overtricks

 

If he loses a ♣ trick to East and then gets a ♦ through while the ♠A is still missing, then he only has 9 sure tricks (5 x ♣, 2 x ♦ and 2 x ♥)

If he loses a ♣ trick to West, who is marked with both of the missing ♦KQ, then West cannot profitably continue ♦, while if he puts East in with ♠A to lead ♦, in the process it sets up ♠ tricks for overtricks.(Or you have time to attack ♠ yourself)

 

PS not relevant to the thread but I think that you are a bit strong for 2♠, and you may be a tad fortunate that partner did not leave you in 3♣

[ahydra]

I really loved the OP's spelling of "uncharacteristically". :)

 

1eyedjack's analysis is good, but let's go deeper. Taking the finesse into West as opposed to playing for the drop loses to Q or Qx with West but gains when East has Qxx or Qxxx. What are the odds?

 

3-1 split = 49.7%, of which there are 8 combinations, one of which is singleton Q with West, so 6.2%

2-2 split = 40.7%, of which there are 6 combinations, three of which have Qx with West, so 20.3%

 

vs

3-1 split = 49.7%, of which there are 8 combinations, three of which have Qxx with East, so 18.6%

4-0 split = 9.6%, of which there are 2 combinations, one of which is Qxxx with East, so 4.8%

 

So to play the drop is slightly better: it gains 26.5% to 23.4% i.e. 0.031 more overtricks on average.

 

What about playing the K first, then finessing? Now you pick up the singleton Q with West (but can't pick up Qxxx in East), so the finesse improves to 24.8%, but still inferior to the drop.

 

I guess the problem for GIB is that these percentages are pretty close. It'd be easy for a simulation to swing one way or the other.

 

edit: Note I've omitted a step here, which is to multiply the percentages by their outcomes to calculate expectation. For example, suppose the drop fails, if Q is with West you make 10 tricks but if Q is with East you make only 9. I should really get back to work now :/, will maybe fill this in later.

 

ahydra

[toastlots]

I really loved the OP's spelling of "uncharacteristically". :)

 

1eyedjack's analysis is good, but let's go deeper. Taking the finesse into West as opposed to playing for the drop loses to Q or Qx with West but gains when East has Qxx or Qxxx. What are the odds?

 

3-1 split = 49.7%, of which there are 8 combinations, one of which is singleton Q with West, so 6.2%

2-2 split = 40.7%, of which there are 6 combinations, three of which have Qx with West, so 20.3%

 

vs

3-1 split = 49.7%, of which there are 8 combinations, three of which have Qxx with East, so 18.6%

4-0 split = 9.6%, of which there are 2 combinations, one of which is Qxxx with East, so 4.8%

 

So to play the drop is slightly better: it gains 26.5% to 23.4% i.e. 0.031 more overtricks on average.

 

What about playing the K first, then finessing? Now you pick up the singleton Q with West (but can't pick up Qxxx in East), so the finesse improves to 24.8%, but still inferior to the drop.

 

I guess the problem for GIB is that these percentages are pretty close. It'd be easy for a simulation to swing one way or the other.

 

edit: Note I've omitted a step here, which is to multiply the percentages by their outcomes to calculate expectation. For example, suppose the drop fails, if Q is with West you make 10 tricks but if Q is with East you make only 9. I should really get back to work now :/, will maybe fill this in later.

 

ahydra

[toastlots]

Thank you both for those replies.

Wow i didnt realise one can bring up hands I have played like that after they have been played and the table finished, amazing.

Can I do that too?

Sorry but I am not expert enough to study hands like this, I just play any hand to get as many tricks as I can in the best way I can.

It just seemed daft not to make the assumption that the clubs were split 2-2, and even if 3-1 I know I can get back there to use all the remaining clubs to get the most tricks.

In fact I forgot to mention that later in that contract my gib partner had to throw a card and threw one of the clubs away and in my opinion wasting a certain trick by doing so.

The result where I believe we scored a minus seems to bear out my view on this particular hand.

[1eyedjack]

i didnt realise one can bring up hands I have played like that after they have been played and the table finished, amazing.

Can I do that too?

 

Yes you can. At least for a limited period for any given hand. For roughly 2 months the hands remain a matter of public record available to view at

http://online.bridge...hands/index.php

 

[EDIT] -the above link still works but is out of date - the correct URL should be

 

http://www.bridgebas...Hands/index.php

 

[/Edit]

 

 

Indeed if you access BBO by using the web-based "Flash" version of the interface you get rather more direct access.

 

After about 2 months the hands scroll off from public view although BBO keeps them backed up for a considerably longer period.

 

Sorry but I am not expert enough to study hands like this, I just play any hand to get as many tricks as I can in the best way I can.

It just seemed daft not to make the assumption that the clubs were split 2-2, and even if 3-1 I know I can get back there to use all the remaining clubs to get the most tricks.

In fact I forgot to mention that later in that contract my gib partner had to throw a card and threw one of the clubs away and in my opinion wasting a certain trick by doing so.

The result where I believe we scored a minus seems to bear out my view on this particular hand.

It is dangerous to draw from the result achieved against the room a conclusion that the hand was bid or played optimally or otherwise. If you play the hand "against" the field then you increase the chances of a swing, which could work either way. In the long term that variation may work in your favour and yet on a particular hand work against you. I suppose that in a strong field, and in the absence of doing your own analysis, it is not unreasonable to predict that the majority way of playing it was the "correct" one. But it comes with no guarantees.

 

Incidentally, at the time that he pitched a Club he did not concede any tricks. He had 10 tricks in the bag plus or minus zero at the time of that discard, whether it was a small club, heart or spade.