Author Topic: Fun with bots (and a Star)  (Read 1254 times)

jcreech

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Fun with bots (and a Star)
« on: September 08, 2021, 12:32:08 PM »
These are hands from a Star Challenge.  I thought they posed interesting decisions for both the South player (the star and I) and our bot partners.

Bd 1 None vul

You hold !S KT !H 32 !D J932 !C AKJ62 and it goes two passes to you.  12 HCPs and 2 spades, so only 14 Casino points; do you bid?  And if so what?

At one point, I would have opened 1 !D so that I would retain the easy rebid of 2 !C after 1 !S.  The lack of a heart stop can be of real concern, but I have come around, particularly when the choice of suits is Jxxx vs. AKJxx.  I now feel it is less of a lie to rebid the clubs or bid NT than it is to bid both minors. 

So at my table, it continued with a 1 !H overcall, 2 !H cue-bid showing club support, the heart game bid by East and I carried on to game.  Should the South hand bid or defend against 4 !H?  This is one of those gray areas where it is not entirely clear whose hand this is.  One rule of thumb says that the five-level belong to the opponents.  With partner showing a club fit, I felt we must have 9-11 clubs, and therefore most of my defense may easily disappear quickly.  To me, it felt like we have a better chance trying to make our game than trying to set theirs.  So I bid.  As it turns out, we have a 23 point sacrifice for their 17 point unbiddable slam.

The final result was a four IMP gain when the star decided to begin with 1 !D, and then the auction was identical except substituting diamonds for clubs.  The problem, though, was more luck than skill.  I only had to contend with a 4-0 trump break on a 5-4 fit; the star had a 5-0 break with a 4-4 fit.  The contract went down five tricks, compared to the two I went down.`

The full hand can be seen by clicking this link:  https://tinyurl.com/yk5cdkeu   


Bd 4  All vul

On this board, you could say that the star and I made the same bids, just in a different order.

The auction began with two passes to 1 !S, you hold !S T9 !H AK2 !D A72 !C KQJT8.  Your choices are essentially double and an overcall.  If you had a spade stop, there would be a third choice of 1NT, but with doubleton T9 it is better to remain among the mundane.  I chose to overcall.  To me, the suit was excellent, and with 3-3 in the reds, I preferred to back into those suits with a double later.  Little did I realize how the auction would progress.  West bid the spade game, and this was passed back to me.  Now I felt that 5 !C would be too unilateral, and that double would bring everything into view; my defense, that my suit was good, and I could reasonably support either red suit.

So let's now move to the other side of the table.  You hold !S 6 !H Q7654 !D Q3 !C 97532, partner has overcalled in one of your five-card suits, and suggests support for your other five-card suit, and the only defense you have are two queens.  Should you pass and defend, or bid one of your suits?  Personally, I would run to clubs where we have a 10-card or better fit; I just cannot imagine a hand where it would make more sense to pass than play when a double comes around to me.  What did the bot do?  It passed.  And the opponents wrapped up the double with an overtrick.

The star began with a double, West bid 4 !S, and this was passed back to the star.  What do you do?  Personally, I probably pass, but I can understand the decision to bid on.  The worst you can normally expect to lose is five tricks; if the opponents have a game, that is not much of a loss doubled, and they may not double having shown weakness.  Moreover, if partner has a cover card, even doubled it becomes a small potential win.  So bidding 5 !C is reasonable, even if it is not my cup of tea.  It might have been more interesting if the vulnerability had been white vs. red.  Then with many partners, I would be willing to bid 4NT saying I have at least two places to play opposite the takeout double.  That would easily get us to 5 !C, though it might draw a double, as it sounds weak.

I can't say that the overcall is definitively better than the double, but I think it will pay more dividends in the long run than the double.  It helps set the defense by providing a great lead director.  It helps keep your side from finding a 4-3 fit (whether it is right or wrong); certainly there are a lot of declarers that hate not having an eight-card fit.  And it may make it easier to find a fit-based sacrifice.


Nonetheless, it is also important to remember who is sitting across the table from you.  While a human being is unlikely to sit for the double, taking it for cooperative with takeout tolerances, the bot is much more likely to sit with a big fit and nothing to speak of in defensive values. 

A link to the full hand follows:  https://tinyurl.com/yf3rxetq


Bd 6  E-W vul

You hold !S A8 !H A2 !D K9875 !C AK74, and the auction goes one pass to you.  Too strong for 1NT and not strong enough for 2NT, you open 1 !D.  Partner raises to 2 !D, inverted, showing 10+ with diamond support.  West jump overcalls with 3 !S, and it is now your bid again.  Your room to explore has suddenly disappeared, what do you bid? 

Personally, I would love to pass if I was certain that partner would treat that as forcing.  It has the potential to obtain the most information about partner's hand while conserving the most space.  But, would the bot pass 3 !S?  The middle of an auction is not the time to experiment. 

With great controls and partner raising my five-card suit that could have been as short as three are pluses.  We are looking at a minimum of 29 HCPs a nine-card fit and  first-round control of all of the side suits.  The question is how much of partner's hand is wasted in the trump suit, and how much might be useful cover cards in the other suits.  The problem is, you really only have RKC available, and it is of limited usefulness. 

To buy time let's say you bid 4NT and partner responds 5 !D, showing 1 or four keycards.  Now what?  5 !H would ask about the queen and responses could tell you about the first-held king.  But what does that tell you?  The queen is actually a bad value if you have a 5-5 fit, because it is not helping in a side suit.  Ideally, you would like to see both major-suit kings, the diamond ace and either the club queen or a doubleton club.  Is there a way to ask all of that?  No!  So at some point you have to guess where to place the contract.

I decided to play partner for a minimum with substantial wastage in the diamond suit.  I made this decision partly on the fact that East bounced in red at the three-level, so I felt there should be some values outstanding to take that risk - that turned out to be a faulty assumption.  Partly on the fact that partner should have 4-6 diamonds, and that increased the chances that a substantial portion of the hand was in the diamond suit - which turned out to be a good assumption.  And partly on the fact that I needed five cover cards for a grand slam - that seemed a bit much, but if I make a slam move, and partner has that sort of hand, there should be no way we stop short of the grand -  this may not have been a fully thought-out assumption, that is, I may need to ask about the queen to get partner to feel certain that we have all of the keycards.

Anyway, I chose to bid six, while the star chose to bid seven.  I happened to be right, and the star wrong, but it could have easily be reversed.  Swap the red queens (keeping the jacks), I would have liked my chances until East did not really have it's bid.

The full hand can be seen by clicking on this link:  https://tinyurl.com/yf9p4n9t
« Last Edit: September 08, 2021, 07:41:52 PM by jcreech »
A stairway to nowhere is better than no stairway at all.  -Kehlog Albran

kenberg

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Re: Fun with bots (and a Star)
« Reply #1 on: September 08, 2021, 01:56:09 PM »
I will look at all of them but for now I will comment on the first of them.  I decided on whether to pass it out or open before I read the rest or looked at the hands, and I decided to pass it out.

Larry Cohen has his own ideas about when to open in 4th seat, see https://www.larryco.com/bridge-articles/rule-of-15-and-crifs, and I have mine.  Mine dates back to Goren. I look at my hand, think of partner's likely response, and see if I will be happy about my next call. If I am to open this, I certainly open it 1C, not 1D. I will not be happy if partner responds 1H, but I will be even less happy with a 1S response. 1C-1S-1NT seems suicidal. Also, it could go 1C-(1H0-X(negative). People do make negative doubles holding four hearts but only three diamonds. Yuk.
As to opening 1D I know some would, and apparently your star opponent is one who does.  So if it goes 1D-1S-2C (umcontested0 partner is supposed to do what? If he is 3-3 in the minors he has a problem. In fact he also has a problem if he holds three diamonds and two clubs. Playing in a 4-3 miht not be awful, but when holding J932 it usually is. And for that matter he might be a bit uncertain when he holds Qx in diamonds and xxx in clubs. As it is, he wants to pass and let you play in your 5-3 fit. But if your clubs and diamonds are reversed. say D:  AKJ62; C: xxx  I think you really want to hear 2D from him on his D: Qx; C: xxx.

So 1D, then 2C creates problems, serious problems.

Of course the downside of opening 1C and then rebidding 2C is you might end in a 5-1 fit. Could be, but that need not be a disaster. You are short in the majors and, in this hypothetical 5-1 fit,  you might well play 2C by ruffing majors small in hand, cashing high trumps, and let them have the rest.

And finally, if W ends up as declarer, you would no doubt prefer a club lead from partner rather than a D lead. Maybe not this time with the void on your right, but usually.


So: If I open, I open 1C. But I don't care much for the "What happens next?" question, so I pass.
Ken

kenberg

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Re: Fun with bots (and a Star)
« Reply #2 on: September 08, 2021, 07:35:20 PM »
On bd 4 (btw you did not include the club T in your description), the hand, for me, is a 2C call just as it was for you. I think it's close, or sort of close, but I have a good cub suit, and if the auction comes back to me at the 2S or 3S level then a double should make everything very clear. Unfortunately, it comes back as 4S and, again, unfortunately, you are playing with a bot. On many hands I think the bots do pretty well but this sort of thing is a weakness for them. They have their algorithm, and some plausibly thinking is what is needed. N can easily see that however many tricks S hoped to get in clubs, they are not likely to be there.

After that observation, I think N should reason that anytime we can beat 4H we can also make 5C.  As it turns out, you can't beat 4S and you can't make 5 of anything. Playing with a human, the real danger is apt to be that after N pulls to 5C and the opponents go on to 5S, S doubles again. My general rule, as N, would be not to pull this. I already told pard I am not enthusiastic about defending a spade contract, so if he doubles 5S he is on his own.

As to the Manfield Maxim, "The Five Level Belongs to the Opponents", like most maxims it has merit and like most maxims it is not E=Mc^2, the latter being always right as far as I know. 5S is unbeatable, 5CX is going down 1. Sometimes "The Five Level Belongs to Me".
Ken

kenberg

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Re: Fun with bots (and a Star)
« Reply #3 on: September 08, 2021, 08:05:47 PM »
On bd 6 I am pretty sure that I would have bid 4C over E's 3S.  After that it might go, with no further interference, 4D-4H-?
We might be going toward letting N make the final decision. If he is thinking of 7D he might think: Pard needs the spade A and the diamond K. Is it really reasonable to think that he also has the heart AK and the club AK? And if he has that, maybe he would have taken control?

Anyway, I think I would have bid 4C over 3S but I am not at all sure what happens after that.  I might try the bots on these hands, all seats held by bots, and see what they do.
Ken